Bug #11993 Updated: mysql_close closes incorrect db handler

ID: 11993 Updated by: sniper Reported By: atiware@metasuccess.net Old Status: Status: Open Bug Type: MySQL related Operating System: Debian 2.19 PHP Version: 4.0.6 New Comment: missing status Previous Comments: ------------------------------------------------------------------------ [2001-07-11 13:58:35] atiware@metasuccess.net hi zak, thanks for your answer. in my opinion, php must have some matrix, where you stores the number of connect and close calls with the connection id. this will probably solve the problem. ps: i use these multiple connections in oop environment, where a global connection id, is not the best idea. or? ati ------------------------------------------------------------------------ [2001-07-11 06:58:00] zak@php.net Here is a refinement on this bug: Multiple duplicate calls to mysql_connect are supposed to return the same link ID. Each call after the first call will only return the link ID of the first (if everything goes as planned, the connection is still good, etc...). i.e. var_dump (mysql_connect() === mysql_connect()); Given this behavior, how should mysql_close() behave? I would expect that calling mysql_close ($id) would close the connection that both $id and $id2 refer to. Behavior is not this - instead it is quite odd... Multiple calls to mysql_close are required to close multiple duplicate calls to mysql_connect. i.e. var_dump ($db = mysql_connect ()); var_dump ($db = mysql_connect ()); var_dump (mysql_close ($db)); // Maybe this closes the default connection? var_dump (mysql_close ($db)); However, if more than two calls to mysql_connect are made, followed by a corresponding number of calls to mysql_close, the mysql_close calls start to fail. i.e. $max = 10; for ($x=0; $x<$max; ++$x) { var_dump ($db = mysql_connect()); } for ($x=0; $x<$max; ++$x) { var_dump (mysql_close ($db)); } Now, throw change the call to mysql_close($db) to mysql_close() - everything seems to work as expected. However as soon as you add a call to mysql_query after the call to mysql_close, the link will *never* die - no matter how many times you close it. Finally, put a call to mysql_close ($db) between the two loops. The next call to mysql_close() will fail with an error, while subsequent calls will succeed - once again, the link will never die. Things get even stranger when this behavior is encountered within recursive function calls - however, I guess that this is a side effect of the behavior described above. It looks like there is some complex/odd interactions happening with the code that closes mysql links and the code that sets and uses the default link -- however, this is quite far over my head! Anyone else have any ideas? :) ------------------------------------------------------------------------ [2001-07-11 05:07:29] zak@php.net Dear Ati, When you enter a bug report, please make the script that reproduces the error as short and simple as possible. I do not believe that the problem that you are encountering is a bug - you just have too many connections open at once. Try this script: <pre> <?php error_reporting (0); function test () { static $count = 0; if (++$count < 20) { echo "Opening $count:"; var_dump ($db = mysql_connect ('localhost:3306', replace_me, replace_me)); test (); --$count; echo "Closing $count:"; var_dump (mysql_close ($db)); } } test (); ?> </pre> Now try it with mysql_pconnect -- does the error go away? It does for me. In most cases, you will only need a *single* connection to a mysql database -- not multiple. This may still be a bug - two or more calls to mysql_connect with the same arguments should only result in one connection being opened. Each call will return the same connection ID. ------------------------------------------------------------------------ [2001-07-10 21:31:02] atiware@metasuccess.net i have tried out with the following configurations: server1: php-4.0.6/mysql.3.23.32/apache-1.3.20/debian 2.19 server2: php-4.0.6/mysql.3.23.37/apache-1.3.20/debian 2.19 the result is the same as with php-4.0.4pl1 please check this... thanks ati ------------------------------------------------------------------------ [2001-07-09 19:22:19] atiware@metasuccess.net debian 2.19 / mysql 3.23.37 / php 4.0.4pl1 configure section of phpinfo(): './configure' '--with-gd' '--with-jpeg-dir' '--with-png-dir' '--with-tiff-dir' '--disable-posix' '--enable-ftp' '--enable-calendar' '--with-imap' '--with-mcrypt' '--with-swf=/usr/local/swf' '--with-apache=/home/atiware/apache_1.3.14' '--enable-track-vars' '--with-mysql=/usr/local' the sript that reproduces the problem: --cut here-- <?php define("DEEPLIMIT",10); //maximal deep of recursive calls /* !! please edit this settings !! */ define("MYHOST","localhost"); define("MYPORT","3306"); define("MYUSER","YOUR_USERNAME"); define("MYPWD","YOUR_PASSWORD"); /* this function reproduces the error */ function recursive($deep,$persistent=false) { if ($deep<=DEEPLIMIT) { //down side if ($persistent) $db=mysql_pconnect(MYHOST.":".MYPORT,MYUSER,MYPWD); //creating persistent mysql connection and storing in a local variable else $db=mysql_connect(MYHOST.":".MYPORT,MYUSER,MYPWD); //creating mysql connection and storing in a local variable $res=@mysql_query("select 1 as ONE",$db); //some dummy query $mr=null; if (@mysql_num_rows($res)) { $mr=@mysql_fetch_array($res); } //and now write the result printf("%sRecursive: Deep: %s, DownSideQuery: %s<br>\n",str_repeat(">",$deep),$deep,(int)$mr["ONE"]); recursive($deep+1,$persistent); //up side $res=@mysql_query("select 1 as ONE",$db); //using previously created connection ($db), if exists ;) $mr=null; if (@mysql_num_rows($res)) { $mr=@mysql_fetch_array($res); } //write result again printf("%sRecursive: Deep: %s, UpSideQuery: %s",str_repeat(">",$deep),$deep,(int)$mr["ONE"]); //error check if (!(int)$mr["ONE"]) printf("&nbsp;&nbsp;<b>!?ERROR!? why 0?</b>"); printf("<br>\n"); @mysql_close($db); //closing mysql connection } else { printf("Limit occured (%s). Turning back...<br>\n",DEEPLIMIT); } } echo "Trying with <b>mysql_connect()</b><br>\n"; recursive(1); echo "<br><br>\n\n"; echo "Trying with <b>mysql_pconnect()</b><br>\n"; recursive(1,true); ?> --cut here-- the output of the script: Trying with mysql_connect() >Recursive: Deep: 1, DownSideQuery: 1 >>Recursive: Deep: 2, DownSideQuery: 1 >>>Recursive: Deep: 3, DownSideQuery: 1 >>>>Recursive: Deep: 4, DownSideQuery: 1 >>>>>Recursive: Deep: 5, DownSideQuery: 1 >>>>>>Recursive: Deep: 6, DownSideQuery: 1 >>>>>>>Recursive: Deep: 7, DownSideQuery: 1 >>>>>>>>Recursive: Deep: 8, DownSideQuery: 1 >>>>>>>>>Recursive: Deep: 9, DownSideQuery: 1 >>>>>>>>>>Recursive: Deep: 10, DownSideQuery: 1 Limit occured (10). Turning back... >>>>>>>>>>Recursive: Deep: 10, UpSideQuery: 1 >>>>>>>>>Recursive: Deep: 9, UpSideQuery: 1 >>>>>>>>Recursive: Deep: 8, UpSideQuery: 1 >>>>>>>Recursive: Deep: 7, UpSideQuery: 1 >>>>>>Recursive: Deep: 6, UpSideQuery: 1 >>>>>Recursive: Deep: 5, UpSideQuery: 0 !?ERROR!? why 0? >>>>Recursive: Deep: 4, UpSideQuery: 0 !?ERROR!? why 0? >>>Recursive: Deep: 3, UpSideQuery: 0 !?ERROR!? why 0? >>Recursive: Deep: 2, UpSideQuery: 0 !?ERROR!? why 0? >Recursive: Deep: 1, UpSideQuery: 0 !?ERROR!? why 0? Trying with mysql_pconnect() >Recursive: Deep: 1, DownSideQuery: 1 >>Recursive: Deep: 2, DownSideQuery: 1 >>>Recursive: Deep: 3, DownSideQuery: 1 >>>>Recursive: Deep: 4, DownSideQuery: 1 >>>>>Recursive: Deep: 5, DownSideQuery: 1 >>>>>>Recursive: Deep: 6, DownSideQuery: 1 >>>>>>>Recursive: Deep: 7, DownSideQuery: 1 >>>>>>>>Recursive: Deep: 8, DownSideQuery: 1 >>>>>>>>>Recursive: Deep: 9, DownSideQuery: 1 >>>>>>>>>>Recursive: Deep: 10, DownSideQuery: 1 Limit occured (10). Turning back... >>>>>>>>>>Recursive: Deep: 10, UpSideQuery: 1 >>>>>>>>>Recursive: Deep: 9, UpSideQuery: 1 >>>>>>>>Recursive: Deep: 8, UpSideQuery: 1 >>>>>>>Recursive: Deep: 7, UpSideQuery: 1 >>>>>>Recursive: Deep: 6, UpSideQuery: 1 >>>>>Recursive: Deep: 5, UpSideQuery: 1 >>>>Recursive: Deep: 4, UpSideQuery: 1 >>>Recursive: Deep: 3, UpSideQuery: 1 >>Recursive: Deep: 2, UpSideQuery: 1 >Recursive: Deep: 1, UpSideQuery: 1 ------------------------------------------------------------------------ Edit this bug report at http://bugs.php.net/?id=11993&edit=1