Peter Ramm's Oracle performance analysis stuff

This article describes how to analyze blocking locking lock constellations just now in database and also back in history. Especially this includes the identification of database sessions that are initially causing hierarchic blocking lock dependencies. Analyze current blocking lock situation with Panorama Choose menu “DBA general” / “DB locks” / “Current”: Hit button “Blocking DML-Locks” You see a constellation of four sessions blocking each other wile accessing table EMPLOYEE. For each blocking lock you see the waiting session, the blocking session and also the root blocking session which causes the blocking hierarchy. If the blocking session of the lock is also the root cause for the blocking hierarchy than this blocking session is marked orange. That means that you have to clarify this orange sessions problem (probably by killing this session) to release the whole hierarchy of blocked sessions. Via link you can further view detailed info about: blocking and