Re: PX Deq Credit: send blkd
- From: "Christian Antognini" <Christian.Antognini@xxxxxxxxxxxx>
- To: "Martin Klier" <usn@xxxxxxxxx>
- Date: Sun, 21 Sep 2008 10:27:17 +0200
Hi Martin
> 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.
It would be interesting to see the execution plan. In fact, it clearly
shows whether the DDL part of the statement should be parallelized or
not.
> How can I make it parallel on WRITING side of the statement?
Let's try something else... In my book (at page 506 for the people
having it handy) I wrote the following:
"A CTAS statement is composed of two operations that process data: the
query used to retrieve data from the source tables and the insert into
the target table. Each part can be executed either serially or in
parallel independently of the other. However, if parallel processing is
used, it is common to parallelize both operations."
Then I show three execution plans illustrating the three cases:
- Parallelization of insert only
- Parallelization of query only
- Parallelization of both operations
To produce the execution plans used for the book I used the script
px_ddl.sql which is available along with all other scripts distributed
with the book under http://antognini.ch/top/downloadable-files/. So, I
suggest you to download and execute it. With that script I had no
problem to reproduce the expected behavior whenever I run it. If it
doesn't work, I would like to see the list of all initialization
parameters that are *not* set to the default.
HTH
Chris Antognini
Troubleshooting Oracle Performance, Apress 2008
http://top.antognini.ch
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