NAME

Plack::Middleware::Debug::DBIC::QueryLog - DBIC Query Log and Query Analyzer

SYNOPSIS

Adds a debug panel and querylog object for logging DBIx::Class queries. Has support for Catalyst via a Catalyst::TraitFor::Model::DBIC::Schema::QueryLog compatible trait, Catalyst::TraitFor::Model::DBIC::Schema::QueryLog::AdoptPlack.

    use Plack::Builder;

    my $app = ...; ## Build your Plack App

    builder {
      enable 'Debug', panels =>['DBIC::QueryLog']; 
      $app;
    };

And in you Catalyst application, if you are also using Catalyst::TraitFor::Model::DBIC::Schema::QueryLog::AdoptPlack

    package MyApp::Web::Model::Schema;
    use Moose;
    extends 'Catalyst::Model::DBIC::Schema';

    __PACKAGE__->config({
      schema_class => 'MyApp::Schema',
      traits => ['QueryLog::AdoptPlack'],
      ## .. rest of configuration
    });

DESCRIPTION

DBIx::Class::QueryLog is a tool in the DBIx::Class software ecosystem which benchmarks queries. It lets you log the SQL that DBIx::Class is generating, along with bind variables and timestamps. You can then pass the querylog object to an analyzer (such as DBIx::Class::QueryLog::Analyzer) to generate sorted statistics for all the queries between certain log points.

Query logging in Catalyst is supported for DBIx::Class via a trait for Catalyst::Model::DBIC::Schema called Catalyst::TraitFor::Model::DBIC::Schema::QueryLog. This trait will log all the SQL used by DBIx::Class for a given request cycle. This is very useful since it can help you identify troublesome or bottlenecking queries.

However, Catalyst::TraitFor::Model::DBIC::Schema::QueryLog does not provide out of the box outputting of your analyzed query logs. Usually you need to add a bit of templating work to the bottom of your webpage footer, or dump the output to the logs. We'd like to provide a lower ceremony experience.

Additionally, it would be nice if we could provide this functionality for all Plack based applications, not just Catalyst. Ideally we'd play nice with Plack::Middleware::Debug so that the table of our querylog would appear as a neat Plack based Debug panel. This bit of middleware provides that function.

Basically we create a new instance of DBIx::Class::QueryLog and place it into $env->{'plack.middleware.dbic.querylog'} so that it is accessible by all applications running inside of Plack. You need to 'tell' your application's instance of DBIx::Class to use this $env key and make sure you set DBIx::Class's debug object correctly:

    use Plack::Middleware::Debug::DBIC::QueryLog;
    my $querylog = $env->{+Plack::Middleware::Debug::DBIC::QueryLog::PSGI_KEY};
    my $cloned_schema = $schema->clone;
    $cloned_schema->storage->debug(1);
    $cloned_schema->storage->debugobj($querylog);

That way when you view the debug panel, we have SQL to review.

There's an application in '/example' you can review for help. However, if you are using Catalyst and a modern Catalyst::Model::DBIC::Schema you can use the trait Catalyst::TraitFor::Model::DBIC::Schema::QueryLog::AdoptPlack, which is compatible with Catalyst::TraitFor::Model::DBIC::Schema::QueryLog.

If you want a querylog but don't want or need the Plack debug panel, you should take a look at Plack::Middleware::DBIC::QueryLog.

See the "SYNOPSIS" example for more details.

OPTIONS

This debug panel defines the following options.

querylog_class

This is the class which is used to build the querylog unless one is already defined. It defaults to DBIx::Class::QueryLog. You should probably leave this alone unless you need to subclass or augment DBIx::Class::QueryLog.

If the class name you pass has not already been included (via use or require) we will automatically try to require it.

querylog_args

Takes a HashRef which is passed to DBIx::Class::QueryLog at construction.

SEE ALSO

Plack::Middleware::Debug, Catalyst::TraitFor::Model::DBIC::Schema::QueryLog, Catalyst::Model::DBIC::Schema, Catalyst::TraitFor::Model::DBIC::Schema::QueryLog::AdoptPlack

AUTHOR

John Napiorkowski, <jjnapiork@cpan.org>

COPYRIGHT & LICENSE

Copyright 2011 John Napiorkowski

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

cpanm Plack::Middleware::Debug::DBIC::QueryLog

perl -MCPAN -e shell
install Plack::Middleware::Debug::DBIC::QueryLog