DBIx::Timeout

DESCRIPTION

    This module provides a safe method of timing out DBI requests. An unsafe
    method is described in the DBI docs:

       http://search.cpan.org/~timb/DBI/DBI.pm#Signal_Handling_and_Canceling_Operations

    The problem with using POSIX sigaction() is that it relies on unsafe
    signals to work. Unsafe signals are well known to cause instability. For
    example, imagine your DB client code is in the middle of updating some
    global state when the signal arrives. That global state could be left in
    an inconsitent state, just wait for the next time it is needed to cause
    problems. Since this will likely occur far from the cause, and only ocur
    rarely, it can be a very difficult problem to track down.

    Instead, this module:

      - Forks a child process which sleeps for $timeout seconds.

      - Runs your long-running query in the parent process.

      - If the parent process finishes first it kills the child and
        returns.

      - If the child process wakes up it kills the parent's DB thread and
        exits with a code so the parent knows it was timed out.

    NOTE: After this call your database connection may be killed even if no
    timeout occurred. This is due to a race condition - the child may wake
    up just as parent process finishes. Patches addressing this bug are
    welcome. Until this is fixed you should be ready to reconnect after
    call_with_timeout().

DATABASE SUPPORT

    This release supports only MySQL. I would appreciate patches from users
    of other databases. Your patch will need to provide code to kill a
    running query. In MySQL this uses the KILL command.

PREREQUISITES

    DBI 1.49
    Test::More
    Params::Validate

INSTALLATION

To install this module, run the following commands:

    perl Makefile.PL
    make
    make test
    make install

SUPPORT AND DOCUMENTATION

After installing, you can find documentation for this module with the
perldoc command.

    perldoc DBIx::Timeout

COPYRIGHT AND LICENCE

Copyright (C) 2006 Sam Tregar

This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.