DBI::ProfileDumper::Apache(3)

NAME
DBI::ProfileDumper::Apache - capture DBI profiling data from Apache/mod_perl

SYNOPSIS
Add this line to your httpd.conf:

  PerlSetEnv DBI_PROFILE 2/DBI::ProfileDumper::Apache

Under mod_perl2 RC5+ you'll need to also add:

  PerlSetEnv DBI_PROFILE_APACHE_LOG_DIR /server_root/logs

OR add

  PerlOptions +GlobalRequest

to the gobal config section you're about test with DBI::ProfileDumper::Apache. If you don't do this, you'll see messages in your error_log similar to:

  DBI::ProfileDumper::Apache on_destroy failed: Global $r object is not available. Set:
    PerlOptions +GlobalRequest in httpd.conf at ..../DBI/ProfileDumper/Apache.pm line 144

Then restart your server. Access the code you wish to test using a web browser, then shutdown your server. This will create a set of dbi.prof.* files in your Apache log directory. Get a profiling report with dbiprof:

  dbiprof /usr/local/apache/logs/dbi.prof.*

When you're ready to perform another profiling run, delete the old files

  rm /usr/local/apache/logs/dbi.prof.*

and start again.

DESCRIPTION
This module interfaces DBI::ProfileDumper to Apache/mod_perl. Using this module you can collect profiling data from mod_perl applications. It works by creating a DBI::ProfileDumper data file for each Apache process. These files are created in your Apache log directory. You can then use dbiprof to analyze the profile files.

USAGE

  LOADING THE MODULE
The easiest way to use this module is just to set the DBI_PROFILE environment variable in your httpd.conf:

  PerlSetEnv DBI_PROFILE 2/DBI::ProfileDumper::Apache

If you want to use one of DBI::Profile's other Path settings, you can use a string like:

  PerlSetEnv DBI_PROFILE 2/DBI::ProfileDumper::Apache

It's also possible to use this module by setting the Profile attribute of any DBI handle:

  $dbh->{Profile} = "2/DBI::ProfileDumper::Apache";

See DBI::ProfileDumper for more possibilities.

  GATHERING PROFILE DATA
Once you have the module loaded, use your application as you normally would. Stop the webserver when your tests are complete. Profile data files will be produced when Apache exits and you'll see something like this in your error_log:

  DBI::ProfileDumper::Apache writing to /usr/local/apache/logs/dbi.prof.2619

Now you can use dbiprof to examine the data:

  dbiprof /usr/local/apache/logs/dbi.prof.*

By passing dbiprof a list of all generated files, dbiprof will automatically merge them into one result set. You can also pass dbiprof sorting and querying options, see dbiprof for details.

  CLEANING UP
Once you've made some code changes, you're ready to start again. First, delete the old profile data files:

  rm /usr/local/apache/logs/dbi.prof.*

Then restart your server and get back to work.

MEMORY USAGE
DBI::Profile can use a lot of memory for very active applications. It collects profiling data in memory for each distinct query your application runs. You can avoid this problem with a call like this:

  $dbh->{Profile}->flush_to_disk() if $dbh->{Profile};

Calling "flush_to_disk()" will clear out the profile data and write it to disk. Put this someplace where it will run on every request, like a CleanupHandler, and your memory troubles should go away. Well, at least the ones caused by DBI::Profile anyway.

AUTHOR
Sam Tregar <sam@tregar.com>

COPYRIGHT AND LICENSE
Copyright (C) 2002 Sam Tregar

This program is free software; you can redistribute it and/or modify it under the same terms as Perl 5 itself.