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• Not able to access external Hard disk

  - by Jash Jacob

  I have a 1TB External Hard drive which I'm currently not able to access. When I open the External drive in Finder, It shows it's empty. When I use the option to "Get Info", I get the dialog box stating it has about 300GB Free. Tried to get into the External Drive using Terminal, I had no luck. Checking in Disk Utility, It showed that I have many number of files but ZERO folder. I tried to "repair disk", in the process the external Drive got unmounted in between the process. I checked this drive on Windows. I was able to open almost all the folders but I wasn't able to copy anything onto the external drive. One folder caused my windows computer to hang, So i connected the drive back onto my MacBook Pro and tried to access the drive through terminal (this time it worked!) and then I tried to delete the folder with rm command, I got an "input/output error" What should i do to recover the files in that folder? How can i access my external drive on my mac

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• Ubuntu hard disk getting SATA errors

  - by Henadzy

  I am getting "UNC" errors on a hard disk on Ubuntu 9.10. It slows down my system, applications have not been responding for a long time. But when I mount the filesystem on another computer, it works properly. disk: SAMSUNG HD161HJ (SATA) syslog: Apr 25 00:28:25 vare6gin kernel: [ 885.773839] ata3.00: exception Emask 0x1 SAct 0x1e SErr 0x0 action 0x6 frozen Apr 25 00:28:25 vare6gin kernel: [ 885.773845] ata3.00: Ata error. fis:0x21 Apr 25 00:28:25 vare6gin kernel: [ 885.773861] ata3.00: cmd 60/08:08:3f:00:ad/00:00:10:00:00/40 tag 1 ncq 4096 in Apr 25 00:28:25 vare6gin kernel: [ 885.773864] res 51/40:24:67:c8:91/40:00:05:00:00/40 Emask 0x9 (media error) Apr 25 00:28:25 vare6gin kernel: [ 885.773871] ata3.00: status: { DRDY ERR } Apr 25 00:28:25 vare6gin kernel: [ 885.773877] ata3.00: error: { UNC } [...snip 3 similar repeats of last 4 lines; see revision history for full log...] Apr 25 00:28:25 vare6gin kernel: [ 885.773970] ata3: hard resetting link Apr 25 00:28:25 vare6gin kernel: [ 885.773974] ata3: nv: skipping hardreset on occupied port Apr 25 00:28:25 vare6gin kernel: [ 886.240073] ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 300) Apr 25 00:28:25 vare6gin kernel: [ 886.256277] ata3.00: configured for UDMA/133 Apr 25 00:28:25 vare6gin kernel: [ 886.256305] ata3: EH complete Apr 25 00:28:27 vare6gin kernel: [ 888.176088] ata3: EH in SWNCQ mode,QC:qc_active 0xF sactive 0xF Apr 25 00:28:27 vare6gin kernel: [ 888.176099] ata3: SWNCQ:qc_active 0xF defer_bits 0x0 last_issue_tag 0x3 Apr 25 00:28:27 vare6gin kernel: [ 888.176102] dhfis 0xF dmafis 0x1 sdbfis 0x0 Apr 25 00:28:27 vare6gin kernel: [ 888.176109] ata3: ATA_REG 0x51 ERR_REG 0x40 Apr 25 00:28:27 vare6gin kernel: [ 888.176113] ata3: tag : dhfis dmafis sdbfis sacitve Apr 25 00:28:27 vare6gin kernel: [ 888.176120] ata3: tag 0x0: 1 1 0 1 Apr 25 00:28:27 vare6gin kernel: [ 888.176126] ata3: tag 0x1: 1 0 0 1 Apr 25 00:28:27 vare6gin kernel: [ 888.176131] ata3: tag 0x2: 1 0 0 1 Apr 25 00:28:27 vare6gin kernel: [ 888.176136] ata3: tag 0x3: 1 0 0 1

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• MySQL getting stuck, eating up disk i/o

  - by bonez05

  Hi all, Using mySQL 5.0.51 on Solaris . At intermittent times it looks like MySQL is getting 'stuck' . The disk usage on the server spikes to 98% busy from reads. I used dtrace (specifically DTrace toolkit - iosnoop) to track down what processes was using all the reads. Mysql was calling tablename.TDM hundreds of times per second. There was no more than average load on the webserver that could account for this. There were no cronjobs running, and no other utilities like mysqldump or anything. It is a master / slave replication setup. As a jury-rigged fix, I altered the mysql table from 'tablename' to 'tablename2' and then back to 'tablename' This fixed the problem temporarily, and "unsticks" mysql. The disk usage goes back down and dtrace is no longer showing hundreds of reads to 'tablename.TDM' / second. A couple ideas I had are: 1. MySQL version bug 2. Infinite loop somewhere in my application (which i'm not sure how likely this is) 3. ?? Has anybody seen this before or have any insight? Thanks

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• grub2 error : out of disk

  - by Nostradamnit

  Hi everyone, I recently install ArchBang on a machine with Ubuntu and XP. I ran update-grub from Ubuntu and it found the new install and created an entry. However, when I try to boot it, I get: error: out of disk error: you need to load kernel first I've tried several things, including adding a new entry in 40_custom, but nothing changes. Here are the entries I have: default found by update-grub ### BEGIN /etc/grub.d/30_os-prober ### menuentry "ArchBang Linux (on /dev/sda4)" { insmod part_msdos insmod ext2 set root='(hd0,msdos4)' search --no-floppy --fs-uuid --set 75f96b44-3a8f-4727-9959-d669b9244f2a linux /boot/vmlinuz26 root=/dev/sda4 rootfstype=ext4 ro xorg=vesa quiet nomodeset swapon initrd /boot/kernel26.img } menuentry "ArchBang Linux Fallback (on /dev/sda4)" { insmod part_msdos insmod ext2 set root='(hd0,msdos4)' search --no-floppy --fs-uuid --set 75f96b44-3a8f-4727-9959-d669b9244f2a linux /boot/vmlinuz26 root=/dev/sda4 rootfstype=ext4 ro xorg=vesa quiet nomodeset swapon initrd /boot/kernel26-fallback.img } ### END /etc/grub.d/30_os-prober ### custom entry in 40_custom based on various ideas found on the internets menuentry "ArchBang Linux (on /dev/sda4)" { insmod part_msdos insmod ext2 set root='(hd0,msdos4)' search --no-floppy --fs-uuid --set 75f96b44-3a8f-4727-9959-d669b9244f2a linux /boot/vmlinuz26 root=/dev/disk/by-uuid/75f96b44-3a8f-4727-9959-d669b9244f2a rootfstype=ext4 ro xorg=vesa quiet nomodeset swapon initrd /boot/kernel26.img } I think the problem has something to do with the sda4 not being mounted at boot-time... Thanks in advance for you help, Sam

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• Recovery disk Windows 8 HP Pavilion g6

  - by fpghost

  I recently purchased a HP Pavilion g6 laptop running Windows 8. I want to either obtain the Windows 8 ISO or make some kind of recovery disk that would allow me to restore the system if things go wrong. The HP Pavilion comes with the 'HP Recovery Manager' which I thought may do the job, but on running it and putting in a DVD-R as requested it seems to just hang for a number of hours without doing a thing (the disk sounds like it's spinning for a few minutes but then goes silent). I then tried 'recdisc.exe' but I get the error System Repair could not be created The device reported unexpected or invalid data for a command. (0xC0AA02FF) Next I obtained my Windows 8 product key using the software ProduKey thinking this would allow me to go to the Microsoft website and download the Windows 8 ISO, but as far as I can tell all that is available is the upgrade which can be used if one is running something like Windows 7. Can anyone advise? EDIT: after a reboot recdisc.exe did work; I think the problem was due to some Windows updates needing a reboot, but never the less I would like a full Windows 8 ISO if possible.

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• p410i Mirror failed couldnt find same disk

  - by Heishiro Mitsurugi

  I have an HP server with an P410i RAID Card installed. I had two SATA Drives connected (250GB each). The RAID was configured as a Mirror. A few days ago the drive one (1) failed, and i had to remove it. Tried to find the same part number here in Venezuela, but i couldn't. So, i bought a 500GB SATA Drive, and connected it to the same bay where the 250GB failed drive was. When the server booted, it asked me if i wanted to rebuild the data. I selected the option for that, and Windows Server restarted properly. When i got into the ACU (Array Configuration Utility) it told me that it was rebuilding the data. Today the warning went away, and according to the ACU everything is just fine. My question is... What i did was right? Can i create a mirror from a 250GB disk in a 500GB disk using the p410i? I have done that before, but only using software RAID in Windows, and it just uses the space it needs. As a matter of fact, when did that using Windows i was able to use the remaining space in the bigger drive, but in the p410i i can't use it. Should i be worried? Thanks a lot in advance for any pointers or info that you could give on this. Heishiro

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• Performance of external USB disk with ESXi5

  - by PeterMmm

  I have a new HP DL120 G7 server with ESXi5. One VM is a Win2003 instalation and I have an external USB2.0 drive attached by USB Controller and USB Device. I copy a 4GB file from external USB to server disk. In the VM that takes up to 10 minutes. On a native Win2003 that takes aprox. 3 minutes. I have no explaination for that diference: In any case the bottleneck is the USB connection, much slower than the disks (SAS, RAID1). If the USB connection on the VM would be USB1.1 and not USB2.0 it would take much more time. (The disk performance between server partitions on the VM is correct. - see update) Could be that my native box is extremely fast and the VM is the normal case. ??? Update I try with passtrough and a first run copy the same data in aprox. 7 minutes. Still 2 times slower than the native connection. I also did another messure and the copy between partitions on the same VM takes 3 minutes.

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• Build and migrated to software raid (mdadm) on GPT disk, now can't assemble array

  - by John H

  mdadm, gpt issues, unrecognized partitions. Simplified question: How do I get mdadm to recognize GPT partitions? I have been attempting to convert/copy my Ubuntu 11.10 OS from a single drive to software raid 1. I have done similar in the past, but in this case, I was adding in a drive that has been configured for GPT and I tried to work with that without fully looking into the implications. Currently, I have a non-booting mdadm RAID 1 array of /dev/md127 (the OS assigned that and it keeps picking up). I am booting off of live USB keys, currently System Rescue CD from sysresccd. While gdisk and parted can see all the partitions, most of the OS utilities do not, including mdadm. My main goal is just to make the raid array accessible so I can get pull the data and start fresh (without using GPT). /dev/md127 /dev/sda /dev/sda1 <- GPT type partition /dev/sda1 <- exists within the GPT part, member of md127 /dev/sda2 <- exists within the GPT part, empty /dev/sdb /dev/sdb1 <- GPT type partition /dev/sdb1 <- exists within the GPT part, member of md127 History: POINT A: The original OS was install on sda (actually /dev/sda6). I used a the Ubuntu live usb to add sdb. I got warning from fdisk about GPT so I used gdisk to create a raid partition (sdb1) and mdadm to create a raid1 mirror with a missing drive. I had many issues getting this working (including being unable to get grub to install) but I eventually got it to boot using grub on sda and /dev/md127 off of sdb. So at point A, I had copied my OS from sda6 to md127 on sdb. I then booted into a rescue mode and attempted to get a bootloader onto sdb, which failed. I then discovered my mistake: I had installed the raid onto sdb instead of sdb1, essentially overwriting the sdb1 partition. POINT B: I now had two copies of my data- one on md127/sdb, and one on sda. I destroyed data on sda and created a new GPT table on sda. I then created sda1 for the raid array, and sda2 for a scratch partition. I added sda1 into the raid array and let it rebuild. md127 now covered /dev/sdb and /dev/sda1 as fully active and synced. POINT C: I rebooted onto linux rescue again and was still able to access the raid array. I then removed /dev/sdb from the array and created /dev/sdb1 for the raid. I added sdb1 to the array and let it sync. I was able to mount and access /dev/md127 without issues. Once it completed, both /dev/sda1 and /dev/sdb1 were GPT partitions and actively syncing. POINT D (current): I rebooted again to test if the array would boot and grub failed to load. I booted off of my live thumb drive and found that I can no longer assemble the raid array. mdadm doesn't see the required partitions. -- root@freshdesk /root % uname -a Linux freshdesk 3.0.24-std251-amd64 #2 SMP Sat Mar 17 12:08:55 UTC 2012 x86_64 AMD Athlon(tm) II X4 645 Processor AuthenticAMD GNU/Linux === /proc/partitions and parted look good: root@freshdesk /root % cat /proc/partitions major minor #blocks name 7 0 301788 loop0 8 0 976762584 sda 8 1 732579840 sda1 8 2 244181703 sda2 8 16 732574584 sdb 8 17 732573543 sdb1 8 32 7876607 sdc 8 33 7873349 sdc1 (parted) print all Model: ATA ST31000528AS (scsi) Disk /dev/sda: 1000GB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name Flags 1 1049kB 750GB 750GB ext4 2 750GB 1000GB 250GB Linux/Windows data Model: ATA SAMSUNG HD753LJ (scsi) Disk /dev/sdb: 750GB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name Flags 1 1049kB 750GB 750GB ext4 Linux RAID raid Model: SanDisk SanDisk Cruzer (scsi) Disk /dev/sdc: 8066MB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 31.7kB 8062MB 8062MB primary fat32 boot, lba === # no sda2, and I double the sdb1 is the one shown in parted root@freshdesk /root % blkid /dev/loop0: TYPE="squashfs" /dev/sda1: UUID="75dd6c2d-f0a8-4302-9da4-792cc7d72355" TYPE="ext4" /dev/sdc1: LABEL="PENDRIVE" UUID="1102-3720" TYPE="vfat" /dev/sdb1: UUID="2dd89f15-65bb-ff88-e368-bf24bd0fce41" TYPE="linux_raid_member" root@freshdesk /root % mdadm -E /dev/sda1 mdadm: No md superblock detected on /dev/sda1. # this is probably a result of me attempting to force the array up, putting superblocks on the GPT partition root@freshdesk /root % mdadm -E /dev/sdb1 /dev/sdb1: Magic : a92b4efc Version : 0.90.00 UUID : 2dd89f15:65bbff88:e368bf24:bd0fce41 Creation Time : Fri Mar 30 19:25:30 2012 Raid Level : raid1 Used Dev Size : 732568320 (698.63 GiB 750.15 GB) Array Size : 732568320 (698.63 GiB 750.15 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 127 Update Time : Sat Mar 31 12:39:38 2012 State : clean Active Devices : 1 Working Devices : 2 Failed Devices : 1 Spare Devices : 1 Checksum : a7d038b3 - correct Events : 20195 Number Major Minor RaidDevice State this 2 8 17 2 spare /dev/sdb1 0 0 8 1 0 active sync /dev/sda1 1 1 0 0 1 faulty removed 2 2 8 17 2 spare /dev/sdb1 === root@freshdesk /root % mdadm -A /dev/md127 /dev/sda1 /dev/sdb1 mdadm: no recogniseable superblock on /dev/sda1 mdadm: /dev/sda1 has no superblock - assembly aborted root@freshdesk /root % mdadm -A /dev/md127 /dev/sdb1 mdadm: cannot open device /dev/sdb1: Device or resource busy mdadm: /dev/sdb1 has no superblock - assembly aborted

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• SQL SERVER – Four Posts on Removing the Bookmark Lookup – Key Lookup

  - by pinaldave

  In recent times I have observed that not many people have proper understanding of what is bookmark lookup or key lookup. Increasing numbers of the questions tells me that this is something developers are encountering every single day but have no idea how to deal with it. I have previously written three articles on this subject. I want to point all of you looking for further information on the same post. SQL SERVER – Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup SQL SERVER – Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup – Part 2 SQL SERVER – Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup – Part 3 SQL SERVER – Interesting Observation – Execution Plan and Results of Aggregate Concatenation Queries In one of my recent class we had in depth conversation about what are the alternative of creating covering indexes to remove the bookmark lookup. I really want to this question open to all of you and see what community thinks about the same. Is there any other way then creating covering index or included index to remove his expensive keylookup? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Backup and Restore, SQL Index, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLAuthority News, SQLServer, T SQL, Technology

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• SQL SERVER – Subquery or Join – Various Options – SQL Server Engine Knows the Best – Part 2

  - by pinaldave

  This blog post is part 2 of the earlier written article SQL SERVER – Subquery or Join – Various Options – SQL Server Engine knows the Best by Paulo R. Pereira. Paulo has left excellent comment to earlier article once again proving the point that SQL Server Engine is smart enough to figure out the best plan itself and uses the same for the query. Let us go over his comment as he has posted. “I think IN or EXISTS is the best choice, because there is a little difference between ‘Merge Join’ of query with JOIN (Inner Join) and the others options (Left Semi Join), and JOIN can give more results than IN or EXISTS if the relationship is 1:0..N and not 1:0..1. And if I try use NOT IN and NOT EXISTS the query plan is different from LEFT JOIN too (Left Anti Semi Join vs. Left Outer Join + Filter). So, I found a case where EXISTS has a different query plan than IN or ANY/SOME:” USE AdventureWorks GO -- use of SOME SELECT * FROM HumanResources.Employee E WHERE E.EmployeeID = SOME ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA UNION ALL SELECT EA.EmployeeID FROM HumanResources.EmployeeDepartmentHistory EA ) -- use of IN SELECT * FROM HumanResources.Employee E WHERE E.EmployeeID IN ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA UNION ALL SELECT EA.EmployeeID FROM HumanResources.EmployeeDepartmentHistory EA ) -- use of EXISTS SELECT * FROM HumanResources.Employee E WHERE EXISTS ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA UNION ALL SELECT EA.EmployeeID FROM HumanResources.EmployeeDepartmentHistory EA ) When looked into execution plan of the queries listed above indeed we do get different plans for queries and SQL Server Engines creates the best (least cost) plan for each query. Click on image to see larger images. Thanks Paulo for your wonderful contribution. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, Readers Contribution, SQL, SQL Authority, SQL Joins, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Fastest Way to Restore the Database

  - by pinaldave

  A few days ago, I received following email: “Pinal, We are in an emergency situation. We have a large database of around 80+ GB and its backup is of 50+ GB in size. We need to restore this database ASAP and use it; however, restoring the database takes forever. Do you think a compressed backup would solve our problem? Any other ideas you got?” First of all, the asker has already answered his own question. Yes; I have seen that if you are using a compressed backup, it takes lesser time when you try to restore a database. I have previously blogged about the same subject. Here are the links to those blog posts: SQL SERVER – Data and Page Compressions – Data Storage and IO Improvement SQL SERVER – 2008 – Introduction to Row Compression SQL SERVER – 2008 – Introduction to New Feature of Backup Compression However, if your database is very large that it still takes a few minutes to restore the database even though you use any of the features listed above, then it will really take some time to restore the database. If there is urgency and there is no time you can spare for restoring the database, then you can use the wonderful tool developed by Idera called virtual database. This tool restores a certain database in just a few seconds so it will readily be available for usage. I have in depth written my experience with this tool in the article here SQL SERVER – Retrieve and Explore Database Backup without Restoring Database – Idera virtual database. Let me know your experience in this scenario. Have you ever needed your database backup restored very quickly, what did you do in that scenario. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, Readers Question, SQL, SQL Authority, SQL Backup and Restore, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• OBIEE 11.1.1 - Disable Wrap Data Types in WebLogic Server 10.3.x

  - by Ahmed Awan

  By default, JDBC data type’s objects are wrapped with a WebLogic wrapper. This allows for features like debugging output and track connection usage to be done by the server. The wrapping can be turned off by setting this value to false. This improves performance, in some cases significantly, and allows for the application to use the native driver objects directly. Tip: How to Disable Wrapping in WLS Administration Console You can use the Administration Console to disable data type wrapping for following JDBC data sources in bifoundation_domain domain: Data Source Name bip_datasource mds-owsm EPMSystemRegistry   To disable wrapping for each JDBC data source (as stated in above table): 1.     If you have not already done so, in the Change Center of the Administration Console, click Lock & Edit. 2.     In the Domain Structure tree, expand Services, then select Data Sources. 3.     On the Summary of Data Sources page, click the data source name for example “mds-owsm”. 4.     Select the Configuration: Connection Pool tab. 5.     Scroll down and click Advanced to show the advanced connection pool options. 6.     In Wrap Data Types, deselect the checkbox to disable wrapping. 7.     Click Save. 8.     To activate these changes, in the Change Center of the Administration Console, click Activate Changes. Important Note: This change does not take effect immediately—it requires the server be restarted.

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• SQL SERVER – Find Most Expensive Queries Using DMV

  - by pinaldave

  The title of this post is what I can express here for this quick blog post. I was asked in recent query tuning consultation project, if I can share my script which I use to figure out which is the most expensive queries are running on SQL Server. This script is very basic and very simple, there are many different versions are available online. This basic script does do the job which I expect to do – find out the most expensive queries on SQL Server Box. SELECT TOP 10 SUBSTRING(qt.TEXT, (qs.statement_start_offset/2)+1, ((CASE qs.statement_end_offset WHEN -1 THEN DATALENGTH(qt.TEXT) ELSE qs.statement_end_offset END - qs.statement_start_offset)/2)+1), qs.execution_count, qs.total_logical_reads, qs.last_logical_reads, qs.total_logical_writes, qs.last_logical_writes, qs.total_worker_time, qs.last_worker_time, qs.total_elapsed_time/1000000 total_elapsed_time_in_S, qs.last_elapsed_time/1000000 last_elapsed_time_in_S, qs.last_execution_time, qp.query_plan FROM sys.dm_exec_query_stats qs CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) qt CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) qp ORDER BY qs.total_logical_reads DESC -- logical reads -- ORDER BY qs.total_logical_writes DESC -- logical writes -- ORDER BY qs.total_worker_time DESC -- CPU time You can change the ORDER BY clause to order this table with different parameters. I invite my reader to share their scripts. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLAuthority News, SQLServer, T SQL, Technology Tagged: SQL DMV

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• SQLAuthority News – 18 Seconds of Fame – My PASS Experience

  - by pinaldave

  Happy Holidays to All of YOU! Life is full of little and happy surprises. I think Christmas and Santa are based on it. I just received very interesting email earlier today, I had no idea about it. Earlier this year, I had visited Seattle to attend SQLPASS – read the complete summary over here: SQLAuthority News – SQLPASS Nov 8-11, 2010-Seattle – An Alternative Look at Experience. While I was walking down, someone has stopped me and asked if they can talk to me for 15 seconds, I said yes and they had shot quick movie with mobile. The conversation was very quick and I had forgotten about it. Today I received email from one of the blog reader about it being on YouTube. Honestly, I did not know if this was ever going to be on YouTube. I am surprised and thrilled. Watch my 18 seconds fame movie. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: About Me, Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, T SQL, Technology

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• Starting a Java activity in Unity3d Android

  - by Matthew Pavlinsky

  I wrote a small Java activity extension of UnityPlayerActivity similar to what is described in the Unity docs. It has a method for displaying a song picking interface using an ACTION_GET_CONTENT intent. I start this activity using startActivityForResult() and it absolutely kills the performance of my Unity game when it is finished, it drops to about .1 FPS afterwords. I've changed removed the onActivityResult function and even tried starting the activity from inside an onKeyDown event in Java to make sure my method of starting the activity from Unity was not the problem. Heres the code in a basic sense: package com.company.product; import com.unity3d.player.UnityPlayerActivity; import com.unity3d.player.UnityPlayer; import android.os.Bundle; import android.util.Log; import android.content.Intent; public class SongPickerActivity extends UnityPlayerActivity { private Intent myIntent; final static int PICK_SONG = 1; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Log.i("SongPickerActivity", "OnCreate"); myIntent = new Intent(Intent.ACTION_GET_CONTENT); myIntent.setType("audio/*"); } public void Pick() { Log.i("SongPickerActivity", "Pick"); startActivityForResult(myIntent, PICK_SONG); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); } } This is causing me a bit more of a headache than it should and I would be thankful for any sort of advice. Does anyone have any experience with using custom activities in Unity Android or any insight on why this is happening or how to resolve this?

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• Python — Time complexity of built-in functions versus manually-built functions in finite fields

  - by stackuser

  Generally, I'm wondering about the advantages versus disadvantages of using the built-in arithmetic functions versus rolling your own in Python. Specifically, I'm taking in GF(2) finite field polynomials in string format, converting to base 2 values, performing arithmetic, then output back into polynomials as string format. So a small example of this is in multiplication: Rolling my own: def multiply(a,b): bitsa = reversed("{0:b}".format(a)) g = [(b<<i)*int(bit) for i,bit in enumerate(bitsa)] return reduce(lambda x,y: x+y,g) Versus the built-in: def multiply(a,b): # a,b are GF(2) polynomials in binary form .... return a*b #returns product of 2 polynomials in gf2 Currently, operations like multiplicative inverse (with for example 20 bit exponents) take a long time to run in my program as it's using all of Python's built-in mathematical operations like // floor division and % modulus, etc. as opposed to making my own division, remainder, etc. I'm wondering how much of a gain in efficiency and performance I can get by building these manually (as shown above). I realize the gains are dependent on how well the manual versions are built, that's not the question. I'd like to find out 'basically' how much advantage there is over the built-in's. So for instance, if multiplication (as in the example above) is well-suited for base 10 (decimal) arithmetic but has to jump through more hoops to change bases to binary and then even more hoops in operating (so it's lower efficiency), that's what I'm wondering. Like, I'm wondering if it's possible to bring the time down significantly by building them myself in ways that maybe some professionals here have already come across.

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• SQL SERVER – Plan Cache and Data Cache in Memory

  - by pinaldave

  I get following question almost all the time when I go for consultations or training. I often end up providing the scripts to my clients and attendees. Instead of writing new blog post, today in this single blog post, I am going to cover both the script and going to link to original blog posts where I have mentioned about this blog post. Plan Cache in Memory USE AdventureWorks GO SELECT [text], cp.size_in_bytes, plan_handle FROM sys.dm_exec_cached_plans AS cp CROSS APPLY sys.dm_exec_sql_text(plan_handle) WHERE cp.cacheobjtype = N'Compiled Plan' ORDER BY cp.size_in_bytes DESC GO Further explanation of this script is over here: SQL SERVER – Plan Cache – Retrieve and Remove – A Simple Script Data Cache in Memory USE AdventureWorks GO SELECT COUNT(*) AS cached_pages_count, name AS BaseTableName, IndexName, IndexTypeDesc FROM sys.dm_os_buffer_descriptors AS bd INNER JOIN ( SELECT s_obj.name, s_obj.index_id, s_obj.allocation_unit_id, s_obj.OBJECT_ID, i.name IndexName, i.type_desc IndexTypeDesc FROM ( SELECT OBJECT_NAME(OBJECT_ID) AS name, index_id ,allocation_unit_id, OBJECT_ID FROM sys.allocation_units AS au INNER JOIN sys.partitions AS p ON au.container_id = p.hobt_id AND (au.TYPE = 1 OR au.TYPE = 3) UNION ALL SELECT OBJECT_NAME(OBJECT_ID) AS name, index_id, allocation_unit_id, OBJECT_ID FROM sys.allocation_units AS au INNER JOIN sys.partitions AS p ON au.container_id = p.partition_id AND au.TYPE = 2 ) AS s_obj LEFT JOIN sys.indexes i ON i.index_id = s_obj.index_id AND i.OBJECT_ID = s_obj.OBJECT_ID ) AS obj ON bd.allocation_unit_id = obj.allocation_unit_id WHERE database_id = DB_ID() GROUP BY name, index_id, IndexName, IndexTypeDesc ORDER BY cached_pages_count DESC; GO Further explanation of this script is over here: SQL SERVER – Get Query Plan Along with Query Text and Execution Count Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL Tagged: SQL Memory

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• Is 1GB RAM with integrated graphics sufficient for Unity 3D on 12.04?

  - by Anwar Shah

  I have been using Ubuntu since Hardy Heron (8.04). I used Natty, Oneiric with Unity. But When I recently (more than 1 month now) upgraded My Ubuntu to Precise (12.04), the performance of my laptop is not satisfactory. It is too unresponsive compared to older releases. For example, the Unity in 12.04 is very unresponsive. Sometimes, it requires 2 seconds to show up the dash (which was not the case with Natty, though people always saying that Natty's version of Unity is buggiest). I am assuming that, May be my 1GB RAM now becomes too low to run Unity of Precise. But I also think, Since Unity is improved in Precise, It may not be the case. So, I am not sure. Do you have any ideas? Will upgrading RAM fix it? How much I need if upgrade is required? Laptop model: "Lenovo 3000 Y410" Graphic : "Intel GMA X3100" on Intel 965GM Chipset. RAM/Memory : "1 GB DDR2" (1 slot empty). Swap space : 1.1GB Resolution: 1280x800 widescreen Shared RAM for Graphics: 256 MB as below output suggests $ dmesg | grep AGP [ 0.825548] agpgart-intel 0000:00:00.0: AGP aperture is 256M @ 0xd0000000

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• Slower site with the *same* configuration than a mirror copy…?

  - by Rosamunda Rosamunda

  I´ve got this Drupal site (ligadelconsorcista.org) that I have to move it from one server to another. The reason was that my older host even when it was pretty decent, it started a couple of months now to have many short downtimes, wich drove me crazy. The thing is that I´ve made a sort of mirror copy of the site: I´ve copied all the files exactly the same, and after that I´ve imported the database. The problem is that the new site connects much slower than my old hosting! (the new one is mediatemple) I´ve contacted their support and they tell me that there are several factors that can contribute to that... but that has nothing to do with their hosting service. The thing is that I don´t even know where to start looking for the problem. Notes: The new configuration is the same that the one I had with the older hosting account. Today I´ve set an account with cloudflare´s CDN to try to solve the problem. Even if the CDN is configured ok (I´ve asked their help desk) it won´t add any performance improvement. Any clues of what may I do about this? Thanks!!

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• Munq is for web, Unity is for Enterprise

  - by oazabir

  The Unity Application Block (Unity) is a lightweight extensible dependency injection container with support for constructor, property, and method call injection. It’s a great library for facilitating Inversion of Control and the recent version supports AOP as well. However, when it comes to performance, it’s CPU hungry. In fact it’s so CPU hungry that it makes it impossible to make it work at Internet Scale. I was investigating some CPU issue on a portal that gets around 3MM hits per day and I found unusually high CPU. Here’s why: I did some CPU profiling on my open source project Dropthings and found that the highest CPU is consumed by Unity’s Resolve<>(). There’s no funky use of Unity in the project. Straightforward Register<>() and Resolve<>(). But as you can see, Resolve<>() is consuming significantly high CPU even after the site is warm and has been running for a while. Then I tried Munq, which is a basic Dependency Injection Container. It has everything you will usually need in a regular project. It boasts to be the fastest DI out there. So, I converted all Unity code to Munq in Dropthings and did a CPU profile and Whala!   There’s no trace of any Munq calls anywhere. That proves Munq is a lot faster than Unity.

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• Out of space despite lots of free space remaining

  - by Kristian Thomsen

  When upgrading Ubuntu from 11.10 to 12.04 I discovered an unexpected problem. The upgrade was stopped because there wasn't enough free space for the installation. I managed to free some space and do the upgrade but now a prompt appears after logging in saying I'm out of space. This prompt asks me if I want to examine the problem. The "Disk Usage Analyser" is opened. In the top it says: Total filesystem capacity: 47.0 GB (used: 13.5 GB available: 33.4 GB) Folder -- Usage -- Size / -- 100% -- 12.5 GB usr -- 44.8 % -- 5.6 GB home -- 30.3 % -- 3.8 GB lib -- 13.0 % -- 1.6 GB var -- 9.1 % -- 1.1 GB boot 2.5 % 309.5 GB and a lot of small contributors like: etc, opt, sbin, bin etc. I do not really understand this problem since the analyser in the top says that I have 33.4 GB left in this file system. What can I do to make Ubuntu use the remaining space? Running df -i in the terminal gives: Filesystem Inodes IUsed IFree IUse% Mounted on /dev/sda7 610800 576874 33926 95% / udev 213451 563 212888 1% /dev tmpfs 218524 486 218038 1% /run none 218524 3 218521 1% /run/lock none 218524 7 218517 1% /run/shm /dev/sda8 2264752 16371 2248381 1% /home What does this mean?

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• Caching WCF javascript proxy on browser

  - by oazabir

  When you use WCF services from Javascript, you have to generate the Javascript proxies by hitting the Service.svc/js. If you have five WCF services, then it means five javascripts to download. As browsers download javascripts synchronously, one after another, it adds latency to page load and slows down page rendering performance. Moreover, the same WCF service proxy is downloaded from every page, because the generated javascript file is not cached on browser. Here is a solution that will ensure the generated Javascript proxies are cached on browser and when there is a hit on the service, it will respond with HTTP 304 if the Service.svc file has not changed. Here’s a Fiddler trace of a page that uses two WCF services. You can see there are two /js hits and they are sequential. Every visit to the same page, even with the same browser session results in making those two hits to /js. Second time when the same page is browsed: You can see everything else is cached, except the WCF javascript proxies. They are never cached because the WCF javascript proxy generator does not produce the necessary caching headers to cache the files on browser. Here’s an HttpModule for IIS and IIS Express which will intercept calls to WCF service proxy. It first checks if the service is changed since the cached version on the browser. If it has not changed then it will return HTTP 304 and not go through the service proxy generation process. Thus it saves some CPU on server. But if the request is for the first time and there’s no cached copy on browser, it will deliver the proxy and also emit the proper cache headers to cache the response on browser. http://www.codeproject.com/Articles/360437/Caching-WCF-javascript-proxy-on-browser Don’t forget to vote.

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• Where is a good place to start to learn about custom caching in .Net

  - by John

  I'm looking to make some performance enhancements to our site, but I'm not sure exactly where to begin. We have some custom object caching, but I think that we can do better. Our Business We aggregate news stories on a news type of web site. We get approximately 500-1000 new stories per week. We have index pages that show various lists of the items and details pages that show the individual stories. Our Current Use case: Getting an Individual Story User makes a request The Data Access Layer(DAL) checks to see if the item is in cache and if item is fresh (15 minutes). If the item is not in cache or is not fresh, retrieve the item from SQL Server, save to cache and return to user. Problems with this approach The pull nature of caching means that users have to pay the waiting cost every time that the cache is refreshed. Once a story is published, it changes infrequently and I think that we should replace the pull model with something better. My initial thoughts My initial thought is that stories should ALL be stored locally in some type of dictionary. (Cache or is there another, better way?). If the story is not found, then make a trip to the database, update the local dictionary and send the item back. Since there may be occasional updates to stories, this should be an entirely process from the user. I watched a video by Brent Ozar, How StackOverflow Scales SQL Server, in which Brent states "the fastest database query is the one that you don't make". Where do I start? At this point, I don't know exactly what the solution is. Is it caching? Is there a better way of using local storage? Do I use a Dictionary, OrderedDictionary, List ? It seems daunting and I'm just looking for some good starting points to learn more about how to do this type of optimization.

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• Perfomance of 8 bit operations on 64 bit architechture

  - by wobbily_col

  I am usually a Python / Database programmer, and I am considering using C for a problem. I have a set of sequences, 8 characters long with 4 possible characters. My problem involves combining sets of these sequences and filtering which sets match a criteria. The combinations of 5 run into billions of rows and takes around an hour to run. So I can represent each sequence as 2 bytes. If I am working on a 64 bit architechture will I gain any advantage by keeping these data structures as 2 bytes when I generate the combinations, or will I be as well storing them as 8 bytes / double ? (64 bit = 8 x 8) If I am on a 64 bit architecture, all registers will be 64 bit, so in terms of operations that shouldn´t be any faster (please correct me if I am wrong). Will I gain anything from the smaller storage requirements - can I fit more combinations in memory, or will they all take up 64 bits anyway? And finally, am I likley to gain anything coding in C. I have a first version, which stores the sequence as a small int in a MySQL database. It then self joins the tabe to itself a number of times in order to generate all the possible combinations. The performance is acceptable, depending on how many combinations are generated. I assume the database must involve some overhead.

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• Is there a better way to consume an ASP.NET Web API call in an MVC controller?

  - by davidisawesome

  In a new project I am creating for my work I am creating a fairly large ASP.NET Web API. The api will be in a separate visual studio solution that also contains all of my business logic and database interactions, Model classes as well. In the test application I am creating (which is asp.net mvc4), I want to be able to hit an api url I defined from the control and cast the return JSON to a Model class. The reason behind this is that I want to take advantage of strongly typing my views to a Model. This is all still in a proof of concept stage, so I have not done any performance testing on it, but I am curious if what I am doing is a good practice, or if I am crazy for even going down this route. Here is the code on the client controller: public class HomeController : Controller { protected string dashboardUrlBase = "http://localhost/webapi/api/StudentDashboard/"; public ActionResult Index() //This view is strongly typed against User { //testing against Joe Bob string adSAMName = "jBob"; WebClient client = new WebClient(); string url = dashboardUrlBase + "GetUserRecord?userName=" + adSAMName; //'User' is a Model class that I have defined. User result = JsonConvert.DeserializeObject<User>(client.DownloadString(url)); return View(result); } . . . } If I choose to go this route another thing to note is I am loading several partial views in this page (as I will also do in subsequent pages). The partial views are loaded via an $.ajax call that hits this controller and does basically the same thing as the code above: Instantiate a new WebClient Define the Url to hit Deserialize the result and cast it to a Model Class. So it is possible (and likely) I could be performing the same actions 4-5 times for a single page. Is there a better method to do this that will: Let me keep strongly typed views. Do my work on the server rather than on the client (this is just a preference since I can write C# faster than I can write javascript).

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