From: alan dot blotz at students dot uni-mainz dot de Operating system: Debian Lenny PHP version: 5.2.6 PHP Bug Type: MySQL related Bug description: pcntl_fork() with MySQL queries
Description: ------------ Already a long time ago the bug http://bugs.php.net/bug.php?id=38228 was active, but I experienced some problems with the pcntl_fork() function today. I already fixed the problem with multiple children connecting to the MySQL server by using mysql_connect(..., true) or mysql_pconnect() (the latter I'm using right now). My problem is, that with any of these methods I'm partly getting wrong results to queries (see code). This really NOT happening always, just sometimes when you don't expect it. I can't post the original code due to copyrights, but the example below should give you an idea of what is happening. I'm working with multiple children in my application (executed as CLI), at least five at a time. Is it perhaps a memory problem of PHP and / or MySQL? Alan Reproduce code: --------------- // Queries for five children for ($i = 0; $i < 5; $i++) { // If I am the child if (!pcntl_fork()) { switch ($i) { case 0: $sql = 'SELECT a, b FROM t'; break; case 1: $sql = 'SELECT c FROM s'; break; case 2: $sql = 'SELECT x FROM s'; break; case 3: $sql = 'SELECT a, b, d FROM t'; break; case 4: $sql = 'SELECT d FROM t'; break; } $result = mysql_query($sql); // Get the result from DB with mysql_fetch_array() for example } } Expected result: ---------------- Result of columns a and b from table t in first child Result of column c from table s in second child Result of column x from table s in third child Result of columns a, b and d from table t in fourth child Result of column d from table t in fifth child Actual result: -------------- For example (some worst case): Nothing in first child Result of column x from table s in second child Result of column c from table s in third child Result of columns a and b from table t in fourth child Result of column d from table t in fifth child -- Edit bug report at http://bugs.php.net/?id=45590&edit=1 -- Try a CVS snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=45590&r=trysnapshot52 Try a CVS snapshot (PHP 5.3): http://bugs.php.net/fix.php?id=45590&r=trysnapshot53 Try a CVS snapshot (PHP 6.0): http://bugs.php.net/fix.php?id=45590&r=trysnapshot60 Fixed in CVS: http://bugs.php.net/fix.php?id=45590&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=45590&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=45590&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=45590&r=needscript Try newer version: http://bugs.php.net/fix.php?id=45590&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=45590&r=support Expected behavior: http://bugs.php.net/fix.php?id=45590&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=45590&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=45590&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=45590&r=globals PHP 4 support discontinued: http://bugs.php.net/fix.php?id=45590&r=php4 Daylight Savings: http://bugs.php.net/fix.php?id=45590&r=dst IIS Stability: http://bugs.php.net/fix.php?id=45590&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=45590&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=45590&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=45590&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=45590&r=mysqlcfg
