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  • Build 2012, some thoughts..

    - by Dennis Vroegop
    I think you probably read my rant about the logistics at Build 2012, as posted here, so I am not going into that anymore. Instead, let’s look at the content. (BTW If you did read that post and want some more info then read Nia Angelina’s post about Build. I have nothing to add to that.) As usual, there were good speakers and some speakers who could benefit from some speaker training. I find it hard to understand why Microsoft allows certain people on stage, people who speak English with such strong accents it’s hard for people, especially from abroad, to understand. Some basic training might be useful for some of them. However, it is nice to see that most speakers are project managers, program managers or even devs on the teams that build the stuff they talk about: there was a lot of knowledge on stage! And that means when you ask questions you get very relevant information. I realize I am not the average audience member here, I am regular speaker myself so I tend to look for other things when I am in a room than most audience members so my opinion might differ from others. All in all the knowledge of the speakers was above average but the presentation skills were most of the times below what I would describe as adequate. But let us look at the contents. Since the official name of the conference is Build Windows 2012 it is not surprising most of the talks were focused on building Windows 8 apps. Next to that, there was a lot of focus on Azure and of course Windows Phone 8 that launched the day before Build started. Most sessions dealt with C# and JavaScript although I did see a tendency to use C++ more. Touch. Well, that was the focus on a lot of sessions, that goes without saying. Microsoft is really betting on Touch these days and being a Touch oriented developer I can only applaud this. The term NUI is getting a bit outdated but the principles behind it certainly aren’t. The sessions did cover quite a lot on how to make your applications easy to use and easy to understand. However, not all is touch nowadays; still the majority of people use keyboard and mouse to interact with their machines (or, as I do, use keyboard, mouse AND touch at the same time). Microsoft understands this and has spend some serious thoughts on this as well. It was all about making your apps run everywhere on all sorts of devices and in all sorts of scenarios. I have seen a couple of sessions focusing on the portable class library and on sharing code between Windows 8 and Windows Phone 8. You get the feeling Microsoft is enabling us devs to write software that will be ubiquitous. They want your stuff to be all over the place and they do anything they can to help. To achieve that goal they provide us with brilliant SDK’s, great tooling, a very, very good backend in the form of Windows Azure (I was particularly impressed by the Mobility part of Azure) and some fantastic hardware. And speaking of hardware: the partners such as Acer, Lenovo and Dell are making hardware that puts Apple to a shame nowadays. To illustrate: in Bellevue (very close to Redmond where Microsoft HQ is) they have the Microsoft Store located very close to the Apple Store, so it’s easy to compare devices. And I have to say: the Microsoft offerings are much, much more appealing that what the Cupertino guys have to offer. That was very visible by the number of people visiting the stores: even on the day that Apple launched the iPad Mini there were more people in the Microsoft store than in the Apple store. So, the future looks like it’s going to be fun. Great hardware (did I mention the Nokia Lumia 920? No? It’s brilliant), great software (Windows 8 is in a league of its own), the best dev tools (Visual Studio 2012 is still the champion here) and a fantastic backend (Azure.. need I say more?). It’s up to us devs to fill up the stores with applications that matches this. To summarize: it is great to be a Windows developer. PS. Did I mention Surface RT? Man….. People were drooling all over it wherever I went. It is fantastic :-) Technorati Tags: Build,Windows 8,Windows Phone,Lumia,Surface,Microsoft

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  • Optimistic non-locking copy of InnoDB .frm files

    - by jothir
    MySQL Enterprise Backup(MEB) does hot backup of innodb data and log files. Till MEB 3.6.1, the user backs up the only innodb tables in a 3 step process: STEP 1. Take backup using --only-innodb option STEP 2. Temporarily make the table read only by executing “FLUSH TABLES WITH READ LOCK” MEB 3.7.0 has an enhancement to innodb file copying. The .frm files gets copied along with the hot backup done for innodb files. I would like to make the blog a little interactive by explaining the feature as answers: 1. What are these .frm files? The files containing the metadata, such as the table definition, of a MySQL table. For backups, the full set of .frm files are always required along with the backup data, to be able to restore tables that are altered or dropped after the backup. 2. Can the .frm files not be copied by MEB itself? --only-innodb-with-frm is the new option introduced in MEB 3.7.1 to do a copy of .frm files without locking the tables during backup operation itself. This is to reduce the pain of manually copying the .frm files. The option is intended for backups where you can ensure that no ALTER TABLE, CREATE TABLE, DROP TABLE, or other DDL statements modify the .frm files for InnoDB tables during the backup operation. 3. How is data consistency ensured? MEB does validation of the .frm files after copying by comparing with the server directory to see if the timestamps of any of the .frm files is greater than the saved system time (check .frm time).  This change in timestamp of the .frm files will show if a table is altered during the process of backup. The total number of frm files in the server directory is also verified against the copied contents. If the number of .frm files is less compared to server directory, it shows that table/tables have been dropped during the process of backup. If the number of .frm files is more compared to server directory, it shows that new table/tables have been created during backup operation. 4. How does MEB handle data inconsistency? MEB copies the .frm files through several iterations,  does the validation and throws a WARNING if there is any inconsistency found in .frm files at the end of backup operation. This means the user is warned of some DDL operations that had occurred during backup operation, and has to manually copy the .frm files or do a backup again. 5. What is the option and explain its usage? The option introduced is --only-innodb-with-frm which does optimistic copy of .frm files without locking. This can be used when the user wants to backup only innodb tables along with .frm files. The option can take one of the 2 values: all | related. --only-innodb-with-frm=all does copy of all .frm files of all innodb tables. --only-innodb-with-frm=related works in conjunction with --include option.This is to allow partial backup of .frm files corresponding to the tables specified in --include. Let me show the usage with example output: ./mysqlbackup -uroot --backup-dir=/logs/backupWithFrmAll --only-innodb-with-frm=all backup MySQL Enterprise Backup version 3.7.1 [2012/06/05] Copyright (c) 2003, 2012, Oracle and/or its affiliates. All Rights Reserved. INFO: Starting with following command line ... ./mysqlbackup -uroot --backup-dir=/logs/backupWithFrmAll        --only-innodb-with-frm=all backup INFO: Got some server configuration information from running server. IMPORTANT: Please check that mysqlbackup run completes successfully.            At the end of a successful 'backup' run mysqlbackup            prints "mysqlbackup completed OK!". --------------------------------------------------------------------                       Server Repository Options: --------------------------------------------------------------------  datadir                          =  /mysql/trydb/  innodb_data_home_dir             =    innodb_data_file_path            =  ibdata1:10M:autoextend  innodb_log_group_home_dir        =  /mysql/trydb/  innodb_log_files_in_group        =  2  innodb_log_file_size             =  5242880 --------------------------------------------------------------------                       Backup Config Options: --------------------------------------------------------------------  datadir                          =  /logs/backupWithFrmAll/datadir  innodb_data_home_dir             =  /logs/backupWithFrmAll/datadir  innodb_data_file_path            =  ibdata1:10M:autoextend  innodb_log_group_home_dir        =  /logs/backupWithFrmAll/datadir  innodb_log_files_in_group        =  2  innodb_log_file_size             =  5242880 mysqlbackup: INFO: Unique generated backup id for this is 13451979804504860 mysqlbackup: INFO: Uses posix_fadvise() for performance optimization. mysqlbackup: INFO: System tablespace file format is Antelope. mysqlbackup: INFO: Found checkpoint at lsn 1656792. mysqlbackup: INFO: Starting log scan from lsn 1656320. 120817 15:36:22 mysqlbackup: INFO: Copying log... 120817 15:36:22 mysqlbackup: INFO: Log copied, lsn 1656792.          We wait 1 second before starting copying the data files... 120817 15:36:23 mysqlbackup: INFO: Copying /mysql/trydb/ibdata1 (Antelope file format). 120817 15:36:23 mysqlbackup: INFO: Copying /mysql/trydb/innodb1/table2.ibd (Antelope file format). 120817 15:36:23 mysqlbackup: INFO: Copying /mysql/trydb/innodb1/table3.ibd (Antelope file format). 120817 15:36:23 mysqlbackup: INFO: Copying /mysql/trydb/innodb1/table1.ibd (Antelope file format). mysqlbackup: INFO: Opening backup source directory '/mysql/trydb/' 120817 15:36:23 mysqlbackup: INFO: Starting to backup .frm files in the subdirectories of /mysql/trydb/ mysqlbackup: INFO: Copying innodb data and logs during final stage ... mysqlbackup: INFO: A copied database page was modified at 1656792.          (This is the highest lsn found on page)          Scanned log up to lsn 1656792.          Was able to parse the log up to lsn 1656792.          Maximum page number for a log record 0 mysqlbackup: INFO: Copying non-innodb files took 2.000 seconds 120817 15:36:25 mysqlbackup: INFO: Full backup completed! mysqlbackup: INFO: Backup created in directory '/logs/backupWithFrmAll' -------------------------------------------------------------   Parameters Summary          -------------------------------------------------------------   Start LSN                  : 1656320   End LSN                    : 1656792 ------------------------------------------------------------- mysqlbackup completed OK! bash$ ls /logs/backupWithFrmAll/datadir/innodb1/ table1.frm  table1.ibd  table2.frm  table2.ibd  table3.frm  table3.ibd Here the backup directory contains all the .frm files of all the innodb tables. ./mysqlbackup -uroot --backup-dir=/logs/backupWithFrm --include="innodb1.table3.*" --only-innodb-with-frm=related backup MySQL Enterprise Backup version 3.7.1 [2012/06/05] Copyright (c) 2003, 2012, Oracle and/or its affiliates. All Rights Reserved. INFO: Starting with following command line ... ./mysqlbackup -uroot --backup-dir=/logs/backup371frm        --include=innodb1.table3.* --only-innodb-with-frm=related backup INFO: Got some server configuration information from running server. IMPORTANT: Please check that mysqlbackup run completes successfully.            At the end of a successful 'backup' run mysqlbackup            prints "mysqlbackup completed OK!". --------------------------------------------------------------------                       Server Repository Options: --------------------------------------------------------------------  datadir                          = /mysql/trydb/  innodb_data_home_dir             =    innodb_data_file_path            =  ibdata1:10M:autoextend  innodb_log_group_home_dir        =  /mysql/trydb  innodb_log_files_in_group        =  2  innodb_log_file_size             =  5242880 --------------------------------------------------------------------                       Backup Config Options: --------------------------------------------------------------------  datadir                          =  /logs/backupWithFrm/datadir  innodb_data_home_dir             =  /logs/backupWithFrm/datadir  innodb_data_file_path            =  ibdata1:10M:autoextend  innodb_log_group_home_dir        =  /logs/backupWithFrm/datadir  innodb_log_files_in_group        =  2  innodb_log_file_size             =  5242880 mysqlbackup: INFO: Unique generated backup id for this is 13451973458118162 mysqlbackup: INFO: Uses posix_fadvise() for performance optimization. mysqlbackup: INFO: The --include option specified: innodb1.table3.* mysqlbackup: INFO: System tablespace file format is Antelope. mysqlbackup: INFO: Found checkpoint at lsn 1656792. mysqlbackup: INFO: Starting log scan from lsn 1656320. 120817 15:25:47 mysqlbackup: INFO: Copying log... 120817 15:25:47 mysqlbackup: INFO: Log copied, lsn 1656792.          We wait 1 second before starting copying the data files... 120817 15:25:48 mysqlbackup: INFO: Copying /mysql/trydbibdata1 (Antelope file format). 120817 15:25:49 mysqlbackup: INFO: Copying /mysql/trydbinnodb1/table3.ibd (Antelope file format). mysqlbackup: INFO: Opening backup source directory '/mysql/trydb' 120817 15:25:49 mysqlbackup: INFO: Starting to backup .frm files in the subdirectories of /mysql/trydb mysqlbackup: INFO: Copying innodb data and logs during final stage ... mysqlbackup: INFO: A copied database page was modified at 1656792.          (This is the highest lsn found on page)          Scanned log up to lsn 1656792.          Was able to parse the log up to lsn 1656792.          Maximum page number for a log record 0 mysqlbackup: INFO: Copying non-innodb files took 2.000 seconds 120817 15:25:51 mysqlbackup: INFO: Full backup completed! mysqlbackup: INFO: Backup created in directory '/logs/backupWithFrm' -------------------------------------------------------------   Parameters Summary          -------------------------------------------------------------   Start LSN                  : 1656320   End LSN                    : 1656792 ------------------------------------------------------------- mysqlbackup completed OK! bash$ ls /logs/backupWithFrm/datadir/innodb1/ table3.frm table3.ibd Thus the backup directory contains only the .frm file matching the innodb table name specified in --include option. In a nutshell, we present our great new option --only-innodb-with-frm which is a true hot InnoDB-only backup with .frm files, but with an additional check, if any DDL happened during the backup. If a DDL has happened, the DBA can decide if to repeat the backup, or to live with the potential inconsistency. This is the ideal solution for users that have all their "real" data in InnoDB and seldom change their schemas. You may also like: http://dev.mysql.com/doc/mysql-enterprise-backup/3.7/en/backup-partial-options.html   STEP 3. Manually copy the .frm files of innodb tables to the destination directory where backup is stored.

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  • CodePlex Daily Summary for Thursday, May 15, 2014

    CodePlex Daily Summary for Thursday, May 15, 2014Popular ReleasesVisualizers: Visualizer: This dll is the core of the project just copy and paste it in the following folder %Microsoft Visual Studio%\Common7\Packages\Debugger\Visualizers where %Microsoft Visual Studio% is the Visual studio installation folderQuickMon: Version 3.10: Adding the ability to see 'history' of Collector states (including details of errors or warnings at that time). The history size is configurable (default is switched off) and the Windows Service completely ignores keeping history (no UI or user to access it anyway). The Collector stats window now displays this history plus multiple collector stats windows can be opened at the same time. Additionally fixed a bug in the event log collector that reported an 'Error' state when an 'out of bounds' ...xFunc: xFunc 2.15.4: Fixed bug in Processor.csTFS Planning and Disaster Recovery Avoidance Guide: v1.4.BETA - TFS, DR and Azure IaaS Planning Guides: Welcome to the TFS Planning and DR Avoidance Guidance What is new? A new crisper, more compact style, which is easier to consume on multiple devices without sacrificing any content. Also included are the new TFS on Azure IaaS guide and supplementary guides. Note Capacity planning workbook and posters are included in the Everything Zip package. Quality-Bar Detail Documentation has been reviewed by Visual Studio ALM Rangers Documentation has been through an independent technical review ...WinAudit: WinAudit Freeware v3.0: WinAudit.exe v3.0 MD5: 88750CCF49FF7418199B2645755830FA Known Issues: 1. Report creation can be very slow when right-to-left (Hebrew) characters are present. 2. Emsisoft Anti-Malware may stop and/or quarantine WinAudit. This happens when WinAudit attempts to obtain a list if running programmes. You will need to set an exception rule in Emsisoft to allow WinAudit to run.MVCwCMS - ASP.NET MVC CMS: MVCwCMS 2.2.2: Updated CKFinder config. For the installation instructions visit the documentation page: https://mvcwcms.codeplex.com/documentationTerraMap (Terraria World Map Viewer): TerraMap 1.0.4: Added support for the new Terraria v1.2.4 update. New items, walls, and tiles Fixed Issue 35206: Hightlight/Find doesn't work for Demon Altars Fixed finding Demon Hearts/Shadow Orbs Added ability to find Enchanted Swords (in the stone) and Water Bolt books Fixed installer not uninstalling older versions The setup file will make sure .NET 4 is installed, install TerraMap, create desktop and start menu shortcuts, add a .wld file association, and launch TerraMap. If you prefer the zip ...WPF Localization Extension: v2.2.1: Issue #9277 Issue #9292 Issue #9311 Issue #9312 Issue #9313 Issue #9314CtrlAltStudio Viewer: CtrlAltStudio Viewer 1.2.1.41167 Release: This release of the CtrlAltStudio Viewer includes the following significant features: Oculus Rift support. Stereoscopic 3D display support. Variable walking / flying speed. Xbox 360 Controller support. Kinect for Windows support. Based on Firestorm viewer 4.6.5 codebase. For more details, see the release notes linked to below. Release notes: http://ctrlaltstudio.com/viewer/release-notes/1-2-1-41167-release Support info: http://ctrlaltstudio.com/viewer/support Privacy policy: http:/...ExtJS based ASP.NET Controls: FineUI v4.0.6: FineUI(???) ?? ExtJS ??? ASP.NET ??? FineUI??? ?? No JavaScript,No CSS,No UpdatePanel,No ViewState,No WebServices ??????? ?????? IE 8.0+、Chrome、Firefox、Opera、Safari ???? Apache License v2.0 ?:ExtJS ?? GPL v3 ?????(http://www.sencha.com/license) ???? ??:http://fineui.com/ ??:http://fineui.com/bbs/ ??:http://fineui.com/demo/ ??:http://fineui.com/doc/ ??:http://fineui.codeplex.com/ FineUI ???? ExtJS ????????,???? ExtJS ?,?????: 1. ????? FineUI ? ExtJS ? http://fineui.com/bbs/forum.ph...Office App Model Samples: Office App Model Samples v2.0: Office App Model Samples v2.0Readable Passphrase Generator: KeePass Plugin 0.13.0: Version 0.13.0 Added "mutators" which add uppercase and numbers to passphrases (to help complying with upper, lower, number complexity rules). Additional API methods which help consuming the generator from 3rd party c# projects. 13,160 words in the default dictionary (~600 more than previous release).CS-Script for Notepad++ (C# intellisense and code execution): Release v1.0.25.0: Release v1.0.25.0 MemberInfo/MethodInfo popup is now positioned properly to fit the screen In MethodInfo popup method signatures are word-wrapped Implemented Debug text value visualizer Pining sub-values from Watch PanelWrapper for the PAYMILL API: Paymill API Wrapper: Add Description in PreauthorizationHow to develop an autodialer / predictive dialer in C#: VoIP AutoDialer in C Sharp: This is the downloadable source code for this example project that is intended to help you in developing your own VoIP autodialer application in C#.R.NET: R.NET 1.5.12: R.NET 1.5.12 is a beta release towards R.NET 1.6. You are encouraged to use 1.5.12 now and give feedback. See the documentation for setup and usage instructions. Main changes for R.NET 1.5.12: The C stack limit was not disabled on Windows. For reasons possibly peculiar to R, this means that non-concurrent access to R from multiple threads was not stable. This is now fixed, with the fix validated with a unit test. Thanks to Odugen, skyguy94, and previously others (evolvedmicrobe, tomasp) fo...SEToolbox: SEToolbox 01.029.006 Release 1: Fix to allow keyboard search on load dialog. (type the first few letters of your save) Fixed check for new release. Changed the way ship details are loaded to alleviate load time for worlds with very large ships (100,000+ blocks). Fixed Image importer, was incorrectly listing 'Asteroid' as import option. Minor changes to menus (text and appearance) for clarity and OS consistency. Added in reading of world palette for color dialog editor. WIP on subsystem editor. Can now multiselec...Thaumcraft4 Research: Alpha 2 release, lots of awesome improvements: Performance inprovements asynchronous running of the search Search result-cap ( usefull for long routes, it wont try to find 3000 results ) statistics addedTiny Wifi Host: Tiny Wifi Host 3.0.0.0: Tiny Wifi Hotspot Creator (Portable) v3 size: 50KB-140KB New Features: Friendly name for connected devices instead of Mac-Address (Double click selected device to enter friendly name) Saves device names to devices.xml Better error reporting+solutions Warning sound when number of connected devices exceed a certain number. (useful when only certain number of devices must be connected at a time) Many Bug Fixes. NoAudio files does not include connect, disconnect and warning audio to dec...Media Companion: Media Companion MC3.597b: Thank you for being patient, againThere are a number of fixes in place with this release. and some new features added. Most are self explanatory, so check out the options in Preferences. Couple of new Features:* Movie - Allow save Title and Sort Title in Title Case format. * Movie - Allow save fanart.jpg if movie in folder. * TV - display episode source. Get episode source from episode filename. Fixed:* Movie - Added Fill Tags from plot keywords to Batch Rescraper. * Movie - Fixed TMDB s...New ProjectsBLADE View Engine - An independent RAZOR alternative: An alternative parser and view engine to Asp.net Razor that does not depend on Asp.net or .NET 4.5BPL++: A basic object orientated programming language built upon a virtual machine using C#Caedisi - A Cellular Automata Editor and Simulator for Network Decontamination: A research tool that explores the use of cellular automata in order to decontaminate a network attacked or infected by a virus. Cosmos Software Distrobution 1.0: No content until project released!ETCQuality: ETC QUALITY STAT SYSTEM. ????????????,??????????????。F.A.Q.: F.A.Q. project about Frequently asked questions. Help Viewer Redirector: Enables use of Help Viewer 2.0 or 2.1 with SQL Server instead of Help Viewer 1.0Jet.Payment.Cielo: Projeto contém integração com o serviço e-commerce Cielo, desenvolvido em C#. Criamos esse Helper para nossa própria necessidade. Nos ajude a melhorá-lo.Learning with Pati: Learning Javascript with PatiLeRenard: LeRenard is a collection of solutions (from core helper, extension methods) to libraries, all written in C# to help build applications.MCMP.NET: MCMP.NET allows ASP.NET applications to be added as contexts using mod_cluster.PowerShell Deployment Automation Framework: This project contains resources related to my blog at www.powershellcoach.compravda-f: ??????????? ? ?????? ??? ?????????? ??????sdir: Colorful, sorted and optionally rich directory enumeration for Windows.SienSchoofsProject: school project for .NET ExpertSorting collection of any type by several fields: Sorting collection of any type by several fields with using Reflection and Expression TreesTPS BarCode Scanner: This is going to be a collaboration platform for TPS team. We want to develop a simple low cost bar code generator and scanner system. This project is currentlVerifyDomainOutlookAddIn: ??????????????????????????????。Ynote Packages: Ynote Packages are a collection of tools which a play a crucial role in extending Ynote Classic and understanding it's true potential.??????-??????【??】??????????: ??????????????????,???、???!???????,????????????????,????????????,???! ?????-?????【??】?????????: ????????????、?????、?????、?????、?????、????,???????????,?????,??????! ?????-?????【??】?????????: ???????????????,?????????????? ??。??????????、????、????、?????????? ???????。 ??????-??????【??】??????????: ????????????????????,?????,???????,???????????,??????! ??????-??????【??】??????????: ??????????????、??????、????、?????、?????!????,????????????????!????。 ?????-?????【??】?????????: ???????????????????,?????????????????????,?????,????,???????. ?????-?????【??】?????????: ???????????????????、????????、????????、????????、???????,????????????。 ??????-??????【??】??????????: ????????????????、?????、?????、????、?????,??????????。????????????????! ??????-??????【??】??????????: ???????????????????????:????、????、??????????????,????????。????????! ????-????【??】????????: ?????????????????????,????????????,?????、??、????,?????,??????! ?????-?????【??】?????????: ???????????????????,??????????,????????、????,??????????,??????????。 ?????-?????【??】?????????: ???????,??????:?????,?????,??????,??????????,????????。????????! ????: ????????,????????????????????????,?????????,????????????????。????????????????????,??????????????,?????????????。 ????????????,?:   ??????   ??????   ????????   ??????-??????【??】??????????: ??????????????????????,???????????????,????????????????????! ??????-??????【??】??????????: ??????????????????、????,??100%????,??????,????????????,???????????! ????-????【??】????????: ???????????、??????????????????,????????,?????,??????,????,????,????! ?????-?????【??】?????????: ????????????????,??????????、??????,??????????、????、????、???????。 ?????--?????【??】?????????: ?????????????????????,???????????????,???????,?????,?????,????? !!!

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  • "Can't create table" when having to many partitions

    - by Chris
    I am currently having a problem I dont understand. Wherever I look it says mySQL (5.5) / InnoDB doesnt have a table limit. I wanted to test the InnoDB compression and was about to create an empty copy of an existing table and ran into the following problem. this one works: CREATE TABLE `hsc` ( LOTS OF STUFF ) ENGINE=InnoDB CHARSET=utf8 PARTITION BY RANGE (pid) SUBPARTITION BY HASH (cons) SUBPARTITIONS 2 (PARTITION hsc_p0 VALUES LESS THAN (10000) , PARTITION hsc_p1 VALUES LESS THAN (20000) , PARTITION hsc_p2 VALUES LESS THAN (30000) , PARTITION hsc_p3 VALUES LESS THAN (40000) , PARTITION hsc_p4 VALUES LESS THAN (50000) , PARTITION hsc_p40 VALUES LESS THAN (4000000) ); this one doesn't: CREATE TABLE `hsc` ( LOTS OF STUFF ) ENGINE=InnoDB CHARSET=utf8 PARTITION BY RANGE (pid) SUBPARTITION BY HASH (cons) SUBPARTITIONS 2 (PARTITION hsc_p0 VALUES LESS THAN (10000) , PARTITION hsc_p1 VALUES LESS THAN (20000) , PARTITION hsc_p2 VALUES LESS THAN (30000) , PARTITION hsc_p3 VALUES LESS THAN (40000) , PARTITION hsc_p4 VALUES LESS THAN (50000) , PARTITION hsc_p5 VALUES LESS THAN (75000) , PARTITION hsc_p6 VALUES LESS THAN (100000) , PARTITION hsc_p7 VALUES LESS THAN (125000) , PARTITION hsc_p8 VALUES LESS THAN (150000) , PARTITION hsc_p9 VALUES LESS THAN (175000) , PARTITION hsc_p40 VALUES LESS THAN (4000000) ); ERROR 1005 (HY000): Can't create table 'hsc' (errno: 1) Its reproducable by removing the number of partitions and adding them again. it does not have to do anything with the name of the table as i tried various names. there is also enough empty space on the HDD. /dev/simfs 230G 26G 192G 12% /var/lib/mysql.mnt There should be no limit on the partitions http://dev.mysql.com/doc/refman/5.5/en/partitioning-limitations.html Maximum number of partitions. The maximum possible number of partitions for a given table (that does not use the NDB storage engine) is 1024. This number includes subpartitions. i have increased both open_files show variables where variable_name LIKE '%open_files%'; +-------------------+-------+ | Variable_name | Value | +-------------------+-------+ | innodb_open_files | 512 | | open_files_limit | 1536 | +-------------------+-------+ No change. Any clues where should I start looking? UPDATE: the whole thing is running in an openvz environment. i saw in users_beancounters that the numflock was a problem, so i increased it. but the problem still persists. maybe this helps: ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 515011 max locked memory (kbytes, -l) 64 max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 10240 cpu time (seconds, -t) unlimited max user processes (-u) 515011 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited cat /proc/user_beancounters Version: 2.5 uid resource held maxheld barrier limit failcnt 200: kmemsize 9309653 13357056 14372700 14790164 0 lockedpages 0 1008 2048 2048 0 privvmpages 675424 686528 1048576 1572864 0 shmpages 33 673 21504 21504 0 dummy 0 0 9223372036854775807 9223372036854775807 0 numproc 49 90 240 240 0 physpages 243761 246945 0 9223372036854775807 0 vmguarpages 0 0 1048576 1048576 0 oomguarpages 81672 83305 1048576 1048576 0 numtcpsock 6 8 360 360 0 numflock 175 188 512 512 8 numpty 1 9 16 16 0 numsiginfo 0 48 256 256 0 tcpsndbuf 104640 263912 1720320 2703360 0 tcprcvbuf 98304 131072 1720320 2703360 0 othersockbuf 32368 89304 1126080 2097152 0 dgramrcvbuf 0 2312 262144 262144 0 numothersock 19 28 360 360 0 dcachesize 2285052 3624426 3409920 3624960 0 numfile 616 870 9312 9312 0 dummy 0 0 9223372036854775807 9223372036854775807 0 dummy 0 0 9223372036854775807 9223372036854775807 0 dummy 0 0 9223372036854775807 9223372036854775807 0 numiptent 24 24 128 128 0

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  • Visual Tree Enumeration

    - by codingbloke
    I feel compelled to post this blog because I find I’m repeatedly posting this same code in silverlight and windows-phone-7 answers in Stackoverflow. One common task that we feel we need to do is burrow into the visual tree in a Silverlight or Windows Phone 7 application (actually more recently I found myself doing this in WPF as well).  This allows access to details that aren’t exposed directly by some controls.  A good example of this sort of requirement is found in the “Restoring exact scroll position of a listbox in Windows Phone 7”  question on stackoverflow.  This required that the scroll position of the scroll viewer internal to a listbox be accessed. A caveat One caveat here is that we should seriously challenge the need for this burrowing since it may indicate that there is a design problem.  Burrowing into the visual tree or indeed burrowing out to containing ancestors could represent significant coupling between module boundaries and that generally isn’t a good idea. Why isn’t this idea just not cast aside as a no-no?  Well the whole concept of a “Templated Control”, which are in extensive use in these applications, opens the coupling between the content of the visual tree and the internal code of a control.   For example, I can completely change the appearance and positioning of elements that make up a ComboBox.  The ComboBox control relies on specific template parts having set names of a specified type being present in my template.  Rightly or wrongly this does kind of give license to writing code that has similar coupling. Hasn’t this been done already? Yes it has.  There are number of blogs already out there with similar solutions.  In fact if you are using Silverlight toolkit the VisualTreeExtensions class already provides this feature.  However I prefer my specific code because of the simplicity principle I hold to.  Only write the minimum code necessary to give all the features needed.  In this case I add just two extension methods Ancestors and Descendents, note I don’t bother with “Get” or “Visual” prefixes.  Also I haven’t added Parent or Children methods nor additional “AndSelf” methods because all but Children is achievable with the addition of some other Linq methods.  I decided to give Descendents an additional overload for depth hence a depth of 1 is equivalent to Children but this overload is a little more flexible than simply Children. So here is the code:- VisualTreeEnumeration public static class VisualTreeEnumeration {     public static IEnumerable<DependencyObject> Descendents(this DependencyObject root, int depth)     {         int count = VisualTreeHelper.GetChildrenCount(root);         for (int i = 0; i < count; i++)         {             var child = VisualTreeHelper.GetChild(root, i);             yield return child;             if (depth > 0)             {                 foreach (var descendent in Descendents(child, --depth))                     yield return descendent;             }         }     }     public static IEnumerable<DependencyObject> Descendents(this DependencyObject root)     {         return Descendents(root, Int32.MaxValue);     }     public static IEnumerable<DependencyObject> Ancestors(this DependencyObject root)     {         DependencyObject current = VisualTreeHelper.GetParent(root);         while (current != null)         {             yield return current;             current = VisualTreeHelper.GetParent(current);         }     } }   Usage examples The following are some examples of how to combine the above extension methods with Linq to generate the other axis scenarios that tree traversal code might require. Missing Axis Scenarios var parent = control.Ancestors().Take(1).FirstOrDefault(); var children = control.Descendents(1); var previousSiblings = control.Ancestors().Take(1)     .SelectMany(p => p.Descendents(1).TakeWhile(c => c != control)); var followingSiblings = control.Ancestors().Take(1)     .SelectMany(p => p.Descendents(1).SkipWhile(c => c != control).Skip(1)); var ancestorsAndSelf = Enumerable.Repeat((DependencyObject)control, 1)     .Concat(control.Ancestors()); var descendentsAndSelf = Enumerable.Repeat((DependencyObject)control, 1)     .Concat(control.Descendents()); You might ask why I don’t just include these in the VisualTreeEnumerator.  I don’t on the principle of only including code that is actually needed.  If you find that one or more of the above  is needed in your code then go ahead and create additional methods.  One of the downsides to Extension methods is that they can make finding the method you actually want in intellisense harder. Here are some real world usage scenarios for these methods:- Real World Scenarios //Gets the internal scrollviewer of a ListBox ScrollViewer sv = someListBox.Descendents().OfType<ScrollViewer>().FirstOrDefault(); // Get all text boxes in current UserControl:- var textBoxes = this.Descendents().OfType<TextBox>(); // All UIElement direct children of the layout root grid:- var topLevelElements = LayoutRoot.Descendents(0).OfType<UIElement>(); // Find the containing `ListBoxItem` for a UIElement:- var container = elem.Ancestors().OfType<ListBoxItem>().FirstOrDefault(); // Seek a button with the name "PinkElephants" even if outside of the current Namescope:- var pinkElephantsButton = this.Descendents()     .OfType<Button>()     .FirstOrDefault(b => b.Name == "PinkElephants"); //Clear all checkboxes with the name "Selector" in a Treeview foreach (CheckBox checkBox in elem.Descendents()     .OfType<CheckBox>().Where(c => c.Name == "Selector")) {     checkBox.IsChecked = false; }   The last couple of examples above demonstrate a common requirement of finding controls that have a specific name.  FindName will often not find these controls because they exist in a different namescope. Hope you find this useful, if not I’m just glad to be able to link to this blog in future stackoverflow answers.

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  • Think before you animate

    - by David Paquette
    Animations are becoming more and more common in our applications.  With technologies like WPF, Silverlight and jQuery, animations are becoming easier for developers to use (and abuse).  When used properly, animation can augment the user experience.  When used improperly, animation can degrade the user experience.  Sometimes, the differences can be very subtle. I have recently made use of animations in a few projects and I very quickly realized how easy it is to abuse animation techniques.  Here are a few things I have learned along the way. 1) Don’t animate for the sake of animating We’ve all seen the PowerPoint slides with annoying slide transitions that animate 20 different ways.  It’s distracting and tacky.  The same holds true for your application.  While animations are fun and becoming easy to implement, resist the urge to use the technology just because you think the technology is amazing.   2) Animations should (and do) have meaning I recently built a simple Windows Phone 7 (WP7) application, Steeped (download it here).  The application has 2 pages.  The first page lists a number of tea types.  When the user taps on one of the tea types, the application navigates to the second page with information about that tea type and some options for the user to choose from.       One of the last things I did before submitting Steeped to the marketplace was add a page transition between the 2 pages.  I choose the Slide / Fade Out transition.  When the user selects a tea type, the main page slides to the left and fades out.  At the same time, the details page slides in from the right and fades in.  I tested it and thought it looked great so I submitted the app.  A few days later, I asked a friend to try the app.  He selected a tea type, and I was a little surprised by how he used the app.  When he wanted to navigate back to the main page, instead of pressing the back button on the phone, he tried to use a swiping gesture.  Of course, the swiping gesture did nothing because I had not implemented that feature.  After thinking about it for a while, I realized that the page transition I had chosen implied a particular behaviour.  As a user, if an action I perform causes an item (in this case the page) to move, then my expectation is that I should be able to move it back.  I have since added logic to handle the swipe gesture and I think the app flows much better now. When using animation, it pays to ask yourself:  What story does this animation tell my users?   3) Watch the replay Some animations might seem great initially but can get annoying over time.  When you use an animation in your application, make sure you try using it over and over again to make sure it doesn’t get annoying.  When I add an animation, I try watch it at least 25 times in a row.  After watching the animation repeatedly, I can make a more informed decision whether or not I should keep the animation.  Often, I end up shortening the length of the animations.   4) Don’t get in the users way An animation should never slow the user down.  When implemented properly, an animation can give a perceived bump in performance.  A good example of this is a the page transitions in most of the built in apps on WP7.  Obviously, these page animations don’t make the phone any faster, but they do provide a more responsive user experience.  Why?  Because most of the animations begin as soon as the user has performed some action.  The destination page might not be fully loaded yet, but the system responded immediately to user action, giving the impression that the system is more responsive.  If the user did not see anything happen until after the destination page was fully loaded, the application would feel clumsy and slow.  Also, it is important to make sure the animation does not degrade the performance (or perceived performance) of the application.   Jut a few things to consider when using animations.  As is the case with many technologies, we often learn how to misuse it before we learn how to use it effectively.

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  • Finding it Hard to Deliver Right Customer Experience: Think BPM!

    - by Ajay Khanna
    Our relationship with our customers is not a just a single interaction and we should not treat it like one. A customer’s relationship with a vendor is like a journey which starts way before customer makes a purchase and lasts long after that. The journey may start with customer researching a product that may lead to the eventual purchase and may continue with support or service needs for the product. A typical customer journey can be represented as shown below: As you may notice, customers tend to use multiple channels to interact with a company throughout their journey.  They also expect that they should get consistent experience, no matter what interaction channel they may choose. Customers do not like to repeat the information they have already provided and expect companies to remember their preferences, and offer them relevant products and services. If the company fails to meet this expectation, customers not only will abandon the purchase and go to the competitor but may also influence others’ purchase decision. Gone are the days when word of mouth was the only medium, and the customer could influence “Six” others. This is the age of social media and customer’s good or bad experience, especially bad get highly amplified and may influence hundreds of others. Challenges that face B2C companies today include: Delivering consistent experience: The reason that delivering consistent experience is challenging is due to fragmented data, disjointed systems and siloed multichannel interactions. Customers tend to get different service quality if they use web vs. phone vs. store. They get different responses from different service agents or get inconsistent answers if they call sales vs. service group in the company. Such inconsistent experiences result in lower customer satisfaction or NPS (net promoter score) numbers. Increasing Revenue: To stay competitive companies frequently introduce new products and services. Delay in launching such offerings has a significant impact on revenue realization. In addition to new product revenue, there are multiple opportunities to up-sell and cross-sell that impact bottom line. If companies are not able to identify such opportunities, bring a product to market quickly, or not offer the right product to the right customer at the right time, significant loss of revenue may occur. Ensuring Compliance: Companies must be compliant to ever changing regulations, these could be about Know Your Customer (KYC), Export/Import regulations, or taxation policies. In addition to government agencies, companies also need to comply with the SLA that they have committed to their customers. Lapse in meeting any of these requirements may lead to serious fines, penalties and loss in business. Companies have to make sure that they are in compliance will all such regulations and SLA commitments, at any given time. With the advent of social networks and mobile technology, companies not only need to focus on process efficiency but also on customer engagement. Improving engagement means delivering the customer experience as the customer is expecting and interacting with the customer at right time using right channel. Customers expect to be able to contact you via any channel of their choice (web, email, chat, mobile, social media), purchase via any viable channel (web, phone, store, mobile). Customers expect companies to understand their particular needs and remember their preferences on repeated visits. To deliver such an integrated, consistent, and contextual experience, power of BPM in must. Your company may be organized in departments like Marketing, Sales, Service. You may hold prospect data in SFA, order information in ERP, customer issues in CRM. However, the experience delivered to the customer must not be constrained by your system legacy. BPM helps in designing the right experience for the right customer and integrates all the underlining channels, systems, applications to make sure right information will be delivered to the right knowledge worker or to the customer every single time.     Orchestrating information across all systems (MDM, CRM, ERP), departments (commerce, merchandising, marketing service) and channels (Email, phone, web, social)  is the key, and that’s what BPM delivers. In addition to orchestrating systems and channels for consistency, BPM also provides an ability for analysis and decision management. By using data from historical transactions, social media and from other systems, users can determine the customer preferences, customer value, and churn propensity. This information, in the context, is then used while making a decision at a process step. Working with real-time decision management system can also suggest right up-sell or cross-sell offers, discounts or next-best-action steps for a particular customer. Timely action on customer issues or request is also a key tenet of a good customer experience. BPM’s complex event processing capabilities help companies to take proactive actions before issues get escalated. BPM system can be designed to listen to a certain event patters then deduce from those customer situations (credit card stolen, baggage lost, change of address) and do a triage before situation goes out of control. If such a situation arises you can send alerts to right people or immediately invoke corrective actions. Last but not least one of BPM’s key values is to drive continuous improvement. Learning about customers past experiences, interactions and social conversations, provide valuable insight. Such insight can be used to improve products, customer facing processes, and customer experience. You may take these insights as an input to design better more efficient and customer friendly sales, contact center or self-service processes. If customer experience is important for your business, make sure you have incorporated BPM as a part of your strategy to design, orchestrate and improve your customer facing processes.

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  • What is Happening vs. What is Interesting

    - by Geertjan
    Devoxx 2011 was yet another confirmation that all development everywhere is either on the web or on mobile phones. Whether you looked at the conference schedule or attended sessions or talked to speakers at any point at all, it was very clear that no development whatsoever is done anymore on the desktop. In fact, that's something Tim Bray himself told me to my face at the speakers dinner. No new developments of any kind are happening on the desktop. Everyone who is currently on the desktop is working overtime to move all of their applications to the web. They're probably also creating a small subset of their application on an Android tablet, with an even smaller subset on their Android phone. Then you scratch that monolithic surface and find some interesting results. Without naming any names, I asked one of these prominent "ah, forget about the desktop" people at the Devoxx speakers dinner (and I have a witness): "Yes, the desktop is dead, but what about air traffic control, stock trading, oil analysis, risk management applications? In fact, what about any back office application that needs to be usable across all operating systems? Here there is no concern whatsoever with 100% accessibility which is, after all, the only thing that the web has over the desktop, (except when there's a network failure, of course, or when you find yourself in the 3/4 of the world where there's bandwidth problems)? There are 1000's of hidden applications out there that have processing requirements, security requirements, and the requirement that they'll be available even when the network is down or even completely unavailable. Isn't that a valid use case and aren't there 1000's of applications that fall into this so-called niche category? Are you not, in fact, confusing consumer applications, which are increasingly web-based and mobile-based, with high-end corporate applications, which typically need to do massive processing, of one kind or another, for which the web and mobile worlds are completely unsuited?" And you will not believe what the reply to the above question was. (Again, I have a witness to this discussion.) But here it is: "Yes. But those applications are not interesting. I do not want to spend any of my time or work in any way on those applications. They are boring." I'm sad to say that the leaders of the software development community, including those in the Java world, either share the above opinion or are led by it. Because they find something that is not new to be boring, they move on to what is interesting and start talking like the supposedly-boring developments don't even exist. (Kind of like a rapper pretending classical music doesn't exist.) Time and time again I find myself giving Java desktop development courses (at companies, i.e., not hobbyists, or students, but companies, i.e., the places where dollars are earned), where developers say to me: "The course you're giving about creating cross-platform, loosely coupled, and highly cohesive applications is really useful to us. Why do we never find information about this topic at conferences? Why can we never attend a session at a conference where the story about pluggable cross-platform Java is told? Why do we get the impression that we are uncool because we're not on the web and because we're not on a mobile phone, while the reason for that is because we're creating $1000,000 simulation software which has nothing to gain from being on the web or on the mobile phone?" And then I say: "Because nobody knows you exist. Because you're not submitting abstracts to conferences about your very interesting use cases. And because conferences tend to focus on what is new, which tends to be web related (especially HTML 5) or mobile related (especially Android). Because you're not taking the responsibility on yourself to tell the real stories about the real applications being developed all the time and every day. Because you yourself think your work is boring, while in fact it is fascinating. Because desktop developers are working from 9 to 5 on the desktop, in secure environments, such as banks and defense, where you can't spend time, nor have the interest in, blogging your latest tip or trick, as opposed to web developers, who tend to spend a lot of time on the web anyway and are therefore much more inclined to create buzz about the kind of work they're doing." So, next time you look at a conference program and wonder why there's no stories about large desktop development projects in the program, here's the short answer: "No one is going to put those items on the program until you start submitting those kinds of sessions. And until you start blogging. Until you start creating the buzz that the web developers have been creating around their work for the past 10 years or so. And, yes, indeed, programmers get the conference they deserve." And what about Tim Bray? Ask yourself, as Google's lead web technology evangelist, how many desktop developers do you think he talks to and, more generally, what his frame of reference is and what, clearly, he considers to be most interesting.

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  • Building Enterprise Smartphone App &ndash; Part 2: Platforms and Features

    - by Tim Murphy
    This is part 2 in a series of posts based on a talk I gave recently at the Chicago Information Technology Architects Group.  Feel free to leave feedback. In the previous post I discussed what reasons a company might have for creating a smartphone application.  In this installment I will cover some of history and state of the different platforms as well as features that can be leveraged for building enterprise smartphone applications. Platforms Before you start choosing a platform to develop your solutions on it is good to understand how we got here and what features you can leverage. History To my memory we owe all of this to a product called the Apple Newton that came out in 1987. It was the first PDA and back then I was much more of an Apple fan.  I was very impressed with this device even though it never really went anywhere.  The Palm Pilot by US Robotics was the next major advancement in PDA. It had a simple short hand window that allowed for quick stylus entry.. Later, Windows CE came out and started the broadening of the PDA market. After that it was the Palm and CE operating systems that started showing up on cell phones and for some time these were the two dominant operating systems that were distributed with devices from multiple hardware vendors. Current The iPhone was the first smartphone to take away the stylus and give us a multi-touch interface.  It was a revolution in usability and really changed the attractiveness of smartphones for the general public.  This brought us to the beginning of the current state of the market with the concept of an online store that makes it easy for customers to get new features and functionality on demand. With Android, Google made this more than a one horse race.  Not only did they come to compete, their low cost actually made them the leading OS.  Of course what made Android so attractive also is its major fault.  It is so open that it has been a target for malware which leaves consumers exposed.  Fortunately for Google though, most consumers aren’t aware of the threat that they are under. Although Microsoft had put out one of the first smart phone operating systems with CE it had to play catch up and finally came out with the Windows Phone.  They have gone for a market approach between those of iOS and Android.  They support multiple hardware vendors like Google, but they kept a certification process for applications that is similar to Apple.  They also created a user interface that was different enough to give it a clear separation from the other two platforms. The result of all this is hundreds of millions of smartphones being sold monthly across all three platforms giving us a wide range of choices and challenges when it comes to developing solutions. Features So what are the features that make these devices flexible enough be considered for use in the enterprise? The biggest advantage of today's devices is network connectivity.  The ability to access information from multiple sources at a moment’s notice is critical for businesses.  Add to that the ability to communicate over a variety of text, voice and video modes and we have a powerful starting point. Every smartphone has a cameras and they are not just useful for posting to Instagram. We are seeing more applications such as Bing vision that allow us to scan just about any printed code or text to find information.  These capabilities have been made available to developers in the form of standard libraries for reading barcodes of just about an flavor and optical character recognition (OCR) interpretation. Bluetooth give us the ability to communicate with multiple devices. Whether these are headsets, keyboard or printers the wireless communication capabilities are just starting to evolve.  The more these wireless communication protocols grow, the more opportunities we will see to transfer data between users and a variety of devices. Local storage of information that can be called up even when the device cannot reach the network is the other big capability.  This give users the ability to work offline as well and transmit information when connections are restored. These are the tools that we have to work with to build applications that can be leveraged to gain a competitive advantage for companies that implement them. Coming Up In the third installment I will cover key concerns that you face when building enterprise smartphone apps. del.icio.us Tags: smartphones,enterprise smartphone Apps,architecture,iOS,Android,Windows Phone

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  • linux raid 1: right after replacing and syncing one drive, the other disk fails - understanding what is going on with mdstat/mdadm

    - by devicerandom
    We have an old RAID 1 Linux server (Ubuntu Lucid 10.04), with four partitions. A few days ago /dev/sdb failed, and today we noticed /dev/sda had pre-failure ominous SMART signs (~4000 reallocated sector count). We replaced /dev/sdb this morning and rebuilt the RAID on the new drive, following this guide: http://www.howtoforge.com/replacing_hard_disks_in_a_raid1_array Everything went smooth until the very end. When it looked like it was finishing to synchronize the last partition, the other old one failed. At this point I am very unsure of the state of the system. Everything seems working and the files seem to be all accessible, just as if it synchronized everything, but I'm new to RAID and I'm worried about what is going on. The /proc/mdstat output is: Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] md3 : active raid1 sdb4[2](S) sda4[0] 478713792 blocks [2/1] [U_] md2 : active raid1 sdb3[1] sda3[2](F) 244140992 blocks [2/1] [_U] md1 : active raid1 sdb2[1] sda2[2](F) 244140992 blocks [2/1] [_U] md0 : active raid1 sdb1[1] sda1[2](F) 9764800 blocks [2/1] [_U] unused devices: <none> The order of [_U] vs [U_]. Why aren't they consistent along all the array? Is the first U /dev/sda or /dev/sdb? (I tried looking on the web for this trivial information but I found no explicit indication) If I read correctly for md0, [_U] should be /dev/sda1 (down) and /dev/sdb1 (up). But if /dev/sda has failed, how can it be the opposite for md3 ? I understand /dev/sdb4 is now spare because probably it failed to synchronize it 100%, but why does it show /dev/sda4 as up? Shouldn't it be [__]? Or [_U] anyway? The /dev/sda drive now cannot even be accessed by SMART anymore apparently, so I wouldn't expect it to be up. What is wrong with my interpretation of the output? I attach also the outputs of mdadm --detail for the four partitions: /dev/md0: Version : 00.90 Creation Time : Fri Jan 21 18:43:07 2011 Raid Level : raid1 Array Size : 9764800 (9.31 GiB 10.00 GB) Used Dev Size : 9764800 (9.31 GiB 10.00 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 0 Persistence : Superblock is persistent Update Time : Tue Nov 5 17:27:33 2013 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 UUID : a3b4dbbd:859bf7f2:bde36644:fcef85e2 Events : 0.7704 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 17 1 active sync /dev/sdb1 2 8 1 - faulty spare /dev/sda1 /dev/md1: Version : 00.90 Creation Time : Fri Jan 21 18:43:15 2011 Raid Level : raid1 Array Size : 244140992 (232.83 GiB 250.00 GB) Used Dev Size : 244140992 (232.83 GiB 250.00 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 1 Persistence : Superblock is persistent Update Time : Tue Nov 5 17:39:06 2013 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 UUID : 8bcd5765:90dc93d5:cc70849c:224ced45 Events : 0.1508280 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 18 1 active sync /dev/sdb2 2 8 2 - faulty spare /dev/sda2 /dev/md2: Version : 00.90 Creation Time : Fri Jan 21 18:43:19 2011 Raid Level : raid1 Array Size : 244140992 (232.83 GiB 250.00 GB) Used Dev Size : 244140992 (232.83 GiB 250.00 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 2 Persistence : Superblock is persistent Update Time : Tue Nov 5 17:46:44 2013 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 UUID : 2885668b:881cafed:b8275ae8:16bc7171 Events : 0.2289636 Number Major Minor RaidDevice State 0 0 0 0 removed 1 8 19 1 active sync /dev/sdb3 2 8 3 - faulty spare /dev/sda3 /dev/md3: Version : 00.90 Creation Time : Fri Jan 21 18:43:22 2011 Raid Level : raid1 Array Size : 478713792 (456.54 GiB 490.20 GB) Used Dev Size : 478713792 (456.54 GiB 490.20 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 3 Persistence : Superblock is persistent Update Time : Tue Nov 5 17:19:20 2013 State : clean, degraded Active Devices : 1 Working Devices : 2 Failed Devices : 0 Spare Devices : 1 Number Major Minor RaidDevice State 0 8 4 0 active sync /dev/sda4 1 0 0 1 removed 2 8 20 - spare /dev/sdb4 The active sync on /dev/sda4 baffles me. I am worried because if tomorrow morning I have to replace /dev/sda, I want to be sure what should I sync with what and what is going on. I am also quite baffled by the fact /dev/sda decided to fail exactly when the raid finished resyncing. I'd like to understand what is really happening. Thanks a lot for your patience and help. Massimo

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  • Apache Getting Bogged Down By Certain Script (Wp-Cron.php) - How To Kill Process Automatically

    - by user50037
    I have a server that is running a number of wordpress blogs, and a number of them have several hundred/thousand posts. Every couple of days, the server slows to a crawl due to a file being run on Wordpress called WP-cron.php. My entire apache process log turns into this : http:// imgur.com/A7K9k.png Times that by quite a bit. And server no go. Each process takes up about 1.1% of ram. And when we have 50 of them on the go. It gets insane. Not all of them are coming from the same blog, they are pretty widespread. In the Apache process page of WHM, they are usually ALL set to the status of "C", which means closing. But they can sit there until they crash the server, and they still hold the memory. Just google "wp-cron.php load" and you will find plenty of people with similar issues. In anycase, we have think it is down to users adding a tonne of dead "pinglists" to their wordpress installation. Which in turn wordpress loops through them endlessly. Problem number 1. Does anyone have any other suggestions about what would cause the Wordpress file wp-cron.php to loop endlessly. I still think it is down to pings, because all of the people we have contacted about their account load going sky high, have had massive ping lists. Problem number 2. Even if it is down to excessive pinglists in wordpress. We cannot be babying every single account on the server waiting for it to start spawning the wp-cron processes. It often happens overnight, and I start getting SMS alerts at 2am about the load. I have CSF installed, which apparently would have ended the processes if they ran over XXX time. But I have been told that it won't catch the processes because they end up in this state of "closing" (They show up as "C" on the Apache page of WHM). Apparently CSF will only kill processes that are "running" which C does not count. I have seen various other scripts such as : http://dltj.org/article/die-apache-die/ . I took a look at the stat of /proc. But I was boggled at which delimited part was the time running. And if there was any way I could connect it back to an actual Apache process, so that I could see what file was running (So only close connections connected to wp-cron.php, with a state of "C"). Overall I know Problem 2 glosses over the real reason. But I do put the whole thing to excessive pinglists in Wordpress. But I just cannot sit there and babysit every single installation 24/7. So I need a way to save the server when I am not available. Any help would be much appreciated.

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  • Failing Sata HDD

    - by DaveCol
    I think my HDD is fried... Could someone confirm or help me restore it? I was using Hardware RAID 1 Configuration [2 x 160GB SATA HDD] on a CentOS 4 Installation. All of a sudden I started seeing bad sectors on the second HDD which stopped being mirrored. I have removed the RAID array and have tested with SMART which showed the following error: 187 Unknown_Attribute 0x003a 001 001 051 Old_age Always FAILING_NOW 4645 I have no clue what this means, or if I can recover from it. Could someone give me some ideas on how to fix this, or what HDD to get to replace this? Complete SMART report: Smartctl version 5.33 [i686-redhat-linux-gnu] Copyright (C) 2002-4 Bruce Allen Home page is http://smartmontools.sourceforge.net/ === START OF INFORMATION SECTION === Device Model: GB0160CAABV Serial Number: 6RX58NAA Firmware Version: HPG1 User Capacity: 160,041,885,696 bytes Device is: Not in smartctl database [for details use: -P showall] ATA Version is: 7 ATA Standard is: ATA/ATAPI-7 T13 1532D revision 4a Local Time is: Tue Oct 19 13:42:42 2010 COT SMART support is: Available - device has SMART capability. SMART support is: Enabled === START OF READ SMART DATA SECTION === SMART overall-health self-assessment test result: PASSED See vendor-specific Attribute list for marginal Attributes. General SMART Values: Offline data collection status: (0x82) Offline data collection activity was completed without error. Auto Offline Data Collection: Enabled. Self-test execution status: ( 0) The previous self-test routine completed without error or no self-test has ever been run. Total time to complete Offline data collection: ( 433) seconds. Offline data collection capabilities: (0x5b) SMART execute Offline immediate. Auto Offline data collection on/off support. Suspend Offline collection upon new command. Offline surface scan supported. Self-test supported. No Conveyance Self-test supported. Selective Self-test supported. SMART capabilities: (0x0003) Saves SMART data before entering power-saving mode. Supports SMART auto save timer. Error logging capability: (0x01) Error logging supported. General Purpose Logging supported. Short self-test routine recommended polling time: ( 2) minutes. Extended self-test routine recommended polling time: ( 54) minutes. SMART Attributes Data Structure revision number: 10 Vendor Specific SMART Attributes with Thresholds: ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE 1 Raw_Read_Error_Rate 0x000f 100 253 006 Pre-fail Always - 0 3 Spin_Up_Time 0x0002 097 097 000 Old_age Always - 0 4 Start_Stop_Count 0x0033 100 100 020 Pre-fail Always - 152 5 Reallocated_Sector_Ct 0x0033 095 095 036 Pre-fail Always - 214 7 Seek_Error_Rate 0x000f 078 060 030 Pre-fail Always - 73109713 9 Power_On_Hours 0x0032 083 083 000 Old_age Always - 15133 10 Spin_Retry_Count 0x0013 100 100 097 Pre-fail Always - 0 12 Power_Cycle_Count 0x0033 100 100 020 Pre-fail Always - 154 184 Unknown_Attribute 0x0032 038 038 000 Old_age Always - 62 187 Unknown_Attribute 0x003a 001 001 051 Old_age Always FAILING_NOW 4645 189 Unknown_Attribute 0x0022 100 100 000 Old_age Always - 0 190 Unknown_Attribute 0x001a 061 055 000 Old_age Always - 656408615 194 Temperature_Celsius 0x0000 039 045 000 Old_age Offline - 39 (Lifetime Min/Max 0/22) 195 Hardware_ECC_Recovered 0x0032 070 059 000 Old_age Always - 12605265 197 Current_Pending_Sector 0x0000 100 100 000 Old_age Offline - 1 198 Offline_Uncorrectable 0x0000 100 100 000 Old_age Offline - 0 199 UDMA_CRC_Error_Count 0x0000 200 200 000 Old_age Offline - 62 SMART Error Log Version: 1 ATA Error Count: 4645 (device log contains only the most recent five errors) CR = Command Register [HEX] FR = Features Register [HEX] SC = Sector Count Register [HEX] SN = Sector Number Register [HEX] CL = Cylinder Low Register [HEX] CH = Cylinder High Register [HEX] DH = Device/Head Register [HEX] DC = Device Command Register [HEX] ER = Error register [HEX] ST = Status register [HEX] Powered_Up_Time is measured from power on, and printed as DDd+hh:mm:SS.sss where DD=days, hh=hours, mm=minutes, SS=sec, and sss=millisec. It "wraps" after 49.710 days. Error 4645 occurred at disk power-on lifetime: 15132 hours (630 days + 12 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 51 00 7b 86 b1 ea Error: UNC at LBA = 0x0ab1867b = 179406459 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 02 7b 86 b1 ea 00 00:38:52.796 READ DMA ec 03 45 00 00 00 a0 00 00:38:52.796 IDENTIFY DEVICE ef 03 45 00 00 00 a0 00 00:38:52.794 SET FEATURES [Set transfer mode] ec 00 00 7b 86 b1 a0 00 00:38:49.991 IDENTIFY DEVICE c8 00 04 79 86 b1 ea 00 00:38:49.935 READ DMA Error 4644 occurred at disk power-on lifetime: 15132 hours (630 days + 12 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 51 00 7b 86 b1 ea Error: UNC at LBA = 0x0ab1867b = 179406459 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 04 79 86 b1 ea 00 00:38:41.517 READ DMA ec 03 45 00 00 00 a0 00 00:38:41.515 IDENTIFY DEVICE ef 03 45 00 00 00 a0 00 00:38:41.515 SET FEATURES [Set transfer mode] ec 00 00 7b 86 b1 a0 00 00:38:49.991 IDENTIFY DEVICE c8 00 06 77 86 b1 ea 00 00:38:49.935 READ DMA Error 4643 occurred at disk power-on lifetime: 15132 hours (630 days + 12 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 51 00 7b 86 b1 ea Error: UNC at LBA = 0x0ab1867b = 179406459 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 06 77 86 b1 ea 00 00:38:41.517 READ DMA ec 03 45 00 00 00 a0 00 00:38:41.515 IDENTIFY DEVICE ef 03 45 00 00 00 a0 00 00:38:41.515 SET FEATURES [Set transfer mode] ec 00 00 7b 86 b1 a0 00 00:38:41.513 IDENTIFY DEVICE c8 00 06 77 86 b1 ea 00 00:38:38.706 READ DMA Error 4642 occurred at disk power-on lifetime: 15132 hours (630 days + 12 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 51 00 7b 86 b1 ea Error: UNC at LBA = 0x0ab1867b = 179406459 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 06 77 86 b1 ea 00 00:38:41.517 READ DMA ec 03 45 00 00 00 a0 00 00:38:41.515 IDENTIFY DEVICE ef 03 45 00 00 00 a0 00 00:38:41.515 SET FEATURES [Set transfer mode] ec 00 00 7b 86 b1 a0 00 00:38:41.513 IDENTIFY DEVICE c8 00 06 77 86 b1 ea 00 00:38:38.706 READ DMA Error 4641 occurred at disk power-on lifetime: 15132 hours (630 days + 12 hours) When the command that caused the error occurred, the device was active or idle. After command completion occurred, registers were: ER ST SC SN CL CH DH -- -- -- -- -- -- -- 40 51 00 7b 86 b1 ea Error: UNC at LBA = 0x0ab1867b = 179406459 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- c8 00 06 77 86 b1 ea 00 00:38:41.517 READ DMA ec 03 45 00 00 00 a0 00 00:38:41.515 IDENTIFY DEVICE ef 03 45 00 00 00 a0 00 00:38:41.515 SET FEATURES [Set transfer mode] ec 00 00 7b 86 b1 a0 00 00:38:41.513 IDENTIFY DEVICE c8 00 06 77 86 b1 ea 00 00:38:38.706 READ DMA SMART Self-test log structure revision number 1 Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error # 1 Short offline Completed without error 00% 15131 - # 2 Short offline Completed without error 00% 15131 - SMART Selective self-test log data structure revision number 1 SPAN MIN_LBA MAX_LBA CURRENT_TEST_STATUS 1 0 0 Not_testing 2 0 0 Not_testing 3 0 0 Not_testing 4 0 0 Not_testing 5 0 0 Not_testing Selective self-test flags (0x0): After scanning selected spans, do NOT read-scan remainder of disk. If Selective self-test is pending on power-up, resume after 0 minute delay.

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  • How To Activate Your Free Office 2007 to 2010 Tech Guarantee Upgrade

    - by Matthew Guay
    Have you purchased Office 2007 since March 5th, 2010?  If so, here’s how you can activate and download your free upgrade to Office 2010! Microsoft Office 2010 has just been released, and today you can purchase upgrades from most retail stores or directly from Microsoft via download.  But if you’ve purchased a new copy of Office 2007 or a new computer that came with Office 2007 since March 5th, 2010, then you’re entitled to an absolutely free upgrade to Office 2010.  You’ll need enter information about your Office 2007 and then download the upgrade, so we’ll step you through the process. Getting Started First, if you’ve recently purchased Office 2007 but haven’t installed it, you’ll need to go ahead and install it before you can get your free Office 2010 upgrade.  Install it as normal.   Once Office 2007 is installed, run any of the Office programs.  You’ll be prompted to activate Office.  Make sure you’re connected to the internet, and then click Next to activate. Get your Free Upgrade to Office 2010 Now you’re ready to download your upgrade to Office 2010.  Head to the Office Tech Guarantee site (link below), and click Upgrade now. You’ll need to enter some information about your Office 2007.  Check that you purchased your copy of Office 2007 after March 5th, select your computer manufacturer, and check that you agree to the terms. Now you’re going to need the Product ID number from Office 2007.  To find this, open Word or any other Office 2007 application.  Click the Office Orb, and select Options on the bottom. Select the Resources button on the left, and then click About. Near the bottom of this dialog, you’ll see your Product ID.  This should be a number like: 12345-123-1234567-12345   Go back to the Office Tech Guarantee signup page in your browser, and enter this Product ID.  Select the language of your edition of Office 2007, enter the verification code, and then click Submit. It may take a few moments to validate your Product ID. When it is finished, you’ll be taken to an order page that shows the edition of Office 2010 you’re eligible to receive.  The upgrade download is free, but if you’d like to purchase a backup DVD of Office 2010, you can add it to your order for $13.99.  Otherwise, simply click Continue to accept. Do note that the edition of Office 2010 you receive may be different that the edition of Office 2007 you purchased, as the number of editions has been streamlined in the Office 2010 release.  Here’s a chart you can check to see what edition you’ll receive.  Note that you’ll still be allowed to install Office on the same number of computers; for example, Office 2007 Home and Student allows you to install it on up to 3 computers in the same house, and your Office 2010 upgrade will allow the same. Office 2007 Edition Office 2010 Upgrade You’ll Receive Office 2007 Home and Student Office Home and Student 2010 Office Basic 2007Office Standard 2007 Office Home and Business 2010 Office Small Business 2007Office Professional 2007Office Ultimate 2007 Office Professional 2010 Office Professional 2007 AcademicOffice Ultimate 2007 Academic Office Professional Academic 2010 Sign in with your Windows Live ID, or create a new one if you don’t already have one. Enter your name, select your country, and click Create My Account.  Note that Office will send Office 2010 tips to your email address; if you don’t wish to receive them, you can unsubscribe from the emails later.   Finally, you’re ready to download Office 2010!  Click the Download Now link to start downloading Office 2010.  Your Product Key will appear directly above the Download link, so you can copy it and then paste it in the installer when your download is finished.  You will additionally receive an email with the download links and product key, so if your download fails you can always restart it from that link. If your edition of Office 2007 included the Office Business Contact Manager, you will be able to download it from the second Download link.  And, of course, even if you didn’t order a backup DVD, you can always burn the installers to a DVD for a backup.   Install Office 2010 Once you’re finished downloading Office 2010, run the installer to get it installed on your computer.  Enter your Product Key from the Tech Guarantee website as above, and click Continue. Accept the license agreement, and then click Upgrade to upgrade to the latest version of Office.   The installer will remove all of your Office 2007 applications, and then install their 2010 counterparts.  If you wish to keep some of your Office 2007 applications instead, click Customize and then select to either keep all previous versions or simply keep specific applications. By default, Office 2010 will try to activate online automatically.  If it doesn’t activate during the install, you’ll need to activate it when you first run any of the Office 2010 apps.   Conclusion The Tech Guarantee makes it easy to get the latest version of Office if you recently purchased Office 2007.  The Tech Guarantee program is open through the end of September, so make sure to grab your upgrade during this time.  Actually, if you find a great deal on Office 2007 from a major retailer between now and then, you could also take advantage of this program to get Office 2010 cheaper. And if you need help getting started with Office 2010, check out our articles that can help you get situated in your new version of Office! Link Activate and Download Your free Office 2010 Tech Guarantee Upgrade Similar Articles Productive Geek Tips Remove Office 2010 Beta and Reinstall Office 2007Upgrade Office 2003 to 2010 on XP or Run them Side by SideCenter Pictures and Other Objects in Office 2007 & 2010Change the Default Color Scheme in Office 2010Show Two Time Zones in Your Outlook 2007 Calendar TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips HippoRemote Pro 2.2 Xobni Plus for Outlook All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Windows Media Player Plus! – Cool WMP Enhancer Get Your Team’s World Cup Schedule In Google Calendar Backup Drivers With Driver Magician TubeSort: YouTube Playlist Organizer XPS file format & XPS Viewer Explained Microsoft Office Web Apps Guide

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  • C# 4: The Curious ConcurrentDictionary

    - by James Michael Hare
    In my previous post (here) I did a comparison of the new ConcurrentQueue versus the old standard of a System.Collections.Generic Queue with simple locking.  The results were exactly what I would have hoped, that the ConcurrentQueue was faster with multi-threading for most all situations.  In addition, concurrent collections have the added benefit that you can enumerate them even if they're being modified. So I set out to see what the improvements would be for the ConcurrentDictionary, would it have the same performance benefits as the ConcurrentQueue did?  Well, after running some tests and multiple tweaks and tunes, I have good and bad news. But first, let's look at the tests.  Obviously there's many things we can do with a dictionary.  One of the most notable uses, of course, in a multi-threaded environment is for a small, local in-memory cache.  So I set about to do a very simple simulation of a cache where I would create a test class that I'll just call an Accessor.  This accessor will attempt to look up a key in the dictionary, and if the key exists, it stops (i.e. a cache "hit").  However, if the lookup fails, it will then try to add the key and value to the dictionary (i.e. a cache "miss").  So here's the Accessor that will run the tests: 1: internal class Accessor 2: { 3: public int Hits { get; set; } 4: public int Misses { get; set; } 5: public Func<int, string> GetDelegate { get; set; } 6: public Action<int, string> AddDelegate { get; set; } 7: public int Iterations { get; set; } 8: public int MaxRange { get; set; } 9: public int Seed { get; set; } 10:  11: public void Access() 12: { 13: var randomGenerator = new Random(Seed); 14:  15: for (int i=0; i<Iterations; i++) 16: { 17: // give a wide spread so will have some duplicates and some unique 18: var target = randomGenerator.Next(1, MaxRange); 19:  20: // attempt to grab the item from the cache 21: var result = GetDelegate(target); 22:  23: // if the item doesn't exist, add it 24: if(result == null) 25: { 26: AddDelegate(target, target.ToString()); 27: Misses++; 28: } 29: else 30: { 31: Hits++; 32: } 33: } 34: } 35: } Note that so I could test different implementations, I defined a GetDelegate and AddDelegate that will call the appropriate dictionary methods to add or retrieve items in the cache using various techniques. So let's examine the three techniques I decided to test: Dictionary with mutex - Just your standard generic Dictionary with a simple lock construct on an internal object. Dictionary with ReaderWriterLockSlim - Same Dictionary, but now using a lock designed to let multiple readers access simultaneously and then locked when a writer needs access. ConcurrentDictionary - The new ConcurrentDictionary from System.Collections.Concurrent that is supposed to be optimized to allow multiple threads to access safely. So the approach to each of these is also fairly straight-forward.  Let's look at the GetDelegate and AddDelegate implementations for the Dictionary with mutex lock: 1: var addDelegate = (key,val) => 2: { 3: lock (_mutex) 4: { 5: _dictionary[key] = val; 6: } 7: }; 8: var getDelegate = (key) => 9: { 10: lock (_mutex) 11: { 12: string val; 13: return _dictionary.TryGetValue(key, out val) ? val : null; 14: } 15: }; Nothing new or fancy here, just your basic lock on a private object and then query/insert into the Dictionary. Now, for the Dictionary with ReadWriteLockSlim it's a little more complex: 1: var addDelegate = (key,val) => 2: { 3: _readerWriterLock.EnterWriteLock(); 4: _dictionary[key] = val; 5: _readerWriterLock.ExitWriteLock(); 6: }; 7: var getDelegate = (key) => 8: { 9: string val; 10: _readerWriterLock.EnterReadLock(); 11: if(!_dictionary.TryGetValue(key, out val)) 12: { 13: val = null; 14: } 15: _readerWriterLock.ExitReadLock(); 16: return val; 17: }; And finally, the ConcurrentDictionary, which since it does all it's own concurrency control, is remarkably elegant and simple: 1: var addDelegate = (key,val) => 2: { 3: _concurrentDictionary[key] = val; 4: }; 5: var getDelegate = (key) => 6: { 7: string s; 8: return _concurrentDictionary.TryGetValue(key, out s) ? s : null; 9: };                    Then, I set up a test harness that would simply ask the user for the number of concurrent Accessors to attempt to Access the cache (as specified in Accessor.Access() above) and then let them fly and see how long it took them all to complete.  Each of these tests was run with 10,000,000 cache accesses divided among the available Accessor instances.  All times are in milliseconds. 1: Dictionary with Mutex Locking 2: --------------------------------------------------- 3: Accessors Mostly Misses Mostly Hits 4: 1 7916 3285 5: 10 8293 3481 6: 100 8799 3532 7: 1000 8815 3584 8:  9:  10: Dictionary with ReaderWriterLockSlim Locking 11: --------------------------------------------------- 12: Accessors Mostly Misses Mostly Hits 13: 1 8445 3624 14: 10 11002 4119 15: 100 11076 3992 16: 1000 14794 4861 17:  18:  19: Concurrent Dictionary 20: --------------------------------------------------- 21: Accessors Mostly Misses Mostly Hits 22: 1 17443 3726 23: 10 14181 1897 24: 100 15141 1994 25: 1000 17209 2128 The first test I did across the board is the Mostly Misses category.  The mostly misses (more adds because data requested was not in the dictionary) shows an interesting trend.  In both cases the Dictionary with the simple mutex lock is much faster, and the ConcurrentDictionary is the slowest solution.  But this got me thinking, and a little research seemed to confirm it, maybe the ConcurrentDictionary is more optimized to concurrent "gets" than "adds".  So since the ratio of misses to hits were 2 to 1, I decided to reverse that and see the results. So I tweaked the data so that the number of keys were much smaller than the number of iterations to give me about a 2 to 1 ration of hits to misses (twice as likely to already find the item in the cache than to need to add it).  And yes, indeed here we see that the ConcurrentDictionary is indeed faster than the standard Dictionary here.  I have a strong feeling that as the ration of hits-to-misses gets higher and higher these number gets even better as well.  This makes sense since the ConcurrentDictionary is read-optimized. Also note that I tried the tests with capacity and concurrency hints on the ConcurrentDictionary but saw very little improvement, I think this is largely because on the 10,000,000 hit test it quickly ramped up to the correct capacity and concurrency and thus the impact was limited to the first few milliseconds of the run. So what does this tell us?  Well, as in all things, ConcurrentDictionary is not a panacea.  It won't solve all your woes and it shouldn't be the only Dictionary you ever use.  So when should we use each? Use System.Collections.Generic.Dictionary when: You need a single-threaded Dictionary (no locking needed). You need a multi-threaded Dictionary that is loaded only once at creation and never modified (no locking needed). You need a multi-threaded Dictionary to store items where writes are far more prevalent than reads (locking needed). And use System.Collections.Concurrent.ConcurrentDictionary when: You need a multi-threaded Dictionary where the writes are far more prevalent than reads. You need to be able to iterate over the collection without locking it even if its being modified. Both Dictionaries have their strong suits, I have a feeling this is just one where you need to know from design what you hope to use it for and make your decision based on that criteria.

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  • AutoMapper MappingFunction from Source Type of NameValueCollection

    - by REA_ANDREW
    I have had a situation arise today where I need to construct a complex type from a source of a NameValueCollection.  A little while back I submitted a patch for the Agatha Project to include REST (JSON and XML) support for the service contract.  I realized today that as useful as it is, it did not actually support true REST conformance, as REST should support GET so that you can use JSONP from JavaScript directly meaning you can query cross domain services.  My original implementation for POX and JSON used the POST method and this immediately rules out JSONP as from reading, JSONP only works with GET Requests. This then raised another issue.  The current operation contract of Agatha and one of its main benefits is that you can supply an array of Request objects in a single request, limiting the about of server requests you need to make.  Now, at the present time I am thinking that this will not be the case for the REST imlementation but will yield the benefits of the fact that : The same Request objects can be used for SOAP and RST (POX, JSON) The construct of the JavaScript functions will be simpler and more readable It will enable the use of JSONP for cross domain REST Services The current contract for the Agatha WcfRequestProcessor is at time of writing the following: [ServiceContract] public interface IWcfRequestProcessor { [OperationContract(Name = "ProcessRequests")] [ServiceKnownType("GetKnownTypes", typeof(KnownTypeProvider))] [TransactionFlow(TransactionFlowOption.Allowed)] Response[] Process(params Request[] requests); [OperationContract(Name = "ProcessOneWayRequests", IsOneWay = true)] [ServiceKnownType("GetKnownTypes", typeof(KnownTypeProvider))] void ProcessOneWayRequests(params OneWayRequest[] requests); }   My current proposed solution, and at the very early stages of my concept is as follows: [ServiceContract] public interface IWcfRestJsonRequestProcessor { [OperationContract(Name="process")] [ServiceKnownType("GetKnownTypes", typeof(KnownTypeProvider))] [TransactionFlow(TransactionFlowOption.Allowed)] [WebGet(UriTemplate = "process/{name}/{*parameters}", BodyStyle = WebMessageBodyStyle.WrappedResponse, ResponseFormat = WebMessageFormat.Json)] Response[] Process(string name, NameValueCollection parameters); [OperationContract(Name="processoneway",IsOneWay = true)] [ServiceKnownType("GetKnownTypes", typeof(KnownTypeProvider))] [WebGet(UriTemplate = "process-one-way/{name}/{*parameters}", BodyStyle = WebMessageBodyStyle.WrappedResponse, ResponseFormat = WebMessageFormat.Json)] void ProcessOneWayRequests(string name, NameValueCollection parameters); }   Now this part I have not yet implemented, it is the preliminart step which I have developed which will allow me to take the name of the Request Type and the NameValueCollection and construct the complex type which is that of the Request which I can then supply to a nested instance of the original IWcfRequestProcessor  and work as it should normally.  To give an example of some of the urls which you I envisage with this method are: http://www.url.com/service.svc/json/process/getweather/?location=london http://www.url.com/service.svc/json/process/getproductsbycategory/?categoryid=1 http://www.url.om/service.svc/json/process/sayhello/?name=andy Another reason why my direction has gone to a single request for the REST implementation is because of restrictions which are imposed by browsers on the length of the url.  From what I have read this is on average 2000 characters.  I think that this is a very acceptable usage limit in the context of using 1 request, but I do not think this is acceptable for accommodating multiple requests chained together.  I would love to be corrected on that one, I really would but unfortunately from what I have read I have come to the conclusion that this is not the case. The mapping function So, as I say this is just the first pass I have made at this, and I am not overly happy with the try catch for detecting types without default constructors.  I know there is a better way but for the minute, it escapes me.  I would also like to know the correct way for adding mapping functions and not using the anonymous way that I have used.  To achieve this I have used recursion which I am sure is what other mapping function use. As you do have to go as deep as the complex type is. public static object RecurseType(NameValueCollection collection, Type type, string prefix) { try { var returnObject = Activator.CreateInstance(type); foreach (var property in type.GetProperties()) { foreach (var key in collection.AllKeys) { if (String.IsNullOrEmpty(prefix) || key.Length > prefix.Length) { var propertyNameToMatch = String.IsNullOrEmpty(prefix) ? key : key.Substring(property.Name.IndexOf(prefix) + prefix.Length + 1); if (property.Name == propertyNameToMatch) { property.SetValue(returnObject, Convert.ChangeType(collection.Get(key), property.PropertyType), null); } else if(property.GetValue(returnObject,null) == null) { property.SetValue(returnObject, RecurseType(collection, property.PropertyType, String.Concat(prefix, property.PropertyType.Name)), null); } } } } return returnObject; } catch (MissingMethodException) { //Quite a blunt way of dealing with Types without default constructor return null; } }   Another thing is performance, I have not measured this in anyway, it is as I say the first pass, so I hope this can be the start of a more perfected implementation.  I tested this out with a complex type of three levels, there is no intended logical meaning to the properties, they are simply for the purposes of example.  You could call this a spiking session, as from here on in, now I know what I am building I would take a more TDD approach.  OK, purists, why did I not do this from the start, well I didn’t, this was a brain dump and now I know what I am building I can. The console test and how I used with AutoMapper is as follows: static void Main(string[] args) { var collection = new NameValueCollection(); collection.Add("Name", "Andrew Rea"); collection.Add("Number", "1"); collection.Add("AddressLine1", "123 Street"); collection.Add("AddressNumber", "2"); collection.Add("AddressPostCodeCountry", "United Kingdom"); collection.Add("AddressPostCodeNumber", "3"); AutoMapper.Mapper.CreateMap<NameValueCollection, Person>() .ConvertUsing(x => { return(Person) RecurseType(x, typeof(Person), null); }); var person = AutoMapper.Mapper.Map<NameValueCollection, Person>(collection); Console.WriteLine(person.Name); Console.WriteLine(person.Number); Console.WriteLine(person.Address.Line1); Console.WriteLine(person.Address.Number); Console.WriteLine(person.Address.PostCode.Country); Console.WriteLine(person.Address.PostCode.Number); Console.ReadLine(); }   Notice the convention that I am using and that this method requires you do use.  Each property is prefixed with the constructed name of its parents combined.  This is the convention used by AutoMapper and it makes sense. I can also think of other uses for this including using with ASP.NET MVC ModelBinders for creating a complex type from the QueryString which is itself is a NameValueCollection. Hope this is of some help to people and I would welcome any code reviews you could give me. References: Agatha : http://code.google.com/p/agatha-rrsl/ AutoMapper : http://automapper.codeplex.com/   Cheers for now, Andrew   P.S. I will have the proposed solution for a more complete REST implementation for AGATHA very soon. 

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  • Reporting Services - It's a Wrap!

    - by smisner
    If you have any experience at all with Reporting Services, you have probably developed a report using the matrix data region. It's handy when you want to generate columns dynamically based on data. If users view a matrix report online, they can scroll horizontally to view all columns and all is well. But if they want to print the report, the experience is completely different and you'll have to decide how you want to handle dynamic columns. By default, when a user prints a matrix report for which the number of columns exceeds the width of the page, Reporting Services determines how many columns can fit on the page and renders one or more separate pages for the additional columns. In this post, I'll explain two techniques for managing dynamic columns. First, I'll show how to use the RepeatRowHeaders property to make it easier to read a report when columns span multiple pages, and then I'll show you how to "wrap" columns so that you can avoid the horizontal page break. Included with this post are the sample RDLs for download. First, let's look at the default behavior of a matrix. A matrix that has too many columns for one printed page (or output to page-based renderer like PDF or Word) will be rendered such that the first page with the row group headers and the inital set of columns, as shown in Figure 1. The second page continues by rendering the next set of columns that can fit on the page, as shown in Figure 2.This pattern continues until all columns are rendered. The problem with the default behavior is that you've lost the context of employee and sales order - the row headers - on the second page. That makes it hard for users to read this report because the layout requires them to flip back and forth between the current page and the first page of the report. You can fix this behavior by finding the RepeatRowHeaders of the tablix report item and changing its value to True. The second (and subsequent pages) of the matrix now look like the image shown in Figure 3. The problem with this approach is that the number of printed pages to flip through is unpredictable when you have a large number of potential columns. What if you want to include all columns on the same page? You can take advantage of the repeating behavior of a tablix and get repeating columns by embedding one tablix inside of another. For this example, I'm using SQL Server 2008 R2 Reporting Services. You can get similar results with SQL Server 2008. (In fact, you could probably do something similar in SQL Server 2005, but I haven't tested it. The steps would be slightly different because you would be working with the old-style matrix as compared to the new-style tablix discussed in this post.) I created a dataset that queries AdventureWorksDW2008 tables: SELECT TOP (100) e.LastName + ', ' + e.FirstName AS EmployeeName, d.FullDateAlternateKey, f.SalesOrderNumber, p.EnglishProductName, sum(SalesAmount) as SalesAmount FROM FactResellerSales AS f INNER JOIN DimProduct AS p ON p.ProductKey = f.ProductKey INNER JOIN DimDate AS d ON d.DateKey = f.OrderDateKey INNER JOIN DimEmployee AS e ON e.EmployeeKey = f.EmployeeKey GROUP BY p.EnglishProductName, d.FullDateAlternateKey, e.LastName + ', ' + e.FirstName, f.SalesOrderNumber ORDER BY EmployeeName, f.SalesOrderNumber, p.EnglishProductName To start the report: Add a matrix to the report body and drag Employee Name to the row header, which also creates a group. Next drag SalesOrderNumber below Employee Name in the Row Groups panel, which creates a second group and a second column in the row header section of the matrix, as shown in Figure 4. Now for some trickiness. Add another column to the row headers. This new column will be associated with the existing EmployeeName group rather than causing BIDS to create a new group. To do this, right-click on the EmployeeName textbox in the bottom row, point to Insert Column, and then click Inside Group-Right. Then add the SalesOrderNumber field to this new column. By doing this, you're creating a report that repeats a set of columns for each EmployeeName/SalesOrderNumber combination that appears in the data. Next, modify the first row group's expression to group on both EmployeeName and SalesOrderNumber. In the Row Groups section, right-click EmployeeName, click Group Properties, click the Add button, and select [SalesOrderNumber]. Now you need to configure the columns to repeat. Rather than use the Columns group of the matrix like you might expect, you're going to use the textbox that belongs to the second group of the tablix as a location for embedding other report items. First, clear out the text that's currently in the third column - SalesOrderNumber - because it's already added as a separate textbox in this report design. Then drag and drop a matrix into that textbox, as shown in Figure 5. Again, you need to do some tricks here to get the appearance and behavior right. We don't really want repeating rows in the embedded matrix, so follow these steps: Click on the Rows label which then displays RowGroup in the Row Groups pane below the report body. Right-click on RowGroup,click Delete Group, and select the option to delete associated rows and columns. As a result, you get a modified matrix which has only a ColumnGroup in it, with a row above a double-dashed line for the column group and a row below the line for the aggregated data. Let's continue: Drag EnglishProductName to the data textbox (below the line). Add a second data row by right-clicking EnglishProductName, pointing to Insert Row, and clicking Below. Add the SalesAmount field to the new data textbox. Now eliminate the column group row without eliminating the group. To do this, right-click the row above the double-dashed line, click Delete Rows, and then select Delete Rows Only in the message box. Now you're ready for the fit and finish phase: Resize the column containing the embedded matrix so that it fits completely. Also, the final column in the matrix is for the column group. You can't delete this column, but you can make it as small as possible. Just click on the matrix to display the row and column handles, and then drag the right edge of the rightmost column to the left to make the column virtually disappear. Next, configure the groups so that the columns of the embedded matrix will wrap. In the Column Groups pane, right-click ColumnGroup1 and click on the expression button (labeled fx) to the right of Group On [EnglishProductName]. Replace the expression with the following: =RowNumber("SalesOrderNumber" ). We use SalesOrderNumber here because that is the name of the group that "contains" the embedded matrix. The next step is to configure the number of columns to display before wrapping. Click any cell in the matrix that is not inside the embedded matrix, and then double-click the second group in the Row Groups pane - SalesOrderNumber. Change the group expression to the following expression: =Ceiling(RowNumber("EmployeeName")/3) The last step is to apply formatting. In my example, I set the SalesAmount textbox's Format property to C2 and also right-aligned the text in both the EnglishProductName and the SalesAmount textboxes. And voila - Figure 6 shows a matrix report with wrapping columns. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • .NET 4.5 is an in-place replacement for .NET 4.0

    - by Rick Strahl
    With the betas for .NET 4.5 and Visual Studio 11 and Windows 8 shipping many people will be installing .NET 4.5 and hacking away on it. There are a number of great enhancements that are fairly transparent, but it's important to understand what .NET 4.5 actually is in terms of the CLR running on your machine. When .NET 4.5 is installed it effectively replaces .NET 4.0 on the machine. .NET 4.0 gets overwritten by a new version of .NET 4.5 which - according to Microsoft - is supposed to be 100% backwards compatible. While 100% backwards compatible sounds great, we all know that 100% is a hard number to hit, and even the aforementioned blog post at the Microsoft site acknowledges this. But there's so much more than backwards compatibility that makes this awkward at best and confusing at worst. What does ‘Replacement’ mean? When you install .NET 4.5 your .NET 4.0 assemblies in the \Windows\.NET Framework\V4.0.30319 are overwritten with a new set of assemblies. You end up with overwritten assemblies as well as a bunch of new ones (like the new System.Net.Http assemblies for example). The following screen shot demonstrates system.dll on my test machine (left) running .NET 4.5 on the right and my production laptop running stock .NET 4.0 (right):   Clearly they are different files with a difference in file sizes (interesting that the 4.5 version is actually smaller). That’s not all. If you actually query the runtime version when .NET 4.5 is installed with with Environment.Version you still get: 4.0.30319 If you open the properties of System.dll assembly in .NET 4.5 you'll also see: Notice that the file version is also left at 4.0.xxx. There are differences in build numbers: .NET 4.0 shows 261 and the current .NET 4.5 beta build is 17379. I suppose you can use assume a build number greater than 17000 is .NET 4.5, but that's pretty hokey to say the least. There’s no easy or obvious way to tell whether you are running on 4.0 or 4.5 – to the application they appear to be the same runtime version. And that is what Microsoft intends here. .NET 4.5 is intended as an in-place upgrade. Compile to 4.5 run on 4.0 – not quite! You can compile an application for .NET 4.5 and run it on the 4.0 runtime – that is until you hit a new feature that doesn’t exist on 4.0. At which point the app bombs at runtime. Say you write some code that is mostly .NET 4.0, but only has a few of the new features of .NET 4.5 like aync/await buried deep in the bowels of the application where it only fires occasionally. .NET will happily start your application and run everything 4.0 fine, until it hits that 4.5 code – and then crash unceremoniously at runtime. Oh joy! You can .NET 4.0 applications on .NET 4.5 of course and that should work without much fanfare. Different than .NET 3.0/3.5 Note that this in-place replacement is very different from the side by side installs of .NET 2.0 and 3.0/3.5 which all ran on the 2.0 version of the CLR. The two 3.x versions were basically library enhancements on top of the core .NET 2.0 runtime. Both versions ran under the .NET 2.0 runtime which wasn’t changed (other than for security patches and bug fixes) for the whole 3.x cycle. The 4.5 update instead completely replaces the .NET 4.0 runtime and leaves the actual version number set at v4.0.30319. When you build a new project with Visual Studio 2011, you can still target .NET 4.0 or you can target .NET 4.5. But you are in effect referencing the same set of assemblies for both regardless which version you use. What's different is the compiler used to compile and link your code so compiling with .NET 4.0 gives you just the subset of the functionality that is available in .NET 4.0, but when you use the 4.5 compiler you get the full functionality of what’s actually available in the assemblies and extra libraries. It doesn’t look like you will be able to use Visual Studio 2010 to develop .NET 4.5 applications. Good news – Bad news Microsoft is trying hard to experiment with every possible permutation of releasing new versions of the .NET framework apparently. No two updates have been the same. Clearly updating to a full new version of .NET (ie. .NET 2.0, 4.0 and at some point 5.0 runtimes) has its own set of challenges, but doing an in-place update of the runtime and then not even providing a good way to tell which version is installed is pretty whacky even by Microsoft’s standards. Especially given that .NET 4.5 includes a fairly significant update with all the aysnc functionality baked into the runtime. Most of the IO APIs have been updated to support task based async operation which significantly affects many existing APIs. To make things worse .NET 4.5 will be the initial version of .NET that ships with Windows 8 so it will be with us for a long time to come unless Microsoft finally decides to push .NET versions onto Windows machines as part of system upgrades (which currently doesn’t happen). This is the same story we had when Vista launched with .NET 3.0 which was a minor version that quickly was replaced by 3.5 which was more long lived and practical. People had enough problems dealing with the confusing versioning of the 3.x versions which ran on .NET 2.0. I can’t count the amount support calls and questions I’ve fielded because people couldn’t find a .NET 3.5 entry in the IIS version dialog. The same is likely to happen with .NET 4.5. It’s all well and good when we know that .NET 4.5 is an in-place replacement, but administrators and IT folks not intimately familiar with .NET are unlikely to understand this nuance and end up thoroughly confused which version is installed. It’s hard for me to see any upside to an in-place update and I haven’t really seen a good explanation of why this approach was decided on. Sure if the version stays the same existing assembly bindings don’t break so applications can stay running through an update. I suppose this is useful for some component vendors and strongly signed assemblies in corporate environments. But seriously, if you are going to throw .NET 4.5 into the mix, who won’t be recompiling all code and thoroughly test that code to work on .NET 4.5? A recompile requirement doesn’t seem that serious in light of a major version upgrade.  Resources http://blogs.msdn.com/b/dotnet/archive/2011/09/26/compatibility-of-net-framework-4-5.aspx http://www.devproconnections.com/article/net-framework/net-framework-45-versioning-faces-problems-141160© Rick Strahl, West Wind Technologies, 2005-2012Posted in .NET   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Binding collection indexes to a WPF DataGrid at runtime

    - by bearda
    After trying to develop our own control to display a table of data we stumbled on the WPF toolkit DataGrid and thought we were saved. A couple hours later I'm scratching my head trying to figure out if it can do what we really want it to do. The DataGrid seems to be based on displaying various properties of a single object, where I think I need something that can display a collection's items, I want to display a table of strings with a variable number of rows and a variable number of columns. Each row represents the state of a number of inputs at a given time. The number of samples may change, and the number of inputs may change at runtime. As a result, I can't create a custom object that represents a row with a property for each input. This makes the DataGrid binding more complicated, since I can't bind to a fixed property for each column. I thought I found a workaround for this by binding to ".[" + channelIndex + ]" but it hasn't worked out quite the way I wanted. Right now I have a collection of a collection of strings that represents the two-dimensional array of strings. I'm using ObservableCollection so string change event notifications work, but I can use any collection type needed. It looked like everything was working great until I realized that every row was showing the same line of data. Binding in C# is not my strong suit, so I'm kind of lost on what's going wrong. Is what I'm trying to do overall even possible with the WPF Toolkit DataGrid? using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; using Microsoft.Windows.Controls; using System.ComponentModel; using System.Collections; using System.Collections.ObjectModel; namespace WRE.NGDAS.UILayer { /// <summary> /// Interaction logic for DataTableControl.xaml /// </summary> public partial class DataTableControl : UserControl { #region Constants private const int lineHeight = 25; #endregion #region Type Definitions private class TableChannelInfo { internal string ChannelName = string.Empty; internal int Column = 0; public override string ToString() { return ChannelName; } } internal class NotifyString : INotifyPropertyChanged { private string text = String.Empty; public event PropertyChangedEventHandler PropertyChanged; public string Text { get { return text; } set { text = value; NotifyPropertyChanged( "Text" ); } } public NotifyString(string newText) { text = newText; } protected void NotifyPropertyChanged( string propertyChanged ) { if ( PropertyChanged != null ) { PropertyChanged(this, new PropertyChangedEventArgs(propertyChanged)); } } } #endregion #region Private Data Members string[] channels = null; int numberFixed = 0; int numberOfRows = 0; ObservableCollection<ObservableCollection<NotifyString>> tableText = null; #endregion public DataTableControl( List<string> channelNames, List<string> nameToolTips, int numberFixedColumns, int numberRows ) { InitializeComponent(); numberFixed = numberFixedColumns; numberOfRows = numberRows; tableText = new ObservableCollection<ObservableCollection<NotifyString>>(); dataGrid.ItemsSource = tableText; channels = new string[channelNames.Count]; for (int channelIndex = 0; channelIndex < channelNames.Count; channelIndex++) { channels[channelIndex] = channelNames[channelIndex]; tableText.Add(new ObservableCollection<NotifyString>()); for (int i = 0; i < numberOfRows; i++) { tableText[channelIndex].Add( new NotifyString(String.Empty) ); } Binding textBinding = new Binding( ".[" + channelIndex + "]" ); textBinding.Mode = BindingMode.OneWay; textBinding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged; textBinding.Source = tableText[channelIndex]; DataGridTextColumn newColumn = new DataGridTextColumn(); newColumn.Header = channelNames[channelIndex]; newColumn.DisplayIndex = channelIndex; newColumn.Binding = textBinding; if ( channelIndex < numberFixed ) { newColumn.CanUserReorder = false; } dataGrid.Columns.Add(newColumn); } //Height = lineHeight + numberOfRows * lineHeight; } internal void UpdateChannelRow( int rowNumber, List<string> channelValues, DisplayColors color ) { if ( rowNumber < numberOfRows ) { for (int column = 0; column < channelValues.Count; column++) { if ( column < channels.GetLength(0) ) { tableText[column][rowNumber].Text = channelValues[column]; } } } } } }

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  • MySQL – Scalability on Amazon RDS: Scale out to multiple RDS instances

    - by Pinal Dave
    Today, I’d like to discuss getting better MySQL scalability on Amazon RDS. The question of the day: “What can you do when a MySQL database needs to scale write-intensive workloads beyond the capabilities of the largest available machine on Amazon RDS?” Let’s take a look. In a typical EC2/RDS set-up, users connect to app servers from their mobile devices and tablets, computers, browsers, etc.  Then app servers connect to an RDS instance (web/cloud services) and in some cases they might leverage some read-only replicas.   Figure 1. A typical RDS instance is a single-instance database, with read replicas.  This is not very good at handling high write-based throughput. As your application becomes more popular you can expect an increasing number of users, more transactions, and more accumulated data.  User interactions can become more challenging as the application adds more sophisticated capabilities. The result of all this positive activity: your MySQL database will inevitably begin to experience scalability pressures. What can you do? Broadly speaking, there are four options available to improve MySQL scalability on RDS. 1. Larger RDS Instances – If you’re not already using the maximum available RDS instance, you can always scale up – to larger hardware.  Bigger CPUs, more compute power, more memory et cetera. But the largest available RDS instance is still limited.  And they get expensive. “High-Memory Quadruple Extra Large DB Instance”: 68 GB of memory 26 ECUs (8 virtual cores with 3.25 ECUs each) 64-bit platform High I/O Capacity Provisioned IOPS Optimized: 1000Mbps 2. Provisioned IOPs – You can get provisioned IOPs and higher throughput on the I/O level. However, there is a hard limit with a maximum instance size and maximum number of provisioned IOPs you can buy from Amazon and you simply cannot scale beyond these hardware specifications. 3. Leverage Read Replicas – If your application permits, you can leverage read replicas to offload some reads from the master databases. But there are a limited number of replicas you can utilize and Amazon generally requires some modifications to your existing application. And read-replicas don’t help with write-intensive applications. 4. Multiple Database Instances – Amazon offers a fourth option: “You can implement partitioning,thereby spreading your data across multiple database Instances” (Link) However, Amazon does not offer any guidance or facilities to help you with this. “Multiple database instances” is not an RDS feature.  And Amazon doesn’t explain how to implement this idea. In fact, when asked, this is the response on an Amazon forum: Q: Is there any documents that describe the partition DB across multiple RDS? I need to use DB with more 1TB but exist a limitation during the create process, but I read in the any FAQ that you need to partition database, but I don’t find any documents that describe it. A: “DB partitioning/sharding is not an official feature of Amazon RDS or MySQL, but a technique to scale out database by using multiple database instances. The appropriate way to split data depends on the characteristics of the application or data set. Therefore, there is no concrete and specific guidance.” So now what? The answer is to scale out with ScaleBase. Amazon RDS with ScaleBase: What you get – MySQL Scalability! ScaleBase is specifically designed to scale out a single MySQL RDS instance into multiple MySQL instances. Critically, this is accomplished with no changes to your application code.  Your application continues to “see” one database.   ScaleBase does all the work of managing and enforcing an optimized data distribution policy to create multiple MySQL instances. With ScaleBase, data distribution, transactions, concurrency control, and two-phase commit are all 100% transparent and 100% ACID-compliant, so applications, services and tooling continue to interact with your distributed RDS as if it were a single MySQL instance. The result: now you can cost-effectively leverage multiple MySQL RDS instance to scale out write-intensive workloads to an unlimited number of users, transactions, and data. Amazon RDS with ScaleBase: What you keep – Everything! And how does this change your Amazon environment? 1. Keep your application, unchanged – There is no change your application development life-cycle at all.  You still use your existing development tools, frameworks and libraries.  Application quality assurance and testing cycles stay the same. And, critically, you stay with an ACID-compliant MySQL environment. 2. Keep your RDS value-added services – The value-added services that you rely on are all still available. Amazon will continue to handle database maintenance and updates for you. You can still leverage High Availability via Multi A-Z.  And, if it benefits youra application throughput, you can still use read replicas. 3. Keep your RDS administration – Finally the RDS monitoring and provisioning tools you rely on still work as they did before. With your one large MySQL instance, now split into multiple instances, you can actually use less expensive, smallersmaller available RDS hardware and continue to see better database performance. Conclusion Amazon RDS is a tremendous service, but it doesn’t offer solutions to scale beyond a single MySQL instance. Larger RDS instances get more expensive.  And when you max-out on the available hardware, you’re stuck.  Amazon recommends scaling out your single instance into multiple instances for transaction-intensive apps, but offers no services or guidance to help you. This is where ScaleBase comes in to save the day. It gives you a simple and effective way to create multiple MySQL RDS instances, while removing all the complexities typically caused by “DIY” sharding andwith no changes to your applications . With ScaleBase you continue to leverage the AWS/RDS ecosystem: commodity hardware and value added services like read replicas, multi A-Z, maintenance/updates and administration with monitoring tools and provisioning. SCALEBASE ON AMAZON If you’re curious to try ScaleBase on Amazon, it can be found here – Download NOW. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: MySQL, PostADay, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • DELETE and EDIT is not working in my python program

    - by user2968025
    This is a simple python program that ADD, DELETE, EDIT and VIEW student records. The problem is, DELETE and EDIT is not working. I dont know why but when I tried removing one '?' in the DELETE dunction, I had the error that says there are only 8 columns and it needs 10. But originally, there are only 9 columns. I don't know where it got the other one to make it 10. Please help.. :( import sys import sqlite3 import tkinter import tkinter as tk from tkinter import * from tkinter.ttk import * def newRecord(): studentnum="" name="" age="" birthday="" address="" email="" course="" year="" section="" con=sqlite3.connect("Students.db") cur=con.cursor() cur.execute("CREATE TABLE IF NOT EXISTS student(studentnum TEXT, name TEXT, age TEXT, birthday TEXT, address TEXT, email TEXT, course TEXT, year TEXT, section TEXT)") def save(): studentnum=en1.get() name=en2.get() age=en3.get() birthday=en4.get() address=en5.get() email=en6.get() course=en7.get() year=en8.get() section=en9.get() student=(studentnum,name,age,birthday,address,email,course,year,section) cur.execute("INSERT INTO student(studentnum,name,age,birthday,address,email,course,year,section) VALUES(?,?,?,?,?,?,?,?,?)",student) con.commit() win=tkinter.Tk();win.title("Students") lbl=tkinter.Label(win,background="#000",foreground="#ddd",width=30,text="Add Record") lbl.pack() lbl1=tkinter.Label(win,width=30,text="Student Number : ") lbl1.pack() en1=tkinter.Entry(win,width=30) en1.pack() lbl2=tkinter.Label(win,width=30,text="Name : ") lbl2.pack() en2=tkinter.Entry(win,width=30) en2.pack() lbl3=tkinter.Label(win,width=30,text="Age : ") lbl3.pack() en3=tkinter.Entry(win,width=30) en3.pack() lbl4=tkinter.Label(win,width=30,text="Birthday : ") lbl4.pack() en4=tkinter.Entry(win,width=30) en4.pack() lbl5=tkinter.Label(win,width=30,text="Address : ") lbl5.pack() en5=tkinter.Entry(win,width=30) en5.pack() lbl6=tkinter.Label(win,width=30,text="Email : ") lbl6.pack() en6=tkinter.Entry(win,width=30) en6.pack() lbl7=tkinter.Label(win,width=30,text="Course : ") lbl7.pack() en7=tkinter.Entry(win,width=30) en7.pack() lbl8=tkinter.Label(win,width=30,text="Year : ") lbl8.pack() en8=tkinter.Entry(win,width=30) en8.pack() lbl9=tkinter.Label(win,width=30,text="Section : ") lbl9.pack() en9=tkinter.Entry(win,width=30) en9.pack() btn1=tkinter.Button(win,background="#000",foreground="#ddd",width=30,text="Save Student",command=save) btn1.pack() def editRecord(): studentnum1="" def edit(): studentnum1=en10.get() studentnum="" name="" age="" birthday="" address="" email="" course="" year="" section="" con=sqlite3.connect("Students.db") cur=con.cursor() row=cur.fetchone() cur.execute("DELETE FROM student WHERE name = '%s'" % studentnum1) con.commit() def save(): studentnum=en1.get() name=en2.get() age=en3.get() birthday=en4.get() address=en5.get() email=en6.get() course=en7.get() year=en8.get() section=en8.get() student=(studentnum,name,age,email,birthday,address,email,course,year,section) cur.execute("INSERT INTO student(studentnum,name,age,email,birthday,address,email,course,year,section) VALUES(?,?,?,?,?,?,?,?,?)",student) con.commit() win=tkinter.Tk();win.title("Students") lbl=tkinter.Label(win,background="#000",foreground="#ddd",width=30,text="Edit Reocrd :"+'\t'+studentnum1) lbl.pack() lbl1=tkinter.Label(win,width=30,text="Student Number : ") lbl1.pack() en1=tkinter.Entry(win,width=30) en1.pack() lbl2=tkinter.Label(win,width=30,text="Name : ") lbl2.pack() en2=tkinter.Entry(win,width=30) en2.pack() lbl3=tkinter.Label(win,width=30,text="Age : ") lbl3.pack() en3=tkinter.Entry(win,width=30) en3.pack() lbl4=tkinter.Label(win,width=30,text="Birthday : ") lbl4.pack() en4=tkinter.Entry(win,width=30) en4.pack() lbl5=tkinter.Label(win,width=30,text="Address : ") lbl5.pack() en5=tkinter.Entry(win,width=30) en5.pack() lbl6=tkinter.Label(win,width=30,text="Email : ") lbl6.pack() en6=tkinter.Entry(win,width=30) en6.pack() lbl7=tkinter.Label(win,width=30,text="Course : ") lbl7.pack() en7=tkinter.Entry(win,width=30) en7.pack() lbl8=tkinter.Label(win,width=30,text="Year : ") lbl8.pack() en8=tkinter.Entry(win,width=30) en8.pack() lbl9=tkinter.Label(win,width=30,text="Section : ") lbl9.pack() en9=tkinter.Entry(win,width=30) en9.pack() btn1=tkinter.Button(win,background="#000",foreground="#ddd",width=30,text="Save Record",command=save) btn1.pack() win=tkinter.Tk();win.title("Edit Student") lbl=tkinter.Label(win,background="#000",foreground="#ddd",width=30,text="Edit Record") lbl.pack() lbl10=tkinter.Label(win,width=30,text="Student Number : ") lbl10.pack() en10=tkinter.Entry(win) en10.pack() btn2=tkinter.Button(win,background="#000",foreground="#ddd",width=30,text="Edit",command=edit) btn2.pack() def deleteRecord(): studentnum1="" win=tkinter.Tk();win.title("Delete Student Record") lbl=tkinter.Label(win,background="#000",foreground="#ddd",width=30,text="Delete Record") lbl.pack() lbl10=tkinter.Label(win,text="Student Number") lbl10.pack() en10=tkinter.Entry(win) en10.pack() def delete(): studentnum1=en10.get() con=sqlite3.connect("Students.db") cur=con.cursor() row=cur.fetchone() cur.execute("DELETE FROM student WHERE name = '%s';" % studentnum1) con.commit() win=tkinter.Tk();win.title("Record Deleted") lbl=tkinter.Label(win,background="#000",foreground="#ddd",width=30,text="Record Deleted :") lbl.pack() lbl=tkinter.Label(win,width=30,text=studentnum1) lbl.pack() btn=tkinter.Button(win,background="#000",foreground="#ddd",width=30,text="Ok",command=win.destroy) btn.pack() btn2=tkinter.Button(win,background="#000",foreground="#ddd",width=30,text="Delete",command=delete) btn2.pack() def viewRecord(): con=sqlite3.connect("Students.db") cur=con.cursor() win=tkinter.Tk();win.title("View Student Record"); row=cur.fetchall() lbl1=tkinter.Label(win,background="#000",foreground="#ddd",width=300,text="\n\tStudent Number"+"\t\tName"+"\t\tAge"+"\t\tBirthday"+"\t\tAddress"+"\t\tEmail"+"\t\tCourse"+"\t\tYear"+"\t\nSection") lbl1.pack() for row in cur.execute("SELECT * FROM student"): lbl2=tkinter.Label(win,width=300,text= row[0] + '\t\t' + row[1] + '\t' + row[2] + '\t\t' + row[3] + '\t\t' + row[4] + '\t\t' + row[5] + '\t\t' + row[6] + '\t\t' + row[7] + '\t\t' + row[8] + '\n') lbl2.pack() con.close() but1=tkinter.Button(win,background="#000",foreground="#fff", width=150,text="Close",command=win.destroy) but1.pack() root=tkinter.Tk();root.title("Student Records") menubar=tkinter.Menu(root) manage=tkinter.Menu(menubar,tearoff=0) manage.add_command(label='New Record',command=newRecord) manage.add_command(label='Edit Record',command=editRecord) manage.add_command(label='Delete Record',command=deleteRecord) menubar.add_cascade(label='Manage',menu=manage) view=tkinter.Menu(menubar,tearoff=0) view.add_command(label='View Record',command=viewRecord) menubar.add_cascade(label='View',menu=view) root.config(menu=menubar) lbl=tkinter.Label(root,background="#000",foreground="#ddd",font=("Verdana",15),width=30,text="Student Records") lbl.pack() lbl1=tkinter.Label(root,text="\nSubmitted by :") lbl1.pack() lbl2=tkinter.Label(root,text="Chavez, Vissia Nicole P") lbl2.pack() lbl3=tkinter.Label(root,text="BSIT 4-4") lbl3.pack()

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  • Why does Akonadi on KDE 4.6.0 refuse to start?

    - by Patches
    Akonadi refuses to start on my fresh installation of KDE 4.6.0 from the kubuntu-backports PPA on Ubuntu 10.10 Maverick Meerkat, preventing me from usking KMail. Here is the full error output: patches@pleistocene:~/.local/share$ akonadictl start Starting Akonadi Server... done. patches@pleistocene:~/.local/share$ Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString) search paths: ("/home/patches/bin", "/usr/local/sbin", "/usr/local/bin", "/usr/sbin", "/usr/bin", "/sbin", "/bin", "/usr/games", "/usr/sbin", "/usr/local/sbin", "/usr/local/libexec", "/usr/libexec", "/opt/mysql/libexec", "/opt/local/lib/mysql5/bin", "/opt/mysql/sbin") Found mysql_install_db: "/usr/bin/mysql_install_db" Found mysqlcheck: "/usr/bin/mysqlcheck" Database process exited unexpectedly during initial connection! executable: "/usr/sbin/mysqld-akonadi" arguments: ("--defaults-file=/home/patches/.local/share/akonadi//mysql.conf", "--datadir=/home/patches/.local/share/akonadi/db_data/", "--socket=/home/patches/.local/share/akonadi/socket-pleistocene/mysql.socket") stdout: "" stderr: "Could not open required defaults file: /home/patches/.local/share/akonadi//mysql.conf Fatal error in defaults handling. Program aborted 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Note] Plugin 'FEDERATED' is disabled. /usr/sbin/mysqld-akonadi: Can't find file: './mysql/plugin.frm' (errno: 13) 110209 16:41:12 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 110209 16:41:12 InnoDB: Operating system error number 13 in a file operation. InnoDB: The error means mysqld does not have the access rights to InnoDB: the directory. InnoDB: File name ./ibdata1 InnoDB: File operation call: 'create'. InnoDB: Cannot continue operation. " exit code: 1 process error: "Unknown error" "[ 0: akonadiserver(_Z11akBacktracev+0x35) [0x8086055] 1: akonadiserver() [0x8086516] 2: [0xb772e400] 3: [0xb772e416] 4: /lib/libc.so.6(gsignal+0x51) [0xb6e9f941] 5: /lib/libc.so.6(abort+0x182) [0xb6ea2e42] 6: /usr/lib/libQtCore.so.4(_Z17qt_message_output9QtMsgTypePKc+0x8c) [0xb74d62dc] 7: akonadiserver(_ZN15FileDebugStream9writeDataEPKcx+0xc4) [0x8087574] 8: /usr/lib/libQtCore.so.4(_ZN9QIODevice5writeEPKcx+0x8e) [0xb757168e] 9: /usr/lib/libQtCore.so.4(+0x103425) [0xb7581425] 10: /usr/lib/libQtCore.so.4(_ZN11QTextStreamD1Ev+0x3d) [0xb758295d] 11: akonadiserver(_ZN6QDebugD1Ev+0x43) [0x8081b73] 12: akonadiserver(_ZN13DbConfigMysql19startInternalServerEv+0x1c27) [0x810c177] 13: akonadiserver(_ZN7Akonadi13AkonadiServer20startDatabaseProcessEv+0xe3) [0x8087a23] 14: akonadiserver(_ZN7Akonadi13AkonadiServerC1EP7QObject+0xca) [0x8088b6a] 15: akonadiserver(_ZN7Akonadi13AkonadiServer8instanceEv+0x48) [0x808a1d8] 16: akonadiserver(main+0x364) [0x8080fb4] 17: /lib/libc.so.6(__libc_start_main+0xe7) [0xb6e8bce7] 18: akonadiserver() [0x8080b81] ] " ProcessControl: Application 'akonadiserver' returned with exit code 255 (Unknown error) search paths: ("/home/patches/bin", "/usr/local/sbin", "/usr/local/bin", "/usr/sbin", "/usr/bin", "/sbin", "/bin", "/usr/games", "/usr/sbin", "/usr/local/sbin", "/usr/local/libexec", "/usr/libexec", "/opt/mysql/libexec", "/opt/local/lib/mysql5/bin", "/opt/mysql/sbin") Found mysql_install_db: "/usr/bin/mysql_install_db" Found mysqlcheck: "/usr/bin/mysqlcheck" Database process exited unexpectedly during initial connection! executable: "/usr/sbin/mysqld-akonadi" arguments: ("--defaults-file=/home/patches/.local/share/akonadi//mysql.conf", "--datadir=/home/patches/.local/share/akonadi/db_data/", "--socket=/home/patches/.local/share/akonadi/socket-pleistocene/mysql.socket") stdout: "" stderr: "Could not open required defaults file: /home/patches/.local/share/akonadi//mysql.conf Fatal error in defaults handling. Program aborted 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Note] Plugin 'FEDERATED' is disabled. /usr/sbin/mysqld-akonadi: Can't find file: './mysql/plugin.frm' (errno: 13) 110209 16:41:12 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 110209 16:41:12 InnoDB: Operating system error number 13 in a file operation. InnoDB: The error means mysqld does not have the access rights to InnoDB: the directory. InnoDB: File name ./ibdata1 InnoDB: File operation call: 'create'. InnoDB: Cannot continue operation. " exit code: 1 process error: "Unknown error" "[ 0: akonadiserver(_Z11akBacktracev+0x35) [0x8086055] 1: akonadiserver() [0x8086516] 2: [0xb77ae400] 3: [0xb77ae416] 4: /lib/libc.so.6(gsignal+0x51) [0xb6f1f941] 5: /lib/libc.so.6(abort+0x182) [0xb6f22e42] 6: /usr/lib/libQtCore.so.4(_Z17qt_message_output9QtMsgTypePKc+0x8c) [0xb75562dc] 7: akonadiserver(_ZN15FileDebugStream9writeDataEPKcx+0xc4) [0x8087574] 8: /usr/lib/libQtCore.so.4(_ZN9QIODevice5writeEPKcx+0x8e) [0xb75f168e] 9: /usr/lib/libQtCore.so.4(+0x103425) [0xb7601425] 10: /usr/lib/libQtCore.so.4(_ZN11QTextStreamD1Ev+0x3d) [0xb760295d] 11: akonadiserver(_ZN6QDebugD1Ev+0x43) [0x8081b73] 12: akonadiserver(_ZN13DbConfigMysql19startInternalServerEv+0x1c27) [0x810c177] 13: akonadiserver(_ZN7Akonadi13AkonadiServer20startDatabaseProcessEv+0xe3) [0x8087a23] 14: akonadiserver(_ZN7Akonadi13AkonadiServerC1EP7QObject+0xca) [0x8088b6a] 15: akonadiserver(_ZN7Akonadi13AkonadiServer8instanceEv+0x48) [0x808a1d8] 16: akonadiserver(main+0x364) [0x8080fb4] 17: /lib/libc.so.6(__libc_start_main+0xe7) [0xb6f0bce7] 18: akonadiserver() [0x8080b81] ] " ProcessControl: Application 'akonadiserver' returned with exit code 255 (Unknown error) search paths: ("/home/patches/bin", "/usr/local/sbin", "/usr/local/bin", "/usr/sbin", "/usr/bin", "/sbin", "/bin", "/usr/games", "/usr/sbin", "/usr/local/sbin", "/usr/local/libexec", "/usr/libexec", "/opt/mysql/libexec", "/opt/local/lib/mysql5/bin", "/opt/mysql/sbin") Found mysql_install_db: "/usr/bin/mysql_install_db" Found mysqlcheck: "/usr/bin/mysqlcheck" Database process exited unexpectedly during initial connection! executable: "/usr/sbin/mysqld-akonadi" arguments: ("--defaults-file=/home/patches/.local/share/akonadi//mysql.conf", "--datadir=/home/patches/.local/share/akonadi/db_data/", "--socket=/home/patches/.local/share/akonadi/socket-pleistocene/mysql.socket") stdout: "" stderr: "Could not open required defaults file: /home/patches/.local/share/akonadi//mysql.conf Fatal error in defaults handling. Program aborted 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Note] Plugin 'FEDERATED' is disabled. /usr/sbin/mysqld-akonadi: Can't find file: './mysql/plugin.frm' (errno: 13) 110209 16:41:12 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 110209 16:41:12 InnoDB: Operating system error number 13 in a file operation. InnoDB: The error means mysqld does not have the access rights to InnoDB: the directory. InnoDB: File name ./ibdata1 InnoDB: File operation call: 'create'. InnoDB: Cannot continue operation. " exit code: 1 process error: "Unknown error" "[ 0: akonadiserver(_Z11akBacktracev+0x35) [0x8086055] 1: akonadiserver() [0x8086516] 2: [0xb778b400] 3: [0xb778b416] 4: /lib/libc.so.6(gsignal+0x51) [0xb6efc941] 5: /lib/libc.so.6(abort+0x182) [0xb6effe42] 6: /usr/lib/libQtCore.so.4(_Z17qt_message_output9QtMsgTypePKc+0x8c) [0xb75332dc] 7: akonadiserver(_ZN15FileDebugStream9writeDataEPKcx+0xc4) [0x8087574] 8: /usr/lib/libQtCore.so.4(_ZN9QIODevice5writeEPKcx+0x8e) [0xb75ce68e] 9: /usr/lib/libQtCore.so.4(+0x103425) [0xb75de425] 10: /usr/lib/libQtCore.so.4(_ZN11QTextStreamD1Ev+0x3d) [0xb75df95d] 11: akonadiserver(_ZN6QDebugD1Ev+0x43) [0x8081b73] 12: akonadiserver(_ZN13DbConfigMysql19startInternalServerEv+0x1c27) [0x810c177] 13: akonadiserver(_ZN7Akonadi13AkonadiServer20startDatabaseProcessEv+0xe3) [0x8087a23] 14: akonadiserver(_ZN7Akonadi13AkonadiServerC1EP7QObject+0xca) [0x8088b6a] 15: akonadiserver(_ZN7Akonadi13AkonadiServer8instanceEv+0x48) [0x808a1d8] 16: akonadiserver(main+0x364) [0x8080fb4] 17: /lib/libc.so.6(__libc_start_main+0xe7) [0xb6ee8ce7] 18: akonadiserver() [0x8080b81] ] " ProcessControl: Application 'akonadiserver' returned with exit code 255 (Unknown error) search paths: ("/home/patches/bin", "/usr/local/sbin", "/usr/local/bin", "/usr/sbin", "/usr/bin", "/sbin", "/bin", "/usr/games", "/usr/sbin", "/usr/local/sbin", "/usr/local/libexec", "/usr/libexec", "/opt/mysql/libexec", "/opt/local/lib/mysql5/bin", "/opt/mysql/sbin") Found mysql_install_db: "/usr/bin/mysql_install_db" Found mysqlcheck: "/usr/bin/mysqlcheck" Database process exited unexpectedly during initial connection! executable: "/usr/sbin/mysqld-akonadi" arguments: ("--defaults-file=/home/patches/.local/share/akonadi//mysql.conf", "--datadir=/home/patches/.local/share/akonadi/db_data/", "--socket=/home/patches/.local/share/akonadi/socket-pleistocene/mysql.socket") stdout: "" stderr: "Could not open required defaults file: /home/patches/.local/share/akonadi//mysql.conf Fatal error in defaults handling. Program aborted 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Warning] Can't create test file /home/patches/.local/share/akonadi/db_data/pleistocene.lower-test 110209 16:41:12 [Note] Plugin 'FEDERATED' is disabled. /usr/sbin/mysqld-akonadi: Can't find file: './mysql/plugin.frm' (errno: 13) 110209 16:41:12 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 110209 16:41:12 InnoDB: Operating system error number 13 in a file operation. InnoDB: The error means mysqld does not have the access rights to InnoDB: the directory. InnoDB: File name ./ibdata1 InnoDB: File operation call: 'create'. InnoDB: Cannot continue operation. " exit code: 1 process error: "Unknown error" "[ 0: akonadiserver(_Z11akBacktracev+0x35) [0x8086055] 1: akonadiserver() [0x8086516] 2: [0xb784e400] 3: [0xb784e416] 4: /lib/libc.so.6(gsignal+0x51) [0xb6fbf941] 5: /lib/libc.so.6(abort+0x182) [0xb6fc2e42] 6: /usr/lib/libQtCore.so.4(_Z17qt_message_output9QtMsgTypePKc+0x8c) [0xb75f62dc] 7: akonadiserver(_ZN15FileDebugStream9writeDataEPKcx+0xc4) [0x8087574] 8: /usr/lib/libQtCore.so.4(_ZN9QIODevice5writeEPKcx+0x8e) [0xb769168e] 9: /usr/lib/libQtCore.so.4(+0x103425) [0xb76a1425] 10: /usr/lib/libQtCore.so.4(_ZN11QTextStreamD1Ev+0x3d) [0xb76a295d] 11: akonadiserver(_ZN6QDebugD1Ev+0x43) [0x8081b73] 12: akonadiserver(_ZN13DbConfigMysql19startInternalServerEv+0x1c27) [0x810c177] 13: akonadiserver(_ZN7Akonadi13AkonadiServer20startDatabaseProcessEv+0xe3) [0x8087a23] 14: akonadiserver(_ZN7Akonadi13AkonadiServerC1EP7QObject+0xca) [0x8088b6a] 15: akonadiserver(_ZN7Akonadi13AkonadiServer8instanceEv+0x48) [0x808a1d8] 16: akonadiserver(main+0x364) [0x8080fb4] 17: /lib/libc.so.6(__libc_start_main+0xe7) [0xb6fabce7] 18: akonadiserver() [0x8080b81] ] " ProcessControl: Application 'akonadiserver' returned with exit code 255 (Unknown error) "akonadiserver" crashed too often and will not be restarted! I tried moving the ~/.local/share/akonadi folder and running it fresh, and I also tried starting Akonadi from a brand new user, all to no avail. Requested by @djeikyb: patches@pleistocene:~$ ls -ld ~/.local drwxrwx--- 3 patches patches 4096 2011-02-07 03:15 /home/patches/.local patches@pleistocene:~$ mysql_upgrade Looking for 'mysql' as: mysql Looking for 'mysqlcheck' as: mysqlcheck Running 'mysqlcheck' with connection arguments: '--port=3306' '--socket=/var/run/mysqld/mysqld.sock' mysqlcheck: Got error: 2002: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) when trying to connect FATAL ERROR: Upgrade failed patches@pleistocene:~$ mysql_upgrade -S ~/.local/share/akonadi/socket-pleistocene/ Looking for 'mysql' as: mysql Looking for 'mysqlcheck' as: mysqlcheck Running 'mysqlcheck' with connection arguments: '--port=3306' '--socket=/var/run/mysqld/mysqld.sock' '--socket=/home/patches/.local/share/akonadi/socket-pleistocene/' mysqlcheck: Got error: 2002: Can't connect to local MySQL server through socket '/home/patches/.local/share/akonadi/socket-pleistocene/' (111) when trying to connect FATAL ERROR: Upgrade failed

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  • C - array count, strtok, etc

    - by Pedro
    Hi... i have a little problem on my code... HI open a txt that have this: LEI;7671;Maria Albertina da silva;[email protected]; 9;8;12;9;12;11;6;15;7;11; LTCGM;6567;Artur Pereira Ribeiro;[email protected]; 6;13;14;12;11;16;14; LEI;7701;Ana Maria Carvalho;[email protected]; 8;13;11;7;14;12;11;16;14; LEI, LTCGM are the college; 7671, 6567, 7701 is student number; Maria, Artur e Ana are the students name; [email protected], ...@gmail are emails from students; the first number of every line is the total of classes that students have; after that is students school notes; example: College: LEI Number: 7671 Name: Maria Albertina da Silva email: [email protected] total of classes: 9 Classe Notes: 8 12 9 12 11 6 15 7 11. My code: typedef struct aluno{ char sigla[5];//college char numero[80];//number char nome[80];//student name char email[20];//email int total_notas;// total of classes char tot_not[40]; // total classes char notas[20];// classe notes int nota; //class notes char situacao[80]; //situation (aproved or disaproved) }ALUNO; void ordena(ALUNO*alunos, int tam)//bubble sort { int i=0; int j=0; char temp[100]; for( i=0;i<tam;i++) for(j=0;j<tam-1;j++) if(strcmp( alunos[i].sigla[j], alunos[i].sigla[j+1])>0){ strcpy(temp, alunos[i].sigla[j]); strcpy(alunos[i].sigla[j],alunos[i].sigla[j+1]); strcpy(alunos[i].sigla[j+1], temp); } } void xml(ALUNO*alunos, int tam){ FILE *fp; char linha[60];//line int soma, max, min, count;//biggest note and lowest note and students per course count float media; //media of notes fp=fopen("example.txt","r"); if(fp==NULL){ exit(1); } else{ while(!(feof(fp))){ soma=0; media=0; max=0; min=0; count=0; fgets(linha,60,fp); if(linha[0]=='L'){ if(ap_dados=strtok(linha,";")){ strcpy(alunos[i].sigla,ap_dados);//copy to struct // i need to call bubble sort here, but i don't know how printf("College: %s\n",alunos[i].sigla); if(ap_dados=strtok(NULL,";")){ strcpy(alunos[i].numero,ap_dados);//copy to struct printf("number: %s\n",alunos[i].numero); if(ap_dados=strtok(NULL,";")){ strcpy(alunos[i].nome, ap_dados);//copy to struct printf("name: %s\n",alunos[i].nome); if(ap_dados=strtok(NULL,";")){ strcpy(alunos[i].email, ap_dados);//copy to struct printf("email: %s\n",alunos[i].email); } } } }i++; } if(isdigit(linha[0])){ if(info_notas=strtok(linha,";")){ strcpy(alunos[i].tot_not,info_notas); alunos[i].total_notas=atoi(alunos[i].tot_not);//total classes for(z=0;z<=alunos[i].total_notas;z++){ if(info_notas=strtok(NULL,";")){ strcpy(alunos[i].notas,info_notas); alunos[i].nota=atoi(alunos[i].notas); // student class notes } soma=soma + alunos[i].nota; media=soma/alunos[i].total_notas;//doesn't work if(alunos[i].nota>max){ max=alunos[i].nota;;//doesn't work } else{ if(min<alunos[i].nota){ min=alunos[i].nota;;//doesn't work } } //now i need to count the numbers of students in the same college, but doesn't work /*If(strcmp(alunos[i].sigla, alunos[i+1].sigla)=0){ count ++; printf("%d\n", count); here for LEI should appear 2 students and for LTCGM appear 1, don't work }*/ //Now i need to see if student is aproved or disaproved // Student is disaproved if he gets 3 notes under 10, how can i do that? } printf("media %d\n",media); //media printf("Nota maxima %d\n",max);// biggest note printf("Nota minima %d\n",min); //lowest note }i++; } } } fclose(fp); } int main(int argc, char *argv[]){ ALUNO alunos; FILE *fp; int tam; fp=fopen(nomeFicheiro,"r"); alunos = (ALUNO*) calloc (tam, sizeof(ALUNO)); xml(alunos,nomeFicheiro, tam); system("PAUSE"); return 0; }

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  • Anatomy of a .NET Assembly - PE Headers

    - by Simon Cooper
    Today, I'll be starting a look at what exactly is inside a .NET assembly - how the metadata and IL is stored, how Windows knows how to load it, and what all those bytes are actually doing. First of all, we need to understand the PE file format. PE files .NET assemblies are built on top of the PE (Portable Executable) file format that is used for all Windows executables and dlls, which itself is built on top of the MSDOS executable file format. The reason for this is that when .NET 1 was released, it wasn't a built-in part of the operating system like it is nowadays. Prior to Windows XP, .NET executables had to load like any other executable, had to execute native code to start the CLR to read & execute the rest of the file. However, starting with Windows XP, the operating system loader knows natively how to deal with .NET assemblies, rendering most of this legacy code & structure unnecessary. It still is part of the spec, and so is part of every .NET assembly. The result of this is that there are a lot of structure values in the assembly that simply aren't meaningful in a .NET assembly, as they refer to features that aren't needed. These are either set to zero or to certain pre-defined values, specified in the CLR spec. There are also several fields that specify the size of other datastructures in the file, which I will generally be glossing over in this initial post. Structure of a PE file Most of a PE file is split up into separate sections; each section stores different types of data. For instance, the .text section stores all the executable code; .rsrc stores unmanaged resources, .debug contains debugging information, and so on. Each section has a section header associated with it; this specifies whether the section is executable, read-only or read/write, whether it can be cached... When an exe or dll is loaded, each section can be mapped into a different location in memory as the OS loader sees fit. In order to reliably address a particular location within a file, most file offsets are specified using a Relative Virtual Address (RVA). This specifies the offset from the start of each section, rather than the offset within the executable file on disk, so the various sections can be moved around in memory without breaking anything. The mapping from RVA to file offset is done using the section headers, which specify the range of RVAs which are valid within that section. For example, if the .rsrc section header specifies that the base RVA is 0x4000, and the section starts at file offset 0xa00, then an RVA of 0x401d (offset 0x1d within the .rsrc section) corresponds to a file offset of 0xa1d. Because each section has its own base RVA, each valid RVA has a one-to-one mapping with a particular file offset. PE headers As I said above, most of the header information isn't relevant to .NET assemblies. To help show what's going on, I've created a diagram identifying all the various parts of the first 512 bytes of a .NET executable assembly. I've highlighted the relevant bytes that I will refer to in this post: Bear in mind that all numbers are stored in the assembly in little-endian format; the hex number 0x0123 will appear as 23 01 in the diagram. The first 64 bytes of every file is the DOS header. This starts with the magic number 'MZ' (0x4D, 0x5A in hex), identifying this file as an executable file of some sort (an .exe or .dll). Most of the rest of this header is zeroed out. The important part of this header is at offset 0x3C - this contains the file offset of the PE signature (0x80). Between the DOS header & PE signature is the DOS stub - this is a stub program that simply prints out 'This program cannot be run in DOS mode.\r\n' to the console. I will be having a closer look at this stub later on. The PE signature starts at offset 0x80, with the magic number 'PE\0\0' (0x50, 0x45, 0x00, 0x00), identifying this file as a PE executable, followed by the PE file header (also known as the COFF header). The relevant field in this header is in the last two bytes, and it specifies whether the file is an executable or a dll; bit 0x2000 is set for a dll. Next up is the PE standard fields, which start with a magic number of 0x010b for x86 and AnyCPU assemblies, and 0x20b for x64 assemblies. Most of the rest of the fields are to do with the CLR loader stub, which I will be covering in a later post. After the PE standard fields comes the NT-specific fields; again, most of these are not relevant for .NET assemblies. The one that is is the highlighted Subsystem field, and specifies if this is a GUI or console app - 0x20 for a GUI app, 0x30 for a console app. Data directories & section headers After the PE and COFF headers come the data directories; each directory specifies the RVA (first 4 bytes) and size (next 4 bytes) of various important parts of the executable. The only relevant ones are the 2nd (Import table), 13th (Import Address table), and 15th (CLI header). The Import and Import Address table are only used by the startup stub, so we will look at those later on. The 15th points to the CLI header, where the CLR-specific metadata begins. After the data directories comes the section headers; one for each section in the file. Each header starts with the section's ASCII name, null-padded to 8 bytes. Again, most of each header is irrelevant, but I've highlighted the base RVA and file offset in each header. In the diagram, you can see the following sections: .text: base RVA 0x2000, file offset 0x200 .rsrc: base RVA 0x4000, file offset 0xa00 .reloc: base RVA 0x6000, file offset 0x1000 The .text section contains all the CLR metadata and code, and so is by far the largest in .NET assemblies. The .rsrc section contains the data you see in the Details page in the right-click file properties page, but is otherwise unused. The .reloc section contains address relocations, which we will look at when we study the CLR startup stub. What about the CLR? As you can see, most of the first 512 bytes of an assembly are largely irrelevant to the CLR, and only a few bytes specify needed things like the bitness (AnyCPU/x86 or x64), whether this is an exe or dll, and the type of app this is. There are some bytes that I haven't covered that affect the layout of the file (eg. the file alignment, which determines where in a file each section can start). These values are pretty much constant in most .NET assemblies, and don't affect the CLR data directly. Conclusion To summarize, the important data in the first 512 bytes of a file is: DOS header. This contains a pointer to the PE signature. DOS stub, which we'll be looking at in a later post. PE signature PE file header (aka COFF header). This specifies whether the file is an exe or a dll. PE standard fields. This specifies whether the file is AnyCPU/32bit or 64bit. PE NT-specific fields. This specifies what type of app this is, if it is an app. Data directories. The 15th entry (at offset 0x168) contains the RVA and size of the CLI header inside the .text section. Section headers. These are used to map between RVA and file offset. The important one is .text, which is where all the CLR data is stored. In my next post, we'll start looking at the metadata used by the CLR directly, which is all inside the .text section.

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  • At most how many customized P3 attributes could be added into Agile?

    - by Jie Chen
    I have one customer/Oracle Partner Consultant asking me such question: how many customized attributes can be allowed to add to Agile's subclass Page Three? I never did research against this because Agile User Guide never says this and theoretically Agile supports unlimited amount of customized attributes, unless the browser itself cannot handle them in allocated memory. However my customers says when to add almost 1000 attributes, the browser (Web Client) will not show any Page Three attributes, including all the out-of-box attributes. Let's see why. Analysis It is horrible to add 1000 attributes manually. Let's do it by a batch SQL like below to add them to Item's subclass Page Three tab. Do not execute below SQL because it will not take effect due to your different node id. CREATE OR REPLACE PROCEDURE createP3Text(v_name IN VARCHAR2) IS v_nid NUMBER; v_pid NUMBER; BEGIN select SEQNODETABLE.nextval into v_nid from dual; Insert Into nodeTable ( id,parentID,description,objType,inherit,helpID,version,name ) values ( v_nid,2473003, v_name ,1,0,0,0, v_name); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,1,0,1,925, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,0,0,0,0,1,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,0,0,0,0,2,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,2,2,0,1,3,'50'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,1,0,1,5, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,2,0,1,6,'50'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,2,0,0,7,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,8,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,9,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,2,1,0,1,10,v_name); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,0,0,0,0,11,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,11743,1,14,'2'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,1,0,1,30, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,1,0,1,38, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,451,0,59,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,451,0,60,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,724,0,61, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,2,1,0,0,232,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,451,0,233,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,12239,1,415,'13307'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,2,1,0,0,605,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,610,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,451,0,716,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,795,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,2000008821,1,864,'2'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,923,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,0,719,'0'); Insert Into tableInfo ( tabID,tableID,classID,att,ordering ) values ( 2473005,1501,2473002,v_nid,9999); commit; END createP3Text; / BEGIN FOR i in 1..1000 LOOP createP3Text('MyText' || i); END LOOP; END; / DROP PROCEDURE createP3Text; COMMIT; Now restart Agile Server and check the Server's log, we noticed below: ***** Node Created : 85625 ***** Property Created : 184579 +++++++++++++++++++++++++++++++++++++ + Agile PLM Server Starting Up... + +++++++++++++++++++++++++++++++++++++ However the previously log before batch SQL is ***** Node Created : 84625 ***** Property Created : 157579 +++++++++++++++++++++++++++++++++++++ + Agile PLM Server Starting Up... + +++++++++++++++++++++++++++++++++++++ Obviously we successfully imported 1000 (85625-84625) attributes. Now go to JavaClient and confirm if we have them or not. Theoretically we are able to open such item object and see all these 1000 attributes and their values, but we get below error. We have no error tips in server log. But never mind we have the Java Console for JavaClient. If to open the same item in JavaClient we get a clear error and detailed trace in Java Console. ORA-01795: maximum number of expressions in a list is 1000 java.sql.SQLException: ORA-01795: maximum number of expressions in a list is 1000 at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:125) ... ... at weblogic.jdbc.wrapper.PreparedStatement.executeQuery(PreparedStatement.java:128) at com.agile.pc.cmserver.base.AgileFlexUtil.setFlexValuesForOneRowTable(AgileFlexUtil.java:1104) at com.agile.pc.cmserver.base.BaseFlexTableDAO.loadExtraFlexAttValues(BaseFlexTableDAO.java:111) at com.agile.pc.cmserver.base.BasePageThreeDAO.loadTable(BasePageThreeDAO.java:108) If you are interested in the background of the problem, you may de-compile the class com.agile.pc.cmserver.base.AgileFlexUtil.setFlexValuesForOneRowTable and find the root cause that Agile happens to hit Oracle Database's limitation that more than 1000 values in the "IN" clause. Check here http://ora-01795.ora-code.com If you need Oracle Agile's final solution, please contact Oracle Agile Support. Performance Below two screenshot are jvm heap usage from before-SQL and after-SQL. We can see there is no big memory gap between two cases. So definitely there is no performance impact to Agile Application Server unless you have more than 1000 attributes for EACH of your dozens of  subclasses. And for client, 1000 attributes should not impact the browser's performance because in HTML we only use dt and dd for each attribute's pair: label and value. It is quite lightweight.

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  • More Fun With Math

    - by PointsToShare
    More Fun with Math   The runaway student – three different ways of solving one problem Here is a problem I read in a Russian site: A student is running away. He is moving at 1 mph. Pursuing him are a lion, a tiger and his math teacher. The lion is 40 miles behind and moving at 6 mph. The tiger is 28 miles behind and moving at 4 mph. His math teacher is 30 miles behind and moving at 5 mph. Who will catch him first? Analysis Obviously we have a set of three problems. They are all basically the same, but the details are different. The problems are of the same class. Here is a little excursion into computer science. One of the things we strive to do is to create solutions for classes of problems rather than individual problems. In your daily routine, you call it re-usability. Not all classes of problems have such solutions. If a class has a general (re-usable) solution, it is called computable. Otherwise it is unsolvable. Within unsolvable classes, we may still solve individual (some but not all) problems, albeit with different approaches to each. Luckily the vast majority of our daily problems are computable, and the 3 problems of our runaway student belong to a computable class. So, let’s solve for the catch-up time by the math teacher, after all she is the most frightening. She might even make the poor runaway solve this very problem – perish the thought! Method 1 – numerical analysis. At 30 miles and 5 mph, it’ll take her 6 hours to come to where the student was to begin with. But by then the student has advanced by 6 miles. 6 miles require 6/5 hours, but by then the student advanced by another 6/5 of a mile as well. And so on and so forth. So what are we to do? One way is to write code and iterate it until we have solved it. But this is an infinite process so we’ll end up with an infinite loop. So what to do? We’ll use the principles of numerical analysis. Any calculator – your computer included – has a limited number of digits. A double floating point number is good for about 14 digits. Nothing can be computed at a greater accuracy than that. This means that we will not iterate ad infinidum, but rather to the point where 2 consecutive iterations yield the same result. When we do financial computations, we don’t even have to go that far. We stop at the 10th of a penny.  It behooves us here to stop at a 10th of a second (100 milliseconds) and this will how we will avoid an infinite loop. Interestingly this alludes to the Zeno paradoxes of motion – in particular “Achilles and the Tortoise”. Zeno says exactly the same. To catch the tortoise, Achilles must always first come to where the tortoise was, but the tortoise keeps moving – hence Achilles will never catch the tortoise and our math teacher (or lion, or tiger) will never catch the student, or the policeman the thief. Here is my resolution to the paradox. The distance and time in each step are smaller and smaller, so the student will be caught. The only thing that is infinite is the iterative solution. The race is a convergent geometric process so the steps are diminishing, but each step in the solution takes the same amount of effort and time so with an infinite number of steps, we’ll spend an eternity solving it.  This BTW is an original thought that I have never seen before. But I digress. Let’s simply write the code to solve the problem. To make sure that it runs everywhere, I’ll do it in JavaScript. function LongCatchUpTime(D, PV, FV) // D is Distance; PV is Pursuers Velocity; FV is Fugitive’ Velocity {     var t = 0;     var T = 0;     var d = parseFloat(D);     var pv = parseFloat (PV);     var fv = parseFloat (FV);     t = d / pv;     while (t > 0.000001) //a 10th of a second is 1/36,000 of an hour, I used 1/100,000     {         T = T + t;         d = t * fv;         t = d / pv;     }     return T;     } By and large, the higher the Pursuer’s velocity relative to the fugitive, the faster the calculation. Solving this with the 10th of a second limit yields: 7.499999232000001 Method 2 – Geometric Series. Each step in the iteration above is smaller than the next. As you saw, we stopped iterating when the last step was small enough, small enough not to really matter.  When we have a sequence of numbers in which the ratio of each number to its predecessor is fixed we call the sequence geometric. When we are looking at the sum of sequence, we call the sequence of sums series.  Now let’s look at our student and teacher. The teacher runs 5 times faster than the student, so with each iteration the distance between them shrinks to a fifth of what it was before. This is a fixed ratio so we deal with a geometric series.  We normally designate this ratio as q and when q is less than 1 (0 < q < 1) the sum of  + … +  is  – 1) / (q – 1). When q is less than 1, it is easier to use ) / (1 - q). Now, the steps are 6 hours then 6/5 hours then 6/5*5 and so on, so q = 1/5. And the whole series is multiplied by 6. Also because q is less than 1 , 1/  diminishes to 0. So the sum is just  / (1 - q). or 1/ (1 – 1/5) = 1 / (4/5) = 5/4. This times 6 yields 7.5 hours. We can now continue with some algebra and take it back to a simpler formula. This is arduous and I am not going to do it here. Instead let’s do some simpler algebra. Method 3 – Simple Algebra. If the time to capture the fugitive is T and the fugitive travels at 1 mph, then by the time the pursuer catches him he travelled additional T miles. Time is distance divided by speed, so…. (D + T)/V = T  thus D + T = VT  and D = VT – T = (V – 1)T  and T = D/(V – 1) This “strangely” coincides with the solution we just got from the geometric sequence. This is simpler ad faster. Here is the corresponding code. function ShortCatchUpTime(D, PV, FV) {     var d = parseFloat(D);     var pv = parseFloat (PV);     var fv = parseFloat (FV);     return d / (pv - fv); } The code above, for both the iterative solution and the algebraic solution are actually for a larger class of problems.  In our original problem the student’s velocity (speed) is 1 mph. In the code it may be anything as long as it is less than the pursuer’s velocity. As long as PV > FV, the pursuer will catch up. Here is the really general formula: T = D / (PV – FV) Finally, let’s run the program for each of the pursuers.  It could not be worse. I know he’d rather be eaten alive than suffering through yet another math lesson. See the code run? Select  “Catch Up Time” in www.mgsltns.com/games.htm The host is running on Unix, so the link is case sensitive. That’s All Folks

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