Re: PX Deq Credit: send blkd

Have you tried

alter session enable parallel ddl;

Cheers,

Ian

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  |       Subject:  Re: PX Deq Credit: send blkd                                                                 |
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Hi again.

I've got still the same problem, but I tried to simplify it, reduce it to the essentials.

I tried to
CREATE TABLE2 TEST PARALLEL 32 AS SELECT * FROM TEST; It works, but the 32 parallel processes are only query processes, there is only ONE writing process. Due to that, all parallel query processes are waiting with "PX Deq Credit: send blkd"

How can I make it parallel on WRITING side of the statement?

The bahaviour is similar or same if I do an INSERT /*+ APPEND PARALLEL(TEST2,32) */ INTO TEST2 SELECT * FROM TEST; when both sides are identically partitioned (4 partitions).

Any further clues? Or known no-gos?

Thanks a lot,
Martin

Martin Klier schrieb:
> I've got massive wait events named "PX Deq Credit: send blkd". As far as
> I know, that's a parallel query issue, a producer is faster then the
> consumer. But thats a textbook explanantion I simply don't understand.
> The obvious option, to increase PARALLEL_EXECUTION_MESSAGE_SIZE, does
> not fit since it's set to the (x86_64) architecture's maximum, 64k.
>
> The system is rather capable, and CPU load is less than 30%, disk IO
> around 100MB/s, the underlying ASM diskgroups have been successfully
> tested with nearly 1GB/s.
>
> The query in question is a huge MERGE statement with APPEND PARALLEL
> hints, a little abstracted form here:
> ...

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