Re: Pg + perl + apache

From: Lincoln Yeoh <lyeoh(at)pop(dot)jaring(dot)my>
To: slyph(at)alum(dot)mit(dot)edu, pgsql-general(at)postgresql(dot)org
Subject: Re: Pg + perl + apache
Date: 2004-02-18 10:30:58
Message-ID: 5.2.1.1.1.20040218181941.02755b60@mbox.jaring.my
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You could try something like this:

Assuming you are using perl+DBI (as per your examples).

If you are using modperl:
[modperl can override the "connect to db" for connection reuse/pooling]

begin cgi web app:
connect to db
rollback
do stuff
do more stuff
commit if ok
by default rollback
disconnect.

If you are using fastcgi:
[fastcgi - explicit DB connection reuse]
connect to db
while (fastcgi connection) {
rollback
do stuff
do more stuff
commit if ok
by default rollback
}
rollback
disconnect

You probably want to do a rollback before you do stuff so that the
transaction times are correct. AFAIK Perl DBI automatically does a BEGIN
after a rollback or commit, so if the previous transaction was rolled back
or committed 1 hour ago, you'd be reusing a transaction that begun 1 hour
ago for something that's happening now.

This would cause select 'now'::timestamp or SELECT CURRENT_TIMESTAMP return
times that are 1 hour ago, which is usually not what you want.

Hope that helps,
At 12:40 AM 2/16/2004 -0500, Michael L. Artz wrote:

>Thanks, that did help to debug the application. I found that my errors
>weren't so random after all ... if I went to a page with a bad query, then
>I would start getting the error.
>
>should throw an error for *both* queries? So I guess I need to issue a
>commit after I do my queries, or else turn autocommit on.

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