#26490 [Com]: Lost connection to MySQL server during query

ID: 26490 Comment by: gmartine at adinet dot com dot uy Reported By: chris dot noden at monstermob dot com Status: Verified Bug Type: MySQL related Operating System: * PHP Version: 4CVS, 5CVS (2004-03-13) New Comment: Hi, I have this very same error using "php 4.3.7" / "mysql 4.0.20a" under windows 2000. Regards. Previous Comments: ------------------------------------------------------------------------ [2004-06-22 23:30:25] phpbug at nathandial dot com I've got the same bug on gentoo. PHP 4.3.6, mysql 4.0.18 ------------------------------------------------------------------------ [2004-06-20 20:22:08] theseer@php.net I cannot speak for chris but at least we are running Redhat/Fedora Systems using MySQL rpms from mysql.com. I will check the workarounds mentioned on the redhat page and report back. ------------------------------------------------------------------------ [2004-06-11 00:23:42] Ryan dot Springer at billingconcepts dot com Is everyone who is effected by this bug running Red Hat? If so, this may be a libc problem. See: http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=75128 ------------------------------------------------------------------------ [2004-03-11 11:39:40] theseer@php.net This happens on the following versions: php 4.3.3, 4.3.4, 4.3.5RC3 with bundled or external mysql client code with shared or buildin MySQL Server Version here is 4.0.18 The MySQL Log shows this row on a 'connection lost' error: Aborted connection 2048 to db: [....] (Got an error reading communication packets) ------------------------------------------------------------------------ [2004-03-11 11:35:27] theseer@php.net Since i just stumbled across the very same problem, i wrote a small (?) testcode to check it. It seems like using pconnect in favor of a 'normal' connect fixes the problem for the testcode, while it does not for my reallife application. The code assumes a database with at least 100 rows. Structure as follows: CREATE TABLE debug2 ( ID int(11) NOT NULL auto_increment, CODE varchar(10) NOT NULL default '', PRIMARY KEY (ID), ) TYPE=MyISAM This is the testcode, run it from cli ;) <?php function do_something($ppid,$data) { $db=mysql_connect('db.local.dev','dev','dev'); echo mysql_error(); mysql_selectdb('fpostv4',$db); echo mysql_error(); foreach ($data as $row) { $sql="update debug2 set CODE='1' where ID='{$row['ID']}'"; echo "[$ppid] $sql\n"; $rc=mysql_query($sql); echo mysql_error(); } } $db=mysql_connect('db.local.dev','dev','dev'); mysql_selectdb('fpostv4',$db); echo mysql_error(); $rc=mysql_query('update debug2 set code=""'); echo mysql_error(); $rc=mysql_query('select * from debug2'); echo mysql_error(); for ($t=0; $t<10; $t++) { $pid = pcntl_fork(); if ( $pid == -1 ) { die('Error during fork() - halting'); } elseif ( $pid == 0 ) { $ppid=getmypid(); mysql_data_seek($rc,$t*10); echo mysql_error(); for ($x=0; $x<10; $x++) { $data[]=mysql_fetch_assoc($rc); } do_something($ppid,$data); die(); } else { $pidlist[]=$pid; $sendPos += $perThread; } } // wait for them to finish... while (count($pidlist)) { foreach ($pidlist as $key => $ppid) { $tmp=pcntl_waitpid($ppid, $temp, WNOHANG); if ($tmp!=0 ) { unset($pidlist[$key]); } } sleep(2); } ?> You may have to run the code multiple times to actually see the problem. The "Lost connection" error doesn't occur on a fixed rate or value. You may be 'lucky' and don't hit it at all in a run.. Feel free to contact me in irc ( freenode / ircnet ) ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/26490 -- Edit this bug report at http://bugs.php.net/?id=26490&edit=1