ASH

Oracle ASH SQL_PLAN_LINE_ID in adaptive plans

There are several methods to find out where time is spent in an execution plan of a query running in an Oracle database. Classical methods like SQL Trace and running a formatter tool like tkprof on the raw trace, or(…)

Drilling down the pgSentinel Active Session History

By Franck Pachot . In pgSentinel: the sampling approach for PostgreSQL I mentioned that one of the advantages of the ASH approach is the ability to drill down from an overview of the database activity,(…)

pgSentinel: the sampling approach for PostgreSQL

By Franck Pachot . Here is the first test I did with the beta of pgSentinel. This Active Session History sampling is a new approach to Postgres tuning. For people coming from Oracle, this is something(…)

PGIO, PG_STAT_ACTIVITY and PG_STAT_STATEMENTS

By Franck Pachot . For an Oracle DBA, we are used to join active sessions (from V$SESSION where status='ACTIVE) with active statements (from V$SQL where users_executing>0) on the SQL_ID. V$ACTIVE_SESSION_HISTORY also displays the TOP_LEVEL_SQL_ID to get the entrypoint of the(…)

Execution Plan with ASH

By Franck Pachot . Here is a query I use when I'm on a system that has Diagnostic Pack (ASH) but no tuning Pack (SQL Monitor). It displays the execution plan with dbms_xplan.display_cursor and adds the % of ASH samples(…)

AWR when ASH CPU >> DB CPU

By Franck Pachot . I'll present How to read an AWR report next month at UKOUG TECH15 and the first recommendation after checking Average Active Sessions is to verify that we are not in a CPU starvation situation. Here is(…)