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  • Determining cause of high NFS/IO utilization without iotop

    - by Matt
    I have a server that is doing an NFSv4 export for user's home directories. There are roughly 25 users (mostly developers/analysts) and about 40 servers mounting the home directory export. Performance is miserable, with users often seeing multi-second lags for simple commands (like ls, or writing a small text file). Sometimes the home directory mount completely hangs for minutes, with users getting "permission denied" errors. The hardware is a Dell R510 with dual E5620 CPUs and 8 GB RAM. There are eight 15k 2.5” 600 GB drives (Seagate ST3600057SS) configured in hardware RAID-6 with a single hot spare. RAID controller is a Dell PERC H700 w/512MB cache (Linux sees this as a LSI MegaSAS 9260). OS is CentOS 5.6, home directory partition is ext3, with options “rw,data=journal,usrquota”. I have the HW RAID configured to present two virtual disks to the OS: /dev/sda for the OS (boot, root and swap partitions), and /dev/sdb for the home directories. What I find curious, and suspicious, is that the sda device often has very high utilization, even though it only contains the OS. I would expect this virtual drive to be idle almost all the time. The system is not swapping, according to "free" and "vmstat". Why would there be major load on this device? Here is a 30-second snapshot from iostat: Time: 09:37:28 AM Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0.00 44.09 0.03 107.76 0.13 607.40 11.27 0.89 8.27 7.27 78.35 sda1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 sda2 0.00 44.09 0.03 107.76 0.13 607.40 11.27 0.89 8.27 7.27 78.35 sdb 0.00 2616.53 0.67 157.88 2.80 11098.83 140.04 8.57 54.08 4.21 66.68 sdb1 0.00 2616.53 0.67 157.88 2.80 11098.83 140.04 8.57 54.08 4.21 66.68 dm-0 0.00 0.00 0.03 151.82 0.13 607.26 8.00 1.25 8.23 5.16 78.35 dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 dm-2 0.00 0.00 0.67 2774.84 2.80 11099.37 8.00 474.30 170.89 0.24 66.84 dm-3 0.00 0.00 0.67 2774.84 2.80 11099.37 8.00 474.30 170.89 0.24 66.84 Looks like iotop is the ideal tool to use to sniff out these kinds of issues. But I'm on CentOS 5.6, which doesn't have a new enough kernel to support that program. I looked at Determining which process is causing heavy disk I/O?, and besides iotop, one of the suggestions said to do a "echo 1 /proc/sys/vm/block_dump". I did that (after directing kernel messages to tempfs). In about 13 minutes I had about 700k reads or writes, roughly half from kjournald and the other half from nfsd: # egrep " kernel: .*(READ|WRITE)" messages | wc -l 768439 # egrep " kernel: kjournald.*(READ|WRITE)" messages | wc -l 403615 # egrep " kernel: nfsd.*(READ|WRITE)" messages | wc -l 314028 For what it's worth, for the last hour, utilization has constantly been over 90% for the home directory drive. My 30-second iostat keeps showing output like this: Time: 09:36:30 PM Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0.00 6.46 0.20 11.33 0.80 71.71 12.58 0.24 20.53 14.37 16.56 sda1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 sda2 0.00 6.46 0.20 11.33 0.80 71.71 12.58 0.24 20.53 14.37 16.56 sdb 137.29 7.00 549.92 3.80 22817.19 43.19 82.57 3.02 5.45 1.74 96.32 sdb1 137.29 7.00 549.92 3.80 22817.19 43.19 82.57 3.02 5.45 1.74 96.32 dm-0 0.00 0.00 0.20 17.76 0.80 71.04 8.00 0.38 21.21 9.22 16.57 dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 dm-2 0.00 0.00 687.47 10.80 22817.19 43.19 65.48 4.62 6.61 1.43 99.81 dm-3 0.00 0.00 687.47 10.80 22817.19 43.19 65.48 4.62 6.61 1.43 99.82

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  • Disk operations freeze Debian

    - by Grzenio
    Hi, I have just installed Debian testing on my new desktop and I am not very happy with performance - when I perform a disk intensive operation, e.g. upgrade packages in the system, everything seems to freeze, e.g. changing tabs in Iceweasel takes 3 seconds. I run the Debian on my 3 year old Thinkpad X60 ultra-portable, and I don't have these issues. (every single parameter of the laptop is much worse than the desktop). I am using the default packaged kernel and scripts. I run hdparm -t /dev/sda1 And I got around 96GB/s, which is expected. What else can I try to make it work better? EDIT: grzes:/home/ga# hdparm -i /dev/sda /dev/sda: Model=WDC WD15EARS-00Z5B1, FwRev=80.00A80, SerialNo=WD-WMAVU1362357 Config={ HardSect NotMFM HdSw>15uSec SpinMotCtl Fixed DTR>5Mbs FmtGapReq } RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=50 BuffType=unknown, BuffSize=unknown, MaxMultSect=16, MultSect=16 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=2930277168 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120} PIO modes: pio0 pio3 pio4 DMA modes: mdma0 mdma1 mdma2 UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6 AdvancedPM=no WriteCache=enabled Drive conforms to: Unspecified: ATA/ATAPI-1,2,3,4,5,6,7 * signifies the current active mode EDIT2: Even my wife said "on this new computer I can't do anything when I copy the photos from the camera and its much worse than on the old one". So it must be serious. EDIT3: Updated to 2.6.32, but still no improvement EDIT4: I forgot to mention that the new disk is ext4, the old was ext3. EDIT5: Still not solved. I have a P43 ASUS P5QL-E board. Lines from dmesg that seem relevant: [ 0.370850] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 253) [ 0.370852] io scheduler noop registered [ 0.370853] io scheduler anticipatory registered [ 0.370854] io scheduler deadline registered [ 0.370876] io scheduler cfq registered (default) ... [ 0.908233] ata_piix 0000:00:1f.2: version 2.13 [ 0.908243] ata_piix 0000:00:1f.2: PCI INT B -> GSI 19 (level, low) -> IRQ 19 [ 0.908246] ata_piix 0000:00:1f.2: MAP [ P0 P2 P1 P3 ] [ 0.908275] ata_piix 0000:00:1f.2: setting latency timer to 64 [ 0.908316] scsi0 : ata_piix [ 0.908374] scsi1 : ata_piix [ 0.909180] ata1: SATA max UDMA/133 cmd 0xa000 ctl 0x9c00 bmdma 0x9480 irq 19 [ 0.909183] ata2: SATA max UDMA/133 cmd 0x9880 ctl 0x9800 bmdma 0x9488 irq 19 [ 0.909199] ata_piix 0000:00:1f.5: PCI INT B -> GSI 19 (level, low) -> IRQ 19 [ 0.909202] ata_piix 0000:00:1f.5: MAP [ P0 -- P1 -- ] [ 0.909228] ata_piix 0000:00:1f.5: setting latency timer to 64 [ 0.909279] scsi2 : ata_piix [ 0.909326] scsi3 : ata_piix [ 0.910021] ata3: SATA max UDMA/133 cmd 0xb000 ctl 0xac00 bmdma 0xa480 irq 19 [ 0.910024] ata4: SATA max UDMA/133 cmd 0xa880 ctl 0xa800 bmdma 0xa488 irq 19 [ 0.915575] FDC 0 is a post-1991 82077 ... [ 1.716062] ata1.00: SATA link up 3.0 Gbps (SStatus 123 SControl 300) [ 1.716074] ata1.01: SATA link down (SStatus 0 SControl 300) [ 1.724318] ata1.00: ATA-8: WDC WD15EARS-00Z5B1, 80.00A80, max UDMA/133 [ 1.724322] ata1.00: 2930277168 sectors, multi 16: LBA48 NCQ (depth 0/32) [ 1.740339] ata1.00: configured for UDMA/133 [ 1.740428] scsi 0:0:0:0: Direct-Access ATA WDC WD15EARS-00Z 80.0 PQ: 0 ANSI: 5 [ 1.746788] scsi 6:0:0:0: CD-ROM ASUS DRW-1608P 1.17 PQ: 0 ANSI: 5 ... [ 1.925981] sd 0:0:0:0: [sda] 2930277168 512-byte logical blocks: (1.50 TB/1.36 TiB) [ 1.926005] sd 0:0:0:0: [sda] Write Protect is off [ 1.926007] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00 [ 1.926020] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [ 1.926092] sda:sr0: scsi3-mmc drive: 40x/40x writer cd/rw xa/form2 cdda tray [ 1.931106] Uniform CD-ROM driver Revision: 3.20 [ 1.931191] sr 6:0:0:0: Attached scsi CD-ROM sr0 ... [ 1.941936] sda1 sda2 sda3 sda4 < sda5 sda6 > [ 1.967691] sd 0:0:0:0: [sda] Attached SCSI disk [ 1.970938] sd 0:0:0:0: Attached scsi generic sg0 type 0 [ 1.970959] sr 6:0:0:0: Attached scsi generic sg1 type 5 ... [ 2.500086] EXT4-fs (sda3): mounted filesystem with ordered data mode ... [ 7.150468] EXT4-fs (sda6): mounted filesystem with ordered data mode

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  • Optimise Apache for EC2 micro instance

    - by Shiyu Sekam
    I'm running apache2 on a EC2 micro instance with ~600 mb RAM. The instance was running for almost a year without problems, but in the last weeks it just keeps crashing, because the server reached MaxClients. The server basically runs few websites, one wordpress blog(not often used), company website(most used) and 2 small sites, which are just internal. The database for the blog runs on RDS, so there's no Mysql running on this web server. When I came to the company, the server already was setup and is running apache + mod_php + prefork. We want to migrate that in the future to a nginx + php-fpm, but it still needs further testing. So for now I have to stick with the old setup. I also use CloudFlare DDOS protection in front of the server, because it was attacked a couple of the times in the last weeks. My company don't want to pay money for a better web server at this point, so I have to stick with the micro instance also. Additionally the code for the website we run is really bad and slow and sometimes a single page load can take up to 15 seconds. The whole website is dynamic and written in PHP, so caching isn't really an option here. It's a customized search for users. I've already turned off KeepAlive, which improved the performance a little bit. My prefork config looks like the following: StartServers 2 MinSpareServers 2 MaxSpareServers 5 ServerLimit 10 MaxClients 10 MaxRequestsPerChild 100 The server just becomes unresponsive after a while running and I've run the following command to see how many connections there are: netstat | grep http | wc -l 75 Trying to restart apache helps for a short moment, but after that a while the apache process(es) become unresponsive again. I've the following modules enabled(output of apache2ctl -M) Loaded Modules: core_module (static) log_config_module (static) logio_module (static) version_module (static) mpm_prefork_module (static) http_module (static) so_module (static) alias_module (shared) authz_host_module (shared) deflate_module (shared) dir_module (shared) expires_module (shared) mime_module (shared) negotiation_module (shared) php5_module (shared) rewrite_module (shared) setenvif_module (shared) ssl_module (shared) status_module (shared) Syntax OK apache2.conf # Security ServerTokens OS ServerSignature On TraceEnable On ServerName "web.example.com" ServerRoot "/etc/apache2" PidFile ${APACHE_PID_FILE} Timeout 30 KeepAlive off User www-data Group www-data AccessFileName .htaccess <Files ~ "^\.ht"> Order allow,deny Deny from all Satisfy all </Files> <Directory /> Options FollowSymLinks AllowOverride None </Directory> DefaultType none HostnameLookups Off ErrorLog /var/log/apache2/error.log LogLevel warn EnableSendfile On #Listen 80 Include /etc/apache2/mods-enabled/*.load Include /etc/apache2/mods-enabled/*.conf Include /etc/apache2/ports.conf LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined LogFormat "%h %l %u %t \"%r\" %>s %b" common LogFormat "%{Referer}i -> %U" referer LogFormat "%{User-agent}i" agent Include /etc/apache2/conf.d/*.conf Include /etc/apache2/sites-enabled/*.conf Vhost of main site <VirtualHost *:80> ServerName www.example.com ## Vhost docroot DocumentRoot /srv/www/jenkins/Web ## Directories, there should at least be a declaration for /srv/www/jenkins/Web <Directory /srv/www/jenkins/Web> AllowOverride All Order allow,deny Allow from all </Directory> ## Load additional static includes ## Logging ErrorLog /var/log/apache2/www.example.com.error.log LogLevel warn ServerSignature Off CustomLog /var/log/apache2/www.example.com.access.log combined ## Rewrite rules RewriteEngine On RewriteCond %{HTTP_HOST} !^www.example.com$ RewriteRule ^.*$ http://www.example.com%{REQUEST_URI} [R=301,L] ## Server aliases ServerAlias www.example.invalid ServerAlias example.com ## Custom fragment <Location /srv/www/jenkins/Web/library> Order Deny,Allow Deny from all </Location> <Files ~ "^\.(.+)"> Order deny,allow deny from all </Files> </VirtualHost>

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  • WPF performance : Converters vs. Triggers

    - by Joachim Kerschbaumer
    hi there, i´m currently facing a problem where i have to set properties on a bunch of framework elements depending on some other properties. i wonder how triggers and converters compare when it comes to performance. Especially MultiTriggers and IMultiValueConverters. Is there any difference? google wasn't helpful so i thought maybe some of the guys over here at SO could bring in some light. thanks, j.

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  • Diffence between FQL query and Graph API object access

    - by jwynveen
    What's the difference between accessing user data with the Facebook Graph API (http://graph.facebook.com/btaylor) and using the Graph API to make a FQL query of the same user (https://api.facebook.com/method/fql.query?query=QUERY). Also, does anyone know which of them the Facebook Developer Toolkit (for ASP.NET) uses? The reason I ask is because I'm trying to access the logged in user's birthday after they begin a Facebook Connect session on my site, but when I use the toolkit it doesn't return it. However, if I make a manual call to the Graph API for that user object, it does return it. It's possible I might have something wrong with my call from the toolkit. I think I may need to include the session key, but I'm not sure how to get it. Here's the code I'm using: _connectSession = new ConnectSession(APPLICATION_KEY, SECRET_KEY); try { if (!_connectSession.IsConnected()) { // Not authenticated, proceed as usual. statusResponse = "Please sign-in with Facebook."; } else { // Authenticated, create API instance _facebookAPI = new Api(_connectSession); // Load user user user = _facebookAPI.Users.GetInfo(); statusResponse = user.ToString(); ViewData["fb_user"] = user; } } catch (Exception ex) { //An error happened, so disconnect session _connectSession.Logout(); statusResponse = "Please sign-in with Facebook."; }

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  • NHibernate Query across multiple tables

    - by Dai Bok
    I am using NHibernate, and am trying to figure out how to write a query, that searchs all the names of my entities, and lists the results. As a simple example, I have the following objects; public class Cat { public string name {get; set;} } public class Dog { public string name {get; set;} } public class Owner { public string firstname {get; set;} public string lastname {get; set;} } Eventaully I want to create a query , say for example, which and returns all the pet owners with an name containing "ted", OR pets with a name containing "ted". Here is an example of the SQL I want to execute: SELECT TOP 10 d.*, c.*, o.* FROM owners AS o INNER JOIN dogs AS d ON o.id = d.ownerId INNER JOIN cats AS c ON o.id = c.ownerId WHERE o.lastname like '%ted%' OR o.firstname like '%ted%' OR c.name like '%ted%' OR d.name like '%ted%' When I do it using Criteria like this: var criteria = session.CreateCriteria<Owner>() .Add( Restrictions.Disjunction() .Add(Restrictions.Like("FirstName", keyword, MatchMode.Anywhere)) .Add(Restrictions.Like("LastName", keyword, MatchMode.Anywhere)) ) .CreateCriteria("Dog").Add(Restrictions.Like("Name", keyword, MatchMode.Anywhere)) .CreateCriteria("Cat").Add(Restrictions.Like("Name", keyword, MatchMode.Anywhere)); return criteria.List<Owner>(); The following query is generated: SELECT TOP 10 d.*, c.*, o.* FROM owners AS o INNER JOIN dogs AS d ON o.id = d.ownerId INNER JOIN cats AS c ON o.id = c.ownerId WHERE o.lastname like '%ted%' OR o.firstname like '%ted%' AND d.name like '%ted%' AND c.name like '%ted%' How can I adjust my query so that the .CreateCriteria("Dog") and .CreateCriteria("Cat") generate an OR instead of the AND? thanks for your help.

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  • Enhance Localization performances? (ComponentResourceManager.ApplyResources)

    - by Srodriguez
    Dear all, After experiencing some performances issues on my client side, we decided to give a try to some of the performance profilers to try to find the bottleneck or identify the guilty parts of the code. Of course, as many performance investigations, the problems comes from various things, but something I find out is that the ComponentResourceManager.ApplyResources of my user controls takes way too much time in the construction of my forms: more than 24% of the construction time is spent in the ApplyResources inside the InitializeComponent(). This seems rather a lot for only "finding a resource string and putting it in it's container". What is exactly done in the ComponentResourceManager.ApplyResources ? I guess more than searching the string, if not it wouldn't take that long. Is there a way to enhance the performances of the localization? Our software is localized in several languages, so we do need to keep this multi-lingual feature. Any recommendations regarding this issue? Thanks! PS: We are coding in C#, .NET 3.5 SP1.

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  • SQLiteQueryBuilder.buildQuery not using selectArgs?

    - by user297468
    Alright, I'm trying to query a sqlite database. I was trying to be good and use the query method of SQLiteDatabase and pass in the values in the selectArgs parameter to ensure everything got properly escaped, but it wouldn't work. I never got any rows returned (no errors, either). I started getting curious about the SQL that this generated so I did some more poking around and found SQLiteQueryBuilder (and apparently Stack Overflow doesn't handle links with parentheses in them well, so I can't link to the anchor for the buildQuery method), which I assume uses the same logic to generate the SQL statement. I did this: SQLiteQueryBuilder builder = new SQLiteQueryBuilder(); builder.setTables(BarcodeDb.Barcodes.TABLE_NAME); String sql = builder.buildQuery(new String[] { BarcodeDb.Barcodes.ID, BarcodeDb.Barcodes.TIMESTAMP, BarcodeDb.Barcodes.TYPE, BarcodeDb.Barcodes.VALUE }, "? = '?' AND ? = '?'", new String[] { BarcodeDb.Barcodes.VALUE, barcode.getValue(), BarcodeDb.Barcodes.TYPE, barcode.getType()}, null, null, null, null); Log.d(tag, "Query is: " + sql); The SQL that gets logged at this point is: SELECT _id, timestamp, type, value FROM barcodes WHERE (? = '?' AND ? = '?') However, here's what the documentation for SQLiteQueryBuilder.buildQuery says about the selectAgs parameter: You may include ?s in selection, which will be replaced by the values from selectionArgs, in order that they appear in the selection. ...but it isn't working. Any ideas?

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  • performance comparision between Zend Lucene and Java Lucene

    - by Carson
    Zend Lucene and Java Lucene are built in PHP and java repectively, and PHP language has a higher level than java. Just wondering How big the performance difference among these two, regarding to index building and data searching? Is it much more effective to let java create and rebuild index, and let php use the index?

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  • Performance of if statement versus switch statement

    - by behrk2
    Hi Everyone, I have an if statement with 16 cases (I am checking the state of four boolean variables). Would there be any value in trying to implement this differently, with nested switch statements perhaps? What is the actual performance gain of a switch statement over an if statement? Thanks!

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  • Difference in String concatenation performance

    - by Homer
    I know you should use a StringBuilder when concatenating strings but I was just wondering if there is a difference in concatenating string variables and string literals. So, is there a difference in performance in building s1, s2, and s3? string foo = "foo"; string bar = "bar"; string s1 = "foo" + "bar"; string s2 = foo + "bar"; string s3 = foo + bar;

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  • Lost connection to MySQL server during query

    - by Otavio
    I have a huge table and I need to process all rows in it. I'm always getting this Lost connection message and I'm not able to reconnect and restore the cursor to the last position it was. This is basically the code I have here: # import MySQLdb class DB: conn = None def connect(self): self.conn = MySQLdb.connect('hostname', 'user', '*****', 'some_table', cursorclass=MySQLdb.cursors.SSCursor) def query(self, sql): try: cursor = self.conn.cursor() cursor.execute(sql) except (AttributeError, MySQLdb.OperationalError): self.connect() cursor = self.conn.cursor() cursor.execute(sql) return cursor # # db = DB() sql = "SELECT bla FROM foo" data = db.query(sql) for row in data: do_something(row) # But I'm always getting this: # Traceback (most recent call last): File "teste.py", line 124, in <module> run() File "teste.py", line 109, in run for row in data: File "/usr/lib64/python2.5/site-packages/MySQLdb/cursors.py", line 417, in next row = self.fetchone() File "/usr/lib64/python2.5/site-packages/MySQLdb/cursors.py", line 388, in fetchone r = self._fetch_row(1) File "/usr/lib64/python2.5/site-packages/MySQLdb/cursors.py", line 285, in _fetch_row return self._result.fetch_row(size, self._fetch_type) _mysql_exceptions.OperationalError: (2013, 'Lost connection to MySQL server during query') Exception _mysql_exceptions.OperationalError: (2013, 'Lost connection to MySQL server during query') in <bound method SSCursor.__del__ of <MySQLdb.cursors.SSCursor object at 0x7f7e3c8da410>> ignored # Do you have any idea?

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  • HQL Query Not Running

    - by Sarang
    select new UpdateCountDataBean(count(elements(am.actionId)) as noOfUpdates, am.pname as name) from ActivityMaster am group by am.pname The UpdateCountDataBean is created by me while the second class i.e. ActivityMaster is POJO class. java.lang.NullPointerException at org.hibernate.hql.ast.tree.MethodNode.handleElements(MethodNode.java:158) at org.hibernate.hql.ast.tree.MethodNode.resolveCollectionProperty(MethodNode.java:109) at org.hibernate.hql.ast.tree.CollectionFunction.resolve(CollectionFunction.java:22) at org.hibernate.hql.ast.HqlSqlWalker.processFunction(HqlSqlWalker.java:835) at org.hibernate.hql.antlr.HqlSqlBaseWalker.collectionFunction(HqlSqlBaseWalker.java:2558) at org.hibernate.hql.antlr.HqlSqlBaseWalker.aggregateExpr(HqlSqlBaseWalker.java:2907) at org.hibernate.hql.antlr.HqlSqlBaseWalker.count(HqlSqlBaseWalker.java:2483) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectExpr(HqlSqlBaseWalker.java:1971) at org.hibernate.hql.antlr.HqlSqlBaseWalker.aliasedSelectExpr(HqlSqlBaseWalker.java:2057) at org.hibernate.hql.antlr.HqlSqlBaseWalker.constructor(HqlSqlBaseWalker.java:2226) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectExpr(HqlSqlBaseWalker.java:1952) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectExprList(HqlSqlBaseWalker.java:1825) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectClause(HqlSqlBaseWalker.java:1394) at org.hibernate.hql.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:553) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:281) at org.hibernate.hql.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:229) at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:228) at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:160) at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:111) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:77) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:56) at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:72) at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:133) at org.hibernate.impl.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:112) at org.hibernate.impl.SessionImpl.createQuery(SessionImpl.java:1623)

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  • C# Generate MRTG/RRD like Graphs Performance graphs?

    - by BlackTea
    I have a database with Performance counter data and i would like to show this on a ASP.net page but the thing is i don't want to use Flash based charting solution or a Javascript based solution i would like to just generate images and use those I want the images to be like those of RRD or MRTG. I'm trying to find out how i can create graphs like the following http://oss.oetiker.ch/rrdtool/stream-pop.png http://oss.oetiker.ch/rrdtool/gallery/index.en.html Any ideas?

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  • What might cause the big overhead of making a HttpWebRequest call?

    - by Dimitri C.
    When I send/receive data using HttpWebRequest (on Silverlight, using the HTTP POST method) in small blocks, I measure the very small throughput of 500 bytes/s over a "localhost" connection. When sending the data in large blocks, I get 2 MB/s, which is some 5000 times faster. Does anyone know what could cause this incredibly big overhead? Update: I did the performance measurement on both Firefox 3.6 and Internet Explorer 7. Both showed similar results. Update: The Silverlight client-side code I use is essentially my own implementation of the WebClient class. The reason I wrote it is because I noticed the same performance problem with WebClient, and I thought that the HttpWebRequest would allow to tweak the performance issue. Regrettably, this did not work. The implementation is as follows: public class HttpCommChannel { public delegate void ResponseArrivedCallback(object requestContext, BinaryDataBuffer response); public HttpCommChannel(ResponseArrivedCallback responseArrivedCallback) { this.responseArrivedCallback = responseArrivedCallback; this.requestSentEvent = new ManualResetEvent(false); this.responseArrivedEvent = new ManualResetEvent(true); } public void MakeRequest(object requestContext, string url, BinaryDataBuffer requestPacket) { responseArrivedEvent.WaitOne(); responseArrivedEvent.Reset(); this.requestMsg = requestPacket; this.requestContext = requestContext; this.webRequest = WebRequest.Create(url) as HttpWebRequest; this.webRequest.AllowReadStreamBuffering = true; this.webRequest.ContentType = "text/plain"; this.webRequest.Method = "POST"; this.webRequest.BeginGetRequestStream(new AsyncCallback(this.GetRequestStreamCallback), null); this.requestSentEvent.WaitOne(); } void GetRequestStreamCallback(IAsyncResult asynchronousResult) { System.IO.Stream postStream = webRequest.EndGetRequestStream(asynchronousResult); postStream.Write(requestMsg.Data, 0, (int)requestMsg.Size); postStream.Close(); requestSentEvent.Set(); webRequest.BeginGetResponse(new AsyncCallback(this.GetResponseCallback), null); } void GetResponseCallback(IAsyncResult asynchronousResult) { HttpWebResponse response = (HttpWebResponse)webRequest.EndGetResponse(asynchronousResult); Stream streamResponse = response.GetResponseStream(); Dim.Ensure(streamResponse.CanRead); byte[] readData = new byte[streamResponse.Length]; Dim.Ensure(streamResponse.Read(readData, 0, (int)streamResponse.Length) == streamResponse.Length); streamResponse.Close(); response.Close(); webRequest = null; responseArrivedEvent.Set(); responseArrivedCallback(requestContext, new BinaryDataBuffer(readData)); } HttpWebRequest webRequest; ManualResetEvent requestSentEvent; BinaryDataBuffer requestMsg; object requestContext; ManualResetEvent responseArrivedEvent; ResponseArrivedCallback responseArrivedCallback; } I use this code to send data back and forth to an HTTP server.

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  • Derby vs PostgreSql Performance Comparison

    - by Austin
    We are doing research right now on whether to switch our postgresql db to an embedded Derby db. Both would be using glassfish 3 for our data layer. Anybody have any opinions or knowledge that could help us decide? Thanks! edit: we are writing some performance tests ourselves right now. Looking for answers more based on experience / first hand knowledge

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  • LINQ self referencing query

    - by Chris
    I have the following SQL query: select p1.[id], p1.[useraccountid], p1.[subject], p1.[message], p1.[views], p1.[parentid], case when p2.[created] is null then p1.[created] else p2.[created] end as LastUpdate from forumposts p1 left join ( select parentid, max(created) as [created] from forumposts group by parentid ) p2 on p2.parentid = p1.id where p1.[parentid] is null order by LastUpdate desc Using the following class: public class ForumPost : PersistedObject { public int Views { get; set; } public string Message { get; set; } public string Subject { get; set; } public ForumPost Parent { get; set; } public UserAccount UserAccount { get; set; } public IList<ForumPost> Replies { get; set; } } How would I replicate such a query in LINQ? I've tried several variations, but I seem unable to get the correct join syntax. Is this simply a case of a query that is too complicated for LINQ? Can it be done using nested queries some how? The purpose of the query is to find the most recently updated posts i.e. replying to a post would bump it to the top of the list. Replies are defined by the ParentID column, which is self-referencing.

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  • Variables versus constants versus associative arrays in PHP

    - by susmits
    I'm working on a small project, and need to implement internationalization support somehow. I am thinking along the lines of using constants to define a lot of symbols for text in one file, which could be included subsequently. However, I'm not sure if using variables is faster, or if I can get away with using associative arrays without too much of a performance hit. What's better for defining constant values in PHP, performance-wise -- constants defined using define("FOO", "..."), or simple variables like $foo = "...", or associative arrays like $symbols["FOO"]?

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  • Whats wrong with this HQL query?

    - by ManBugra
    did i encounter a hibernate bug or do i have an error i dont see: select enty.number from EntityAliasName enty where enty.myId in ( select cons.myId from Consens cons where cons.number in ( select ord.number from Orders ord where ord.customer = :customer and ord.creationDate < ( select max(ord.creationDate) from Orders ord where ord.customer = :customer ) ) ) what i do get is the following: org.hibernate.util.StringHelper.root(StringHelper.java:257) Caused by: java.lang.NullPointerException at org.hibernate.util.StringHelper.root(StringHelper.java:257) at org.hibernate.persister.entity.AbstractEntityPersister.getSubclassPropertyTableNumber(AbstractEntityPersister.java:1391) at org.hibernate.persister.entity.BasicEntityPropertyMapping.toColumns(BasicEntityPropertyMapping.java:54) at org.hibernate.persister.entity.AbstractEntityPersister.toColumns(AbstractEntityPersister.java:1367) at org.hibernate.hql.ast.tree.FromElement.getIdentityColumn(FromElement.java:320) at org.hibernate.hql.ast.tree.IdentNode.resolveAsAlias(IdentNode.java:154) at org.hibernate.hql.ast.tree.IdentNode.resolve(IdentNode.java:100) at org.hibernate.hql.ast.tree.FromReferenceNode.resolve(FromReferenceNode.java:117) at org.hibernate.hql.ast.tree.FromReferenceNode.resolve(FromReferenceNode.java:113) at org.hibernate.hql.ast.HqlSqlWalker.resolve(HqlSqlWalker.java:854) at org.hibernate.hql.antlr.HqlSqlBaseWalker.propertyRef(HqlSqlBaseWalker.java:1172) at org.hibernate.hql.antlr.HqlSqlBaseWalker.propertyRefLhs(HqlSqlBaseWalker.java:5167) at org.hibernate.hql.antlr.HqlSqlBaseWalker.propertyRef(HqlSqlBaseWalker.java:1133) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectExpr(HqlSqlBaseWalker.java:1993) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectExprList(HqlSqlBaseWalker.java:1932) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectClause(HqlSqlBaseWalker.java:1476) at org.hibernate.hql.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:580) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:288) at org.hibernate.hql.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:231) at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:254) at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:185) at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:136) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:101) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:80) at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:94) at org.hibernate.impl.SessionFactoryImpl.checkNamedQueries(SessionFactoryImpl.java:484) at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:394) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1341) using: Hibernate 3.3.2.GA / postgresql

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  • What is the fastest way to unzip textfiles in Matlab during a function?

    - by Paul
    Hello all, I would like to scan text of textfiles in Matlab with the textscan function. Before I can open the textfile with fid = fopen('C:\path'), I need to unzip the files first. The files have the extension: *.gz There are thousands of files which I need to analyze and high performance is important. I have two ideas: (1) Use an external program an call it from the command line in Matlab (2) Use a Matlab 'zip'toolbox. I have heard of gunzip, but don't know about its performance. Does anyone knows a way to unzip these files as quick as possible from within Matlab? Thanks!

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  • Performance comparison of Dictionaries

    - by Hun1Ahpu
    I'm interested in performance values (big-O analysis) of Lookup and Insert operation for .Net Dictionaries: HashTable, SortedList, StringDictionary, ListDictionary, HybridDictionary, NameValueCollection Link to a web page with the answer works for me too.

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  • Is this possible to join tables in doctrine ORM without using relations?

    - by piemesons
    Suppose there are two tables. Table X-- Columns: id x_value Table Y-- Columns: id x_id y_value Now I dont want to define relationship in doctrine classes and i want to retrieve some records using these two tables using a query like this: Select x_value from x, y where y.id="variable_z" and x.id=y.x_id; I m not able to figure out how to write query like this in doctrine orm EDIT: Table structures: Table 1: CREATE TABLE IF NOT EXISTS `image` ( `id` int(11) NOT NULL AUTO_INCREMENT, `random_name` varchar(255) NOT NULL, `user_id` int(11) NOT NULL, `community_id` int(11) NOT NULL, `published` varchar(1) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=259 ; Table 2: CREATE TABLE IF NOT EXISTS `users` ( `id` int(11) NOT NULL AUTO_INCREMENT, `city` varchar(20) DEFAULT NULL, `state` varchar(20) DEFAULT NULL, `school` varchar(50) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=20 ; Query I am using: $q = new Doctrine_RawSql(); $q ->select('{u.*}, {img.*}') ->from('users u LEFT JOIN image img ON u.id = img.user_id') ->addComponent('u', 'Users u') ->addComponent('img', 'u.Image img') ->where("img.community_id='$community_id' AND img.published='y' AND u.state='$state' AND u.city='$city ->orderBy('img.id DESC') ->limit($count+12) ->execute(); Error I am getting: Fatal error: Uncaught exception 'Doctrine_Exception' with message 'Couldn't find class u' in C:\xampp\htdocs\fanyer\doctrine\lib\Doctrine\Table.php:290 Stack trace: #0 C:\xampp\htdocs\fanyer\doctrine\lib\Doctrine\Table.php(240): Doctrine_Table- >initDefinition() #1 C:\xampp\htdocs\fanyer\doctrine\lib\Doctrine\Connection.php(1127): Doctrine_Table->__construct('u', Object(Doctrine_Connection_Mysql), true) #2 C:\xampp\htdocs\fanyer\doctrine\lib\Doctrine\RawSql.php(425): Doctrine_Connection- >getTable('u') #3 C:\xampp\htdocs\fanyer\doctrine\models\Image.php(33): Doctrine_RawSql- >addComponent('img', 'u.Image imga') #4 C:\xampp\htdocs\fanyer\community_images.php(31): Image->get_community_images_gallery_filter(4, 0, 'AL', 'ALBERTVILLE') #5 {main} thrown in C:\xampp\htdocs\fanyer\doctrine\lib\Doctrine\Table.php on line 290

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  • I'm trying to populate a MySQL table with some data, but, mysqli won't let me insert every 10th stat

    - by Tunji Gbadamosi
    I want to initialise a 'ticket' table with some ticket IDs. To do this, I want to insert 120 ticket IDs into the table. However, at every 10th statement, MySQL tells me that the ID already exists and thus won't let me insert it. Here's my code: //make a query $insert_ticket_query = "INSERT INTO ticket (id) VALUES (?)"; $insert_ticket_stmt = $mysqli->stmt_init(); $insert_ticket_stmt->prepare($insert_ticket_query); $insert_ticket_stmt->bind_param('s', $ticket_id); $mysqli->autocommit(FALSE); //start transaction for($i=0;$i<NO_GUESTS;$i++){ $id = generate_id($i); $ticket_id = format_id($id, $prefix['ticket'], $suffix['ticket']); $t_id = $ticket_id; //echo '<p>'.$ticket_id.'</p>'; //$result = $mysqli->query("SELECT * FROM ticket WHERE id='".$ticket_id."'"); //$row_count = $result->num_rows; if(($result = $mysqli->query("SELECT * FROM ticket WHERE id='".$t_id."'")) == FALSE){ $result->close(); if($insert_ticket_stmt->execute()){ $mysqli->commit(); echo "<p>".$t_id."added to the ticket table!</p>"; } else{ $mysqli->rollback(); echo "problem inserting'".$t_id."' to the ticket table"; } } else{ echo "<p>".$t_id."already exists, so not adding it!</p>"; $result->close(); } } $mysqli->autocommit(TRUE); $insert_ticket_stmt->close(); ?>

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