RE: Batch and OLTP at the same time : Mission possible ?
- From: "GUILLAUMIN Bert Ext ROSI/SI CLIENT" <bguillaumin.ext@xxxxxxxxxxxxxxxxx>
- To: "'David Aldridge'" <david@xxxxxxxxxxxxxxxxxx>, "'Daniel Fink'" <danielwfink@xxxxxxxxx>
- Date: Fri, 28 Apr 2006 18:02:36 +0200
David,
I totally do agree that parallelism has to go(I said so in my first mail).
I must say that excessive CPU usage is not what I fear the most(since the batch
without parallelism would use at most 1 CPU and we have 12). But thanks for the
tip if problems occurs on that level I'll have and idea of what i may use.
My greatest fear is contention in regard to tables and indexes.
Daniel : I totally understand what you say and that's the reason why I advised
against this solution. My point of view hasn't prevailed so now I have to do it
this way.
Now my idea of record by record solution seems to be endorsed by Tom Kyte in 8i
(see
http://asktom.oracle.com/pls/ask/f?p=4950:8:18066575999822505476::NO::F4950_P8_DISPLAYID,F4950_P8CRITERIA:4343304784432)
For him if you're in OLTP mode, you do things the OLTP way.
But I wonder whether in 9i there is no other solution since i fear it would be
very slow(even slow enough to be unable to complete in time).
Regards,
Bertrand Guillaumin
-----Message d'origine-----
De : David Aldridge [mailto:david@xxxxxxxxxxxxxxxxxx]
Envoyé : vendredi 28 avril 2006 16:51
À : GUILLAUMIN Bert Ext ROSI/SI CLIENT
Cc : 'Oracle-L Freelists'
Objet : Re: Batch and OLTP at the same time : Mission possible ?
The parallelism on the OLTP tables almost certainly has to go --- the
query coordinator kicks off a segment-level checkpoint before the query
slaves start reading (thx JL), so that could be a significant impact on
users.
You might like to look at Resource Manager to control the CPU impact of
this job also, if the machine gets hard-pressed.
Row-by-row sounds like a Bad Thing, especially if you can control the
impact of the batch job with RM
-----Message d'origine-----
De : Daniel Fink [mailto:danielwfink@xxxxxxxxx]
Envoyé : vendredi 28 avril 2006 16:16
À : GUILLAUMIN Bert Ext ROSI/SI CLIENT; 'Oracle-L Freelists'
Objet : Re: Batch and OLTP at the same time : Mission possible ?
Bertrand,
One thing to consider is the impact of these processes on queries. If a query
is reading the data (or other data in the same block) you are updating, there
might be a significant performance penalty. I have seen reporting queries run
up to 42 times slower when they are generating read consistent views of the
data because a poorly designed and coded update process is running at the same
time.
Regards,
Daniel Fink
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