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  • How to receive packets on the MCU's serial port?

    - by itisravi
    Hello, Consider this code running on my microcontroller unit(MCU): while(1){ do_stuff; if(packet_from_PC) send_data_via_gpio(new_packet); //send via general purpose i/o pins else send_data_via_gpio(default_packet); do_other_stuff; } The MCU is also interfaced to a PC via a UART.Whenever the PC sends data to the MCU, the *new_packet* is sent, otherwise the *default_packet* is sent.Each packet can be 5 or more bytes with a pre defined packet structure. My question is: 1.Should i receive the entire packet from PC using inside the UART interrut service routine (ISR)? In this case, i have to implement a state machine inside the ISR to assemble the packet (which can be lengthy with if-else or switch-case blocks). 2.Detect a REQUEST command (one byte)from the PC in my ISR set a flag, diable UART interrupt alone and form the packet in my while(1) loop by polling the UART?

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  • whats a sure shot way to make sure objects appear correctly positioned on stage

    - by dubbeat
    Hi, I've being having a lot of trouble recently getting objects (UIComponents containing movieclips) to appear correctly in the right positions. For example, my current dilema is I have a container that is 3 layers deep. outer layer inner layer display layer This hiearachy was built in CS4 as a movieclip. In the display layer in CS4 I figured out where I want to place 16 different "box" movieclips. I dont want to create these boxes maunually at design time, instead I want to add them at run time. So I know what container I want to add my boxes to. I know what positions they "would" be at in CS4 environment. Whats the best way to add them in the correct locations with code? The "box" I'm trying to add in a movieclip held inside of a UIComponent. Is there a "rule of thumb" to do this type of thing? I'm sure I'm going to encounter this problem again and again and I'd like to just blow the problem out of the water once and for all with the "right way" to do this.

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  • Calculating distance between two X,Y coordinates

    - by Umopepisdn
    I am writing a tool for a game that involves calculating the distance between two coordinates on a spherical plane 500 units across. That is, [0,0] through [499,499] are valid coordinates, and [0,0] and [499,499] are also right next to each other. Currently, in my application, I am comparing the distance between a city with an [X,Y] location respective to the user's own [X,Y] location, which they have configured in advance. To do this, I found this algorithm, which kind of works: Math.sqrt ( dx * dx + dy * dy ); Because sorting a paged list by distance is a useful thing to be able to do, I implemented this algorithm in a MySQL query and have made it available to my application using the following part of my SELECT statement: SQRT( POW( ( ".strval($sourceX)." - cityX ) , 2 ) + POW( ( ".strval($sourceY)." - cityY ) , 2 ) ) AS distance This works fine for many calculations, but does not take into account the fact that [0,0] and [499,499] are kitty-corner to one another. Is there any way I can tweak this algorithm to generate an accurate distance, given that 0 and 499 are adjacent? Thanks, -Umo

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  • Performance analytics via DBMS "plugins", or other solution

    - by Polynomial
    I'm working on a systems monitoring product that currently focuses on performance at the system level. We're expanding out to monitoring database systems. Right now we can fetch simple performance information from a selection of DBMS, like connection count, disk IO rates, lock wait times, etc. However, we'd really like a way to measure the execution time of every query going into a DBMS, without requiring the client to implement monitoring in their application code. Some potential solutions might be: Some sort of proxy that sits between client and server. SSL might be an issue here, plus it requires us to reverse engineer and implement the network protocol for each DBMS. Plugin for each DBMS system that automatically records performance information when a query comes in. Other problems include "anonymising" the SQL, i.e. taking something like SELECT * FROM products WHERE price > 20 AND name LIKE "%disk%" and producing SELECT * FROM products WHERE price > ? AND name LIKE "%?%", though this shouldn't be too difficult with some clever parsing and regex. We're mainly focusing on: MySQL MSSQL Oracle Redis mongodb memcached Are there any plugin-style mechanisms we can utilise for any of these? Or is there a simpler solution?

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  • How do I fix issue causing "incomplete startup packet" log message trying to implement replication in Postgresql?

    - by colour me brad
    I've got two cloud servers running Ubuntu 13.04 and PostgreSQL 9.2. I've primarily used this blog post to aid me in setting things up. However, to do the initial database dump to the slave I'm using pg_start_backup/pg_stop_backup strategy used in this other blog post. I've read through the docs and postgres wikis as well. I ran into several problems I was able to solve, but I can't get past this wretched "the database is starting up" failure. I'm not sure if seeing "cp: cannot stat '/var/lib/postgresql/9.2/archive/00000001000000000000003A': No such file or directory" after "consistent recover state reached" is normal or the first sign of a problem. The searching I've done on "the database is starting up" and "incomplete startup packet" tells me that something is sending empty TCP packets to the slave. The only thing that even knows about the slave is the master, so I'm not sure why it's sending empty packets... Has anyone worked with this and have an idea what might be going wrong? The postgres log on the slave looks like so: 2013-08-26 13:01:38 CDT LOG: entering standby mode 2013-08-26 13:01:38 CDT LOG: restored log file "000000010000000000000039" from archive 2013-08-26 13:01:38 CDT LOG: incomplete startup packet 2013-08-26 13:01:39 CDT LOG: redo starts at 0/39000020 2013-08-26 13:01:39 CDT LOG: consistent recovery state reached at 0/390000E0 cp: cannot stat '/var/lib/postgresql/9.2/archive/00000001000000000000003A': No such file or directory 2013-08-26 13:01:39 CDT LOG: streaming replication successfully connected to primary 2013-08-26 13:01:39 CDT FATAL: the database system is starting up 2013-08-26 13:01:39 CDT FATAL: the database system is starting up 2013-08-26 13:01:40 CDT FATAL: the database system is starting up 2013-08-26 13:01:40 CDT FATAL: the database system is starting up 2013-08-26 13:01:41 CDT FATAL: the database system is starting up 2013-08-26 13:01:42 CDT FATAL: the database system is starting up 2013-08-26 13:01:42 CDT FATAL: the database system is starting up 2013-08-26 13:01:43 CDT FATAL: the database system is starting up 2013-08-26 13:01:43 CDT FATAL: the database system is starting up 2013-08-26 13:01:44 CDT FATAL: the database system is starting up 2013-08-26 13:01:44 CDT FATAL: the database system is starting up 2013-08-26 13:01:44 CDT LOG: incomplete startup packet 2013-08-26 13:03:27 CDT FATAL: the database system is starting up 2013-08-26 13:03:27 CDT FATAL: the database system is starting up 2013-08-26 13:03:30 CDT FATAL: the database system is starting up 2013-08-26 13:03:30 CDT FATAL: the database system is starting up thanks! brad

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  • Server Performance

    - by sb12
    I know very little about performance tuning of servers etc... so i thought i'd put this up here as i start some research on it, just to get some direction. I am in the process of migrating from my old server to a new one - both are 64 bit machines. One is a few years old, the other brand new (PowerEdge R410). The old server spec is: 2 cpus, 3.4GHz Pentiums, 8G of RAM, Fedora 11 currently installed The new server spec is: 16 cpus, 3.2 GHz Xeon, 16G of RAM, CentOS 6.2 installed. Also RAID10 is on the new server - no RAID on the old one. Both servers currently have the same database (MySQL) with the same data migrated. I wrote a Perl script that simply steps through each row of a table in the database (about 18000 rows) and updates a value in that row. Every row in the table is updated. Out of curiosity i ran this perl script on both machines, just to see how the new server would perform vs. the old one, and it produced interesting results: The old server was twice as fast as the new one to complete. Looking at the database, both are configured exactly the same (the new one being a dump of the old one...)... Anyone any ideas why this would be given the hardware gap between both? As i said i'm about to start some digging, but thought i'd put this up here to maybe get some good direction.... Many thanks in advance..

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  • MySQL server stopped working after upgrade

    - by umpirsky
    I upgraded to 12.04 and my MySQL server just stopped working. It throws: ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) I tried to reinstall it from software center, but it fails with: Package operation failed The installation or removal of a software package failed. installArchives() failed: Selecting previously unselected package mysql-server. (Reading database ... (Reading database ... 5% (Reading database ... 10% (Reading database ... 15% (Reading database ... 20% (Reading database ... 25% (Reading database ... 30% (Reading database ... 35% (Reading database ... 40% (Reading database ... 45% (Reading database ... 50% (Reading database ... 55% (Reading database ... 60% (Reading database ... 65% (Reading database ... 70% (Reading database ... 75% (Reading database ... 80% (Reading database ... 85% (Reading database ... 90% (Reading database ... 95% (Reading database ... 100% (Reading database ... 243412 files and directories currently installed.) Unpacking mysql-server (from .../mysql-server_5.5.22-0ubuntu1_all.deb) ... Setting up mysql-server-5.5 (5.5.22-0ubuntu1) ... start: Job failed to start invoke-rc.d: initscript mysql, action "start" failed. dpkg: error processing mysql-server-5.5 (--configure): subprocess installed post-installation script returned error exit status 1 No apport report written because MaxReports is reached already dpkg: dependency problems prevent configuration of mysql-server: mysql-server depends on mysql-server-5.5; however: Package mysql-server-5.5 is not configured yet. dpkg: error processing mysql-server (--configure): dependency problems - leaving unconfigured No apport report written because MaxReports is reached already Errors were encountered while processing: mysql-server-5.5 mysql-server Error in function: Setting up mysql-server-5.5 (5.5.22-0ubuntu1) ... start: Job failed to start invoke-rc.d: initscript mysql, action "start" failed. dpkg: error processing mysql-server-5.5 (--configure): subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of mysql-server: mysql-server depends on mysql-server-5.5; however: Package mysql-server-5.5 is not configured yet. dpkg: error processing mysql-server (--configure): dependency problems - leaving unconfigured I also tried: $ sudo apt-get install -f Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: mysql-server-5.5 mysql-server-core-5.5 Use 'apt-get autoremove' to remove them. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 1 not fully installed or removed. After this operation, 0 B of additional disk space will be used. Setting up mysql-server-5.5 (5.5.22-0ubuntu1) ... start: Job failed to start invoke-rc.d: initscript mysql, action "start" failed. dpkg: error processing mysql-server-5.5 (--configure): subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: mysql-server-5.5 E: Sub-process /usr/bin/dpkg returned an error code (1) Any idea? EDIT: Crash report is being auto generated. EDIT: After trying and trying I got suggestion to do: #apt-get --purge remove mysql-server-5.1 mysql-server-5.5 Reading package lists... Done Building dependency tree Reading state information... Done Virtual packages like 'mysql-server-5.1' can't be removed The following packages will be REMOVED: mysql-server-5.5* 0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded. 1 not fully installed or removed. After this operation, 31.3 MB disk space will be freed. Do you want to continue [Y/n]? Y (Reading database ... 243407 files and directories currently installed.) Removing mysql-server-5.5 ... Purging configuration files for mysql-server-5.5 ... Processing triggers for ureadahead ... Processing triggers for man-db ... The most important part is: Virtual packages like 'mysql-server-5.1' can't be removed Any idea?

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  • Need help tuning Mysql and linux server

    - by Newtonx
    We have multi-user application (like MailChimp,Constant Contact) . Each of our customers has it's own contact's list (from 5 to 100.000 contacts). Everything is stored in one BIG database (currently 25G). Since we released our product we have the following data history. 5 years of data history : - users/customers (200+) - contacts (40 million records) - campaigns - campaign_deliveries (73.843.764 records) - campaign_queue ( 8 millions currently ) As we get more users and table records increase our system/web app is getting slower and slower . Some queries takes too long to execute . SCHEMA Table contacts --------------------+------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +---------------------+------------------+------+-----+---------+----------------+ | contact_id | int(10) unsigned | NO | PRI | NULL | auto_increment | | client_id | int(10) unsigned | YES | | NULL | | | name | varchar(60) | YES | | NULL | | | mail | varchar(60) | YES | MUL | NULL | | | verified | int(1) | YES | | 0 | | | owner | int(10) unsigned | NO | MUL | 0 | | | date_created | date | YES | MUL | NULL | | | geolocation | varchar(100) | YES | | NULL | | | ip | varchar(20) | YES | MUL | NULL | | +---------------------+------------------+------+-----+---------+----------------+ Table campaign_deliveries +---------------+------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +---------------+------------------+------+-----+---------+----------------+ | id | int(11) | NO | PRI | NULL | auto_increment | | newsletter_id | int(10) unsigned | NO | MUL | 0 | | | contact_id | int(10) unsigned | NO | MUL | 0 | | | sent_date | date | YES | MUL | NULL | | | sent_time | time | YES | MUL | NULL | | | smtp_server | varchar(20) | YES | | NULL | | | owner | int(5) | YES | MUL | NULL | | | ip | varchar(20) | YES | MUL | NULL | | +---------------+------------------+------+-----+---------+----------------+ Table campaign_queue +---------------+------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +---------------+------------------+------+-----+---------+----------------+ | queue_id | int(10) unsigned | NO | PRI | NULL | auto_increment | | newsletter_id | int(10) unsigned | NO | MUL | 0 | | | owner | int(10) unsigned | NO | MUL | 0 | | | date_to_send | date | YES | | NULL | | | contact_id | int(11) | NO | MUL | NULL | | | date_created | date | YES | | NULL | | +---------------+------------------+------+-----+---------+----------------+ Slow queries LOG -------------------------------------------- Query_time: 350 Lock_time: 1 Rows_sent: 1 Rows_examined: 971004 SELECT COUNT(*) as total FROM contacts WHERE (contacts.owner = 70 AND contacts.verified = 1); Query_time: 235 Lock_time: 1 Rows_sent: 1 Rows_examined: 4455209 SELECT COUNT(*) as total FROM contacts WHERE (contacts.owner = 2); How can we optimize it ? Queries should take no more than 30 secs to execute? Can we optimize it and keep all data in one BIG database or should we change app's structure and set one single database to each user ? Thanks

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  • How will I support 100,000 requests an hour?!

    - by tylerl
    I know this question is a little strange but I got lucky with an idea and I need some numbers to use for when I try to make a deal with a company. I'm wondering how much it'll cost me to run a site that's heavy on PHP and gets between 70,000 and 100,000 requests an hour on something like Rackspace's Cloud Servers. I have no idea how many servers I need or how much RAM each one should have. There will be a decent number of images on the site (probably something like 10,000 in the first couple weeks) and the site runs on about 2,500 lines of PHP code. I figure I should sign up for a CDN of some kind, although CDN In A Box is all I've heard of and I'm not sure it's necessary for a site that's already on a cloud platform. I've obviously never done anything like this before so I'm just looking to get an estimation of what I need for this massive site... Also, I use a database and I was wondering how that works - would I dedicate one of the cloud servers to running the database or would I need to put the database into each of the cloud servers? Thanks in advance...

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  • Benefits and features of different requirements-management systems and tools available?

    - by Gnark
    I am looking for a good comparision of different available professionial requirement managment tools. I am especially interested in the the features available within the different software solutions. Additionally to the "obvious" features I am looking for a proffesional Requirement Management System that supports for: multi-lingual customizable generation of documentation & history (graphs) search features (e.g. fulltext for comments), ordering, priorities version history bi-directional traceability of changes, artefacts, requirements, changes in requirements, etc. Any kind of integration of V-Model XT would be a really-nice-to-have-feature... Besides, I'd like to hear any personal motivated recommendations and/or experiences with different requirement management systems. Any input is highly appreciated. content consulted : similar question reqm tool with v-model nice, but too old paper (pdf) Tools Journal

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  • Benefits and features of different requirements-management systems and tools available?

    - by DevDevDave
    I am looking for a good comparision of different available professional requirement management tools. I am especially interested in the the features available within the different software solutions. Additionally to the "obvious" features I am looking for a proffesional Requirement Management System that supports for: multi-lingual customizable generation of documentation & history (graphs) search features (e.g. fulltext for comments), ordering, priorities version history bi-directional traceability of changes, artefacts, requirements, changes in requirements, etc. Any kind of integration of V-Model XT would be a really-nice-to-have-feature. Besides, I'd like to hear any personal motivated recommendations and/or experiences with different requirement management systems. Any input is highly appreciated. Content consulted: similar question reqm tool with v-model ToolsJournal.com nice, but too old paper (pdf)

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  • MySQL Error: FUNCTION LEVENSHTEIN already exists

    - by kgrote
    I've got an ExpressionEngine database and I exported a couple of tables from it, then dropped those tables. When I try to re-import the tables in PHPMyAdmin, I get this error: SQL query: -- -- Database: `my_db` -- DELIMITER $$ -- -- Functions -- CREATE DEFINER=`my_username`@`%` FUNCTION `LEVENSHTEIN`(s1 VARCHAR(255), s2 VARCHAR(255)) RETURNS int(11) DETERMINISTIC BEGIN DECLARE s1_len, s2_len, i, j, c, c_temp, cost INT; DECLARE s1_char CHAR; DECLARE cv0, cv1 VARBINARY(256); SET s1_len = CHAR_LENGTH(s1), s2_len = CHAR_LENGTH(s2), cv1 = 0x00, j = 1, i = 1, c = 0; IF s1 = s2 THEN RETURN 0; ELSEIF s1_len = 0 THEN RETURN s2_len; ELSEIF s2_len = 0 THEN RETURN s1_len; ELSE WHILE j <= s2_len DO SET cv1 = CONCAT(cv1, UNHEX(HEX(j))), j = j + 1; END WHILE; WHILE i <= s1_len DO SET s1_char = SUBSTRING(s1, i, 1), c = i, cv0 = UNHEX(HEX(i)), j = 1; WHILE j <= s2_len DO SET c = c + 1; IF s1_char = SUBSTRING(s2, j, 1) THEN SET cost = 0; ELSE SET cost = 1; END IF; SET c_temp = CONV(HEX(SUBSTRING(cv1, j, 1)), 16, 10) + cost; IF c > c_temp THEN SET c = [...] MySQL said: Documentation #1304 - FUNCTION LEVENSHTEIN already exists I get this error even if I drop all tables from the DB and try to import anything. The only way I can get the error to go away is to totally delete the database and re-create it. What's causing that error and how can I stop it from happening?

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  • what are the best concert-ticket systems? comercial and open source

    - by helle
    can anybody recommend (of developers-opinion) such systems, where you can book tickets for concerts, conferences, etc. one should be able to book a seat as well, and it shell do the debitcard stuff, and has a good interface for accounting. I am looking for an open source solution, but I am also interested in commercial ones, to have a comparison of features and prices, etc. thanks for everybodys suggestions - pros and cons to it are very wellcome ;) well, it shouldn't has a flash component multi languages :) would be great an extra mobile-view is preferred the extra extra bonus for such a system would be a very good wordpress compatibility p.s. sorry for my english well ... I already googled a lot. But I found so very many, that I hope you could help me to find a good choice, to have a base from where I can do a further lookup. and for sure :) What are the things you I have to have in mind. What brings troubles, what brings costs?

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  • How to publish internal data to the internet - as simple as possible

    - by mlarsen
    I Asked this at Staock Overflow, but I would like your oppinion too as it has as much to do with administration as it does with coding. We have a .net 2-tier application where a desktop program is talking to a database. We support MS SQL Server 2000, 2005, 2008 and Oracle 9, 10 and 11. The application is sold, not as shrink-wrap, but pretty close. It is quite important for us that the installation and configuration is as easy as possible as installation instructions are usually supplied in written form to the customers internal IT-department. Our application is usually not seen as mission critical for the IT-department, so we need to keep their work down to a minimum. Now we are starting to get wishes for a web application build on top of the same data. The web application will be hosted by us and delivered as a SaaS application. Now the challenge is how to move data back and forth between the web application and the customers internal database. as I see it we have some requirements: We must be ready to handle the situation where the customers database is not accessible from the DMZ. I guess the easiest solution is that all communication is initiated from inside the customers lan. As little firewall configuration as possible. The best is if we can run without any special configuration as long as outgoing traffic from the customers lan are not blocked. If we need something changed in the firewall, we must be able to document that the change is secure. It doesn't have to be real time. Moving data in batches every ten minutes or so is OK. Data moves both ways, but not the same tables, so we don't have to support merges. It would be nice if we don't have to roll our own framework completely. Looking forward to hear your suggestions.

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  • Web Platform Installer issues deploying Azure SDK 1.4 on refreshed systems.

    - by Enrique Lima
    Recently I have been doing quite a bit of testing on different means to deploy the Azure SDKs and such. After a very successful couple of systems, I started running into issues last night. Here is the problem, if I go to the Windows Azure Website, and go to Develop, then click on the SDK and Tools, then Get Tools & SDK, it launches the Web Platform Installer.  All seems well at that point, except it will go through the initial process, will find the SDK files for 1.4, but since the tools for Visual Studio are still 1.3, the location throws back a 404, which causes the Installer to fail.  NOTE:If you already had SDK 1.3 and the tools in place, it will go through. The fix is to go directly to the Microsoft Download Center location and download the files.  Here is the link … http://www.microsoft.com/downloads/en/details.aspx?FamilyID=7a1089b6-4050-4307-86c4-9dadaa5ed018

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  • Is installing Rational Developer for Power Systems on Ubuntu recommended?

    - by ZS6JCE
    I am interested in installing Rational Developer for Power 8.0.3 (RDPi) on Ubuntu 12.04. I would like to know if other Ubuntu users have run into issues? Is it recommended or should I just stick to using RDPi in Windows 7 in VirtualBox? I have done some research, but could not divine a solution. From IBM's Developerworks website: Ubuntu clients are obviously missing from the list. While not officially supported, we have had some success in running ... on Ubuntu 10.04 LTS and later. Detailed installation instructions for the supported operation systems can be found here.

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  • best approach to learning for an undergrad operating systems course?

    - by rrazd
    what is the best approach to learning for an undergrad operating systems course in order to understand the concepts and get a good grade in the exam? I know that some courses can be mastered through diligently reading the textbook or attending lectures while for others the concepts can only be understood by doing hands on projects. Is there a general studying approach that should be adopted for this type of a course? I know this may be subjective but I am looking for personal experiences/study methods by those who have taken similar courses to see if there is one particular method that worked well for the majority.

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  • Poll: How long will you wait before using Solaris 11 on production systems?

    - by nospam(at)example.com (Joerg Moellenkamp)
    When Sun released Solaris 10, it was my first migration phase to a new Solaris major release while being part of Sun. At that time i heard a lot of comments between "Oh, we will install it on new systems on day 1" to "oh ... not that fast ... we will wait ... we are not that fast ... we will do it in a year". I would like to get some additional insight and so i set up the poll plugin for s9y to get the answer to the question "How long will you wait before using Solaris 11 on production system?". Thank you for your participation!

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  • Result of the "How long do you wait before Solaris 11 gets on your prod systems?"

    - by nospam(at)example.com (Joerg Moellenkamp)
    I just removed the poll at 10:52, so this is the final result: My conclusions out of it: While the removal of UltraSPARC I to VI+ support in Solaris 11 may hit some of the people voting in the categories "Wait?" to "6 month", most of the users keep Solaris 10 running on their existing system anyway or migrate that late that even the newest system have reached their end-of-service-live or are near of it, so a migration doesn't sound that feasible. So i assume Product Management was right with their decision to remove the support in order to make the feature i can't talk of possible, as i don't think that many of the early migrators are still using the system in question, as most systems have reached EOSL. Didn't thought that there would be people waiting three years and more ...

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  • Hosting options for data-enabled web application

    - by Hertfordian
    I am independently developing an asp.net business application with a MySQL database. I currently have a Windows web hosting account which includes MySQL and MS SQL as installed supported options. I am not yet finally committed to using MySQL and I want to keep my options open to evaluate MS SQL and possibly other options such as PostGreSQL later when more of the business logic is in place - my data access layer will handle the database connectivity. The web hosting setup I have now is fine for development purposes, but if in future I want to use, say, PostGreSQL Server, and a level of usage of, say, 10,000 hits per day concentrated in business hours, I'm assuming I'll need a dedicated server. But in that case, should I just install PostGreSQL on the dedicated server, or is best practice to have a separate database server - perhaps locked down so that it can only be accessed through the web server? And supposing it was only 2000 hits a day - how would that change things? I'd appreciate it if anyone could point me in the direction of a useful guide to these sorts of issues. Naturally if I start paying for separate servers, I would like to know exactly why I'm doing it and what the performance issues and thresholds are.

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  • Calculating memory footprints using /proc/sysvipc/shm

    - by MarkTeehan
    This is for a SLES 10 database server. One of my servers runs three databases and three app servers; I am analyzing how their shared memory segments grow and shrink to avoid intermittent out-of-memory scenarios. "Top" is hot helpful for this since its calculations for RES and VIRT are inconsistent. I am doing this by matching up the contents of /proc/sysvipc/shm with memory usage reported by the database admin console. I do this by totaling up saving the contents of /proc/sysvipc/shm and then total up "bytes" for all of the segments for the offending userid. This is a large server with hundreds of segments and tens (or hundreds) of GB of allocated memory per userid. However it doesn't match up - the database management software claims to be using around 25% more memory than the total I calculate. Negligible swap space is in use, so I am ignoring that. I am running it as root so I am sure I see all shared memory segments. My question is : is all (significant) allocated memory recorded in /proc/sysvipc/shm, or is this only shared memory (*and not "un-shared" memory?). If this is incorrect, what is the correct way to calculate out the total allocated memory for each userid? Also: I believe doing a 'cat' on this file locks server IPC. I check it every 5 seconds - is it likely that this frequency could be problematic? Thanks! Mark Teehan Singapore

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  • Excel 2013: VLookup for cells that share common characters within cell but are both surrounded by other non-matching text

    - by Kylie Z
    I am pulling information from 2 different databases. The databases use different naming protocol for the exact same item/specified placement however they always have certain components of the name in common. The length of these names can vary throughout each of the databases (see the pic below) so I don't think counting characters would help. I need a formula (probably a vlookup/match/index of some sort) to pair up the names from the 2nd database name with the 1st database name and then place it in the adjacent column(B2) on sheet1. Until this point I've had to match, copy, and paste the pairs manually from one sheet to the other and it takes FOREVER. Any help would be much appreciated!!! For example: Database1 Name in Sheet1,A2: 728x90_Allstate_629930_ALL_JUL_2013_MASSACHUSETTSAUTO_BAN_MSN_ROSMSNAUTOSMASSACHUSETTS_7.2.13 Database2 Name in Sheet2, A13: BAN_MSN_ROSMSNAUTOSMASSACHUSETTS728X90_728X90_DFA Common Factors: "ROSMSNAUTOSMASSACHUSETTS" & "728X90" Therefore A2 and A13 need to pair up In some cases, Database 1 and 2 will have a common name aspect but sizing will be different. They need to have BOTH aspects in common in order to be paired so I would NOT want the below example to pair up. Database1 Name in Sheet1,A2: 728x90_Allstate_629930_ALL_JUL_2013_MASSACHUSETTSAUTO_BAN_MSN_ROSMSNAUTOSMASSACHUSETTS_7.2.13 Database2 Name in Sheet2, A12: BAN_MSN_ROSMSNAUTOSMASSACHUSETTS300X250_300X250_DFA Common Factor: Only "ROSMSNAUTOSMASSACHUSETTS" matches. "728x90" is not equal to "300X250" - Sizing is different so they should not be paired.

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  • How to handle ViewModel and Database in C#/WPF/MVVM App

    - by Mike B
    I have a task management program with a "Urgency" field. Valid values are Int16 currently mapped to 1 (High), 2 (Medium), 3 (Low), 4 (None) and 99 (Closed). The urgency field is used to rank tasks as well as alter the look of the items in the list and detail view. When a user is editing or adding a new task they select or view the urgency in a ComboBox. A Converter passes Strings to replace the Ints. The urgency collection is so simple I did not make it a table in the database, instead it is a, ObservableCollection(Int16) that is populated by a method. Since the same screen may be used to view a closed task the "Closed" urgency must be in the ItemsSource but I do not want the user to be able to select it. In order to prevent the user from being able to select that item in the ComboBox but still be able to see it if the item in the database has that value should I... Manually disable the item in the ComboBox in code or Xaml (I doubt it) Change the Urgency collection from an Int16 to an Object with a Selectable Property that the isEnabled property of the ComboBoxItem Binds to. Do as in 2 but also separate the urgency information into its own table in the database with a foreign key in the Tasks table None of the above (I suspect this is the correct answer) I ask this because this is a learning project (My first real WPF and first ever MVVM project). I know there is rarely one Right way to do something but I want to make sure I am learning in a reasonable manner since it if far harder to Unlearn bad habits Thanks Mike

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  • Javascript html5 database transaction problem in loops

    - by Marek
    I'm hittig my head on this and i will be glad for any help. I need to store in a database a context (a list of string ids) for another page. I open a page with a list of artworks and this page save into the database those artowrks ids. When i click on an artwork i open its webpage but i can access the database to know the context and refer to the next and prev artwork. This is my code to retrieve the contex: updateContext = function () { alert("updating context"); try { mydb.transaction( function(transaction) { transaction.executeSql("select artworks.number from artworks, collections where collections.id = artworks.section_id and collections.short_name in ('cro', 'cra', 'crp', 'crm');", [], contextDataHandler, errorHandler); }); } catch(e) { alert(e.message); } } the contextDatahandler function then iterates through the results and fill again the current_context table: contextDataHandler = function(transaction, results) { try { mydb.transaction( function(transaction) { transaction.executeSql("drop table current_context;", [], nullDataHandler, errorHandler); transaction.executeSql("create table current_context(id String);", [], nullDataHandler, errorHandler); } ) } catch(e) { alert(e.message); } var s = ""; for (var i=0; i < results.rows.length; i++) { var item = results.rows.item(0); s += item['number'] + " "; mydb.transaction( function(tx) { tx.executeSql("insert into current_context(id) values (?);", [item['number']]); } ) } alert(s); } the result is, i get the current_context table deleted, recreated, and filled, but all the rows are filled with the LAST artwork id. the query to retrieve the artworks ids works, so i think it's a transaction problem, but i cant figure out where. thanks for any help

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