Editing Kieker (section)

==How does it work?==

For EPrints, Kieker uses a PERL module called Sub::WrapPackages which basically allows user to define global wrappers for internal calls. It is possible to restrict which modules are wrapped: for instance, you may want to only profile the database layer, in which case you probably want to wrap EPrints::Database and EPrints::Database::MySQL. The EPrints/Kieker extensions (https://github.com/eprints/epkieker) make it easy to set this up.

When Kieker is enabled it will trap any selected internal calls and will send some information to a queueing system. The data sent will contain a high-precision timestamp, the name of the module, of the function etc. Traditionally Kieker uses JMS as a queueing system but we integrated it with memcached which is a popular, easy-to-install server-wide caching system.

Once you're happy with the profiling, you can disable kieker and retrieve the data from the queue. Then you may use Kieker's built-in tools to generate all sorts of graphs.