[TYPO3-core] FYI24: Add feature #11708: Optimize database queries to session tables

[Oliver Hader]

This is an SVN patch request that will be committed to SVN after 24
hours if nobody objects.

Type: Feature

Bugtracker references:
http://bugs.typo3.org/view.php?id=11708

Branch: Trunk

Problem:
Database queries to session tables will be performed each request when a
frontend or backend user is logged in. To determine whether a session
has expired in between always the "ses_tstamp" field is evalated with a
proper index.

Solution:
Define an index in the field ses_tstamp for the tables be_sessions and
fe_session.

Rewrite the condition to check against expired sessions to only use
precalculated values and make use of the new index (only used in the
backend module to show online users).

olly
-- 
Oliver Hader
TYPO3 Release Manager 4.3