Re^2: Preventing database handles from going stale

Oooooh... Thanks for the tip! I am forking, but the child process should just be regenerating a graphic using in-memory data, then exiting without touching the db. I'll double-check to be sure that it's not trying to use the connection while doing any of its work.

Oh. Wait. I just remembered something.

I'm using a homegrown DBI-helper module that exports a $dbh and has centralized db connect code and so forth so all my other modules don't have to worry so much about that stuff. It also has an

END {
  $dbh->disconnect;
}
[download]

block. The forked children aren't using the db for anything, but if they execute that END block when they exit...

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Re^3: Preventing database handles from going stale by kyle (Abbot) on Feb 05, 2007 at 19:56 UTC
Have the child set `$dbh->{InactiveDestroy} = 1;` and then undef the `$dbh`. That should keep it from disconnecting the parent's connection. After that, you'll just have to fix the `END` block so it doesn't try to call `disconnect` on an undefined value. `END { $dbh->disconnect if $dbh; }` [download] I wrote about this and more in DBI, fork, and clone..	[reply] [d/l] [select]
Re^4: Preventing database handles from going stale by dsheroh (Monsignor) on Feb 06, 2007 at 01:35 UTC
Excellent suggestion and some good info in your linked writeup, too. Thanks!	[reply]
Re^3: Preventing database handles from going stale by ikegami (Patriarch) on Feb 05, 2007 at 19:47 UTC
but if they execute that END block when they exit... They do. Even without the `END` block, the problem would still exists since the child would call `$dbh`'s destructor which calls `disconnect` (after issuing a warning). Sorry, I don't have any good solution short of connecting after the `fork`. Maybe you can create a pool of reusable children early on? Maybe you can `exec` within the child, even if only to relaunch Perl? Maybe you can add to a job list which monitored by `cron` job instead of forking?	[reply] [d/l] [select]