What happens to a running PHP script with MySQL queries during a server restart?

Question

I'm running a PHP script that converts a few hundred thousand records from a remote MySQL server to the local one. A few times during the transfer, the error_logs shows ...

[Wed Jul 03 17:02:36 2013] [notice] Graceful restart requested, doing restart
[Wed Jul 03 17:02:37 2013] [notice] SSL FIPS mode disabled
[Wed Jul 03 17:02:37 2013] [notice] Apache/2.2.22 (Unix) mod_ssl/2.2.22 OpenSSL/1.0.0-fips mod_bwlimited/1.4 PHP/5.3.16 configured -- resuming normal operations

It's rare, and I can't find a reason for it, but the script seems to continue as though nothing happened. Testing if data was lost would be very cumbersome. So I'm wondering, what happens if a MySQL query is interrupted? And why does PHP seems to ignore the restart entirely, and just continue running as though nothing happened? Any thoughts on how/what to test?

Answer 1

That's an Apache log, not a PHP log. Your script is probably running in CLI (command line) so an Apache restart won't affect it. Otherwise it may have been restarted with -k graceful which will allow child processes to complete.

So I'm wondering, what happens if a MySQL query is interrupted

If MySQL is restarted, the script will fail (unless the programmer incorporated some extra robust error handling to deal with that situation).