jepri has asked for the wisdom of the Perl Monks concerning the following question:

I had been using Tie::DBI in a CGI app I was writing. All was working nicely, but as the project progressed, the script starting segfaulting randomly, usually near a database access (I found it difficult to get debugging information near the the point where it segfaulted. Repeated the query usually worked.

Then I started concurrency testing, and discovered to my horror that I was getting consistent segfaults while two or more people were accessing the site at the same time.

At this point I am well on the way to converting my scripts back to 'plain' DBI, so I am not looking for an answer as such, just wondering if there is some piece of knowledge that I have overlooked.

I haven't submitted a bug report because I have no idea what could be going wrong.

____________________
Jeremy
I didn't believe in evil until I dated it.

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Re: Serious concurrency issues with Tie::DBI
by Stegalex (Chaplain) on Oct 06, 2001 at 21:22 UTC
    Pardon my ignorance, but are you using a DBMS? If so, please tell us what it is (including version) along with info about h/w, os, versions for everything.
[reply]
      I wasn't able to find out what a DBMS is (DataBase Management System?), but I was using PostGreSQL 6.5 with Perl 5.3 (5.005.3). I can't recall the version of Tie::DBI, but I installed it in March, so it would be 0.8x.

      Oh yeah, OS. Debian potato, kernel 2.2.18, running on a P-one hundred and something with 32 MB ram.

      The author of Tie::DBI does state in the docs that DBD::Pg is broken when dealing with NULL values, but DBI with DBD::Pg seems to cope fine so I don't know what's wrong there.

      ____________________
      Jeremy
      I didn't believe in evil until I dated it.

[reply]
        Hmmm.

        Are you segfaulting under Apache or are you running your process from the command line or cron? If you are segfaulting under Apache and you are using mod_perl, you should upgrade mod_perl to v 1.24. Earlier versions have serious problems.

        Also, Is there a reason you have not yet upgraded your Perl to 5.6?

        My generic advice is to check the CPAN and upgrade your modules (such as DBD:Pg, DBI, mod_perl, and any others).

        Let me know if you get any joy from this.
[reply]

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