DBI::ProfileDumper::Apache(3)				User Contributed Perl Documentation			     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

       (If you're using mod_perl2, see "When using mod_perl2" for some additional notes.)

       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 /path/to/your/apache/logs/dbi.prof.*

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

       The DBI will look after loading and using the module when the first DBI handle is created.

       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, and DBI::Profile for full details of the DBI's profiling mechanism.

   WRITING PROFILE DATA
       The profile data files will be written to your Apache log directory by default.

       The user that the httpd processes run as will need write access to the directory.  So, for example, if you're running the child httpds as
       user 'nobody' and using chronolog to write to the logs directory, then you'll need to change the default.

       You can change the destination directory either by specifying a "Dir" value when creating the profile (like "File" in the
       DBI::ProfileDumper docs), or you can use the "DBI_PROFILE_APACHE_LOG_DIR" env var to change that. For example:

	 PerlSetEnv DBI_PROFILE_APACHE_LOG_DIR /server_root/logs

       When using mod_perl2

       Under mod_perl2 you'll need to either set the "DBI_PROFILE_APACHE_LOG_DIR" env var, or enable the mod_perl2 "GlobalRequest" option, like
       this:

	 PerlOptions +GlobalRequest

       to the global config section you're about test with DBI::ProfileDumper::Apache.	If you don't do one of those then 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

       Naming the files

       The default file name is inherited from DBI::ProfileDumper via the filename() method, but DBI::ProfileDumper::Apache appends the parent pid
       and the current pid, separated by dots, to that name.

       Silencing the log

       By default a message is written to STDERR (i.e., the apache error_log file) when flush_to_disk() is called (either explicitly, or
       implicitly via DESTROY).

       That's usually very useful. If you don't want the log message you can silence it by setting the "Quiet" attribute true.

	 PerlSetEnv DBI_PROFILE 2/DBI::ProfileDumper::Apache/Quiet:1

	 $dbh->{Profile} = "!Statement/DBI::ProfileDumper/Quiet:1";

	 $dbh->{Profile} = DBI::ProfileDumper->new(
	     Path => [ '!Statement' ]
	     Quiet => 1
	 );

   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.2604.2619

       Now you can use dbiprof to examine the data:

	 dbiprof /usr/local/apache/logs/dbi.prof.2604.*

       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.

OTHER ISSUES

   Memory usage
       DBI::Profile can use a lot of memory for very active applications because it collects profiling data in memory for each distinct query run.
       Calling "flush_to_disk()" will write the current data to disk and free the memory it's using. For example:

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

       or, rather than flush every time, you could flush less often:

	 $dbh->{Profile}->flush_to_disk()
	   if $dbh->{Profile} and ++$i % 100;

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.

perl v5.16.2							    2010-06-08					     DBI::ProfileDumper::Apache(3)