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.