I am writing a server that connects to MySQL via DBI (driver and/or ODBC).
I have appended a piece of simplified test code illustrating the problem.
Here are my observations.
- Problem only occurs under Windows (Win2K) and never under Unix (FreeBSD).
- Any child fork that connects to MySQL after another child fork has
connected, disconnected and exited will generate an address fault.
- Child forks may connect to MySQL without error, as long as no child fork
has exited.
- Effect is identical for DBI:MySQL and DBI:ODBC:MyODBC-DSN.
Thanks for any help.
____________________________________
#!/usr/local/bin/perl
# Usage: perl testForkDBIMySql.pl
# Test script creates 3 to 5 child processes, each identical which open DBI
connection
# to MySQL, sleep, close connection and potentially exit. As configured,
will create
# memory address error under Win2K after 2-second task exits. See inline
comments for
# testing options.
use strict;
use DBI;
my $user = your_username_here;
my $pass = your_password_here;
sub serviceTask {
my ($time) = @_;
print "$$ Child $time starting ".gmtime()."\n";
# Comment out one or other of connect statements; shouldn't alter result.
my $dbh = DBI->connect("DBI:mysql:iView", $user, $pass);
# my $dbh = DBI->connect("DBI:ODBC:MySQL-ODBC", $user, $pass);
print "$$ Child $time started ".gmtime()."\n";
if ($dbh) {
sleep $time;
print "$$ Child $time ending ".gmtime()."\n";
my $rc = $dbh->disconnect;
print "$$ Child $time ended ".gmtime()."\n";
}
# Uncomment the sleep to prevent child processes from exiting. Should
prevent
# memory errors.
# WARNING: Child processes will not die and memory will not be released
# sleep (10) while (1);
print "$$ Child $time exit ".gmtime()."\n";
}
# Delete " = 1" for case where all children start before any exits. Should
avoid
# starting new child after another child has exited.
my $earlyExit = 1;
my @times = $earlyExit ? (2, 3, 5, 7, 11) : (5, 7, 11);
print "$$ Parent start ".gmtime()."\n";
foreach my $time (@times) {
my $pid;
if (!defined($pid = fork)) {
print "Cannot fork: $!";
} elsif ($pid) {
print "$$ Parent $time fork ".gmtime()."\n";
} else {
exit &serviceTask($time);
}
sleep 1;
}
print "$$ Parent end ".gmtime()."\n";
1
---------------------------------------------------------------------
Before posting, please check:
http://www.mysql.com/manual.php (the manual)
http://lists.mysql.com/ (the list archive)
To request this thread, e-mail <[EMAIL PROTECTED]>
To unsubscribe, e-mail <[EMAIL PROTECTED]>
Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
