Re: interpreting statspack reports ( PX Deq )

Indeed these are parallel query events. With respect to the database they can be ignored as "idle events". If parallel query is a performance issue for you, approach it as a sql tuning exercise instead of a database tuning issue.

Statspack has a table you can modify to filter these out. Log in as perstat or whoever owns the statspack schema and list the tables. One of them has the word "idle" in it and will be the table to change. Look at the rows and insert the text of the events - precisely, as it is case sensitive.

The only way to fully comprehend the events reported in statspack is to thoroughly understand the database itself. The best doc for that purpose is still the concepts manual.

• ricky

john wrote:
>
> Oracle 8i ( 8.1.7.0.0 )
> Solaris 8
> __NO__ Parallel Server but am using Parallel Query
>
> I have at the top 5 of the wait events the following:
>
> Top 5 Wait Events
> ~~~~~~~~~~~~~~~~~ Wait
> % Total
> Event Waits Time (cs)
> Wt Time
> -------------------------------------------- ------------ ------------
> -------
> PX Deq Credit: send blkd 334,105 176,389
> 37.10
> PX Deq: Execution Msg 35,860 57,729
> 12.14
> PX Deq: Table Q Normal 865,976 50,065
> 10.53
> PX Deq: Execute Reply 22,596 46,401
> 9.76
> db file scattered read 285,813 44,901
> 9.44
> -------------------------------------------------------------
>
> However, looking at the Wait Events descriptions in the Oracle8i
> Reference manual, I cannot find a description for the first 4 wait
> events above. ( I assume here that PX means parallel execution ). The
> only wait events listed on the manuals for parallel execution are:
>
> parallel execution create server
> parallel execution dequeue wait
> parallel execution qref latch
> parallel execution server shutdown
> parallel execution signal server
>
> What are these event names and what do they mean??
>
> Also, I have the following latches with a high ratio:
>
> Pct Avg
> Pct
> Get Get Slps
> NoWait NoWait
> Latch Name Requests Miss /Miss
> Requests Miss
> ----------------------------- -------------- ------ ------
> ------------ ------
> parallel query alloc buffer 24,010 3.6 0.0
> 0
> parallel query stats 3,703 26.0 0.2
> 0
>
> ... but what do these 2 latch name means? and their corresponding
> figures?
>
> Is there a full / comprehensive list of
>
> 1) event names and their meanings ( the ones I mentioned above are not
> in Oracle8i Reference )
>
> 2) latch names and their meanings
>
> Does anyone also know of a doc to fully interpret reports generated
> from statspack?
>
> Thanks
>
> John
Received on Thu Jun 13 2002 - 21:29:16 CDT