Re: PX Deq Credit: send blkd

  • From: Martin Klier <usn@xxxxxxxxx>
  • To: Claudia Zeiler <czeiler@xxxxxxxxxx>, oracle-l@xxxxxxxxxxxxx
  • Date: Fri, 29 Aug 2008 20:29:52 +0200

Hi Claudia,

Claudia Zeiler schrieb:
> Do you know how many parallel processes are trying to run?  We had this wait 
> event.  
> It turned out that we were trying to create indexes as 'parallel'
without specifying the degree.
>Oracle defaulted to 57 processes, and we had a FIGHT on our hands.  27
actually managed to run, and the others
> waited on the PX Deq Credit: send blkd wait event.  Maybe you too have more 
> parallllllel ism than you intended.

There are many parallel hints in the statement, I guess about 30 :)
The system itself has 114 parallel processes (ora_p*) ATM.

One explanation I'd consider as possible is, that the MERGE itself
spawns less p-processes than the sub-selects, so that the select's
p-processes (the producers) are too fast for the merge (consumer).

But this is a guess, and it would ge great to see some reliable method
to track this issue down :)


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