Summary: SQLT is a tool that collects comprehensive information on all aspects of a SQL performance problem. SQL tuning experts know that EXPLAIN PLAN is only the proverbial tip of the iceberg but the fact is not well recognized by the Oracle database community, so much evangelization is necessary.
I remember the time I was trying to solve a production problem a long time ago. I did not have any tools but I was good at writing queries against the Oracle data dictionary. How does one find the PID of an Oracle dedicated server process? Try something like this:
select spid from v$process where addr=(select saddr from v$session where sid = '&sid')
My boss was not amused.
After the incident, he got me a license for Toad.
Writing queries against the data dictionary is macho but it is not efficient.
Tools are in.
Carlos Sierra spent 17 years in the SQL performance group of Oracle Support. He couldn’t move a mountain nor pull down a big oak tree. But Carlos Sierra became a mighty big man by putting all the knowledge he gained during that time into a wonderful tool called “SQLT.”(read more)
A SQLT report has all kinds of pertinent information including—to name just a few—optimizer settings, indexes, statistics, plan history, and view definitions. However, sometimes a SQLT report is not enough to solve a SQL performance problem.(read more)
Previous installment: Day Three: Just a Mess Without a Clue
I know a funny little man,
As quiet as a mouse,
Who does the mischief that is done
In everybody’s house!
There’s no one ever sees his face,
And yet we all agree
That every plate we break was cracked
By Mr. Nobody.
P.O.I.S.E.D. is an acronym for a six-step performance tuning method; it stands for Problem, Observation, Interpretation, Solution, Execution, and Documentation. Every problem-solving exercise has these six stages, whether the exercise takes six minutes or six weeks.(read more)
SQLT adoption has been limited even though it is the best tool for investigating SQL performance: It is only available as a download from Oracle Support. It creates tables and PL/SQL procedures in the database. It does not support Statspack, only AWR. (read more)
In his fifteen years with Oracle Support, Carlos Sierra created and perfected a tool called SQLTXPLAIN (SQL Tuning and Explain Plan; SQLT for short) for SQL performance investigations. SQLT collects all the information that could possibly be required to investigate SQL performance including environment information, execution plan history, statistics history (system statistics, table statistics, index statistics), and object definitions.(read more)
I finally have a moment to look into my “hacked” SQLT XPRECT/XTRACT runs and see if the changes I made were enough to run properly with the AWR Warehouse.
The answer is yes and no… and maybe “it depends”…