NAME
    RT::Extension::Log::MemoryUsage - log information about memory used by
    RT processes

SYNOPSIS
        # in RT site config

        # register plugins
        Set( @Plugins, qw(
            ... other plugins ...
            RT::Extension::Log::MemoryUsage
        ));
        Set(@MasonParameters,
            plugins => [qw(RT::Extension::Log::MemoryUsage::MPL)],
        );

        # setup logging to see messages
        Set( $LogToScreen, 'info');
        # or
        Set( $LogToSyslog, 'info');

DESCRIPTION
    This extension helps identify requests that cause a memory usage spikes.

    RT is a big application with many modules, extensions and different ways
    to run system. As well, there are tons of ways to screw up memory usage.
    It's hard to detect memory leaks and not only them, but just places in
    code that like to eat lots of memory. This extension reports memory
    usage changes after each request to the server. Unix `ps` command is
    used to get this information.

INSTALLATION
        perl Makefile.PL
        make
        make install

    Change RT site config according to "SYNOPSIS", restart server.

RESULTS
    When RT handles a request this plugin logs two messages. Before the
    request and after. Something like:

        memory after '/index.html' =>
            pid: 25956; rss: 55380 (+20); rsz: 55380 (+20);
            vsz: 129168 (+144); tsiz: 0; %mem: 2.6;
        memory before '/index.html' =>
            pid: 25956; rss: 55360 (-20); rsz: 55360 (-20);
            vsz: 129024 (-144); tsiz: 0; %mem: 2.6;

    Message issued before request shows change in memory usage since
    previouse request to this process. Usually it shows negative numbers,
    except for request after first touch of a component. Negative numbers is
    a result of taking sample a little bit earlier after request when some
    memory is not freed yet, but it is free before next request. As you can
    see above in example all additional memory was freed between requests.

    When a page requested for the first time then usually numbers don't
    match. This happens cuz perl have to compile new code and that code
    stays in the system for the whole time.

    However, if you have a page X and constantly next request doesn't
    reclaim all memory before then you have a memory leak.

AUTHOR
    Ruslan Zakirov <ruz@bestpractical.com>

LICENSE
    Under the same terms as perl itself.

