Parallel Distributed CTAS
- From: Laimutis.Nedzinskas@xxxxxx
- To: oracle-l@xxxxxxxxxxxxx
- Date: Fri, 4 Feb 2011 14:03:36 +0200
Hi,
Giving up on that one:
create table TD
parallel 2
as select /*+parallel(t 2)*/* from TS@SRCDB t
/
takes twice the time compared to serial execution...
I have tested non-distributed Parallel CTAS vs serial CTAS both on source
and destination databases. Parallel works faster just as it is advertised.
That kind of proves that isolated database, storage, hardware is not an
issue.
Looking into statistics, destination session reports basically twice the
number "physical write bytes" than the same serial execution, i.e. 2G.
Each one of 2 parallel processes report 1G.
The table is roughly 1G size.
If this is a pecularity of how oracle tracks parallel execution statistics
I am not sure.
For me it looks like some issue with how oracle internally processes
distributed parallel CTAS.
Any ideas are wellcomed.
Brgds, Laimis N
Thank you in advance, Liamis
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