Re: is rebuilding indexes necessary after import?
- From: Jaffar_DBA <sjaffarhussain@xxxxxxxxx>
- To: Jeremiah Wilton <jwilton@xxxxxxxxxxxxx>
- Date: Wed, 22 Dec 2004 10:57:51 +0300
The reason, why I am asking question is, recently I have migrated my
warehouse database from 8i to 9i on AIX machine using export/import.
The query which was taking 10 - 20 mins. was taking hours to finish I
tried looking into execution plan, taking 10046 event and taking
statspack. Query was reading index properly and I was going crazy. I
just rebuild the index and it when like before. I realized at that
time that we might have to rebuild indexes back once importing them.
But, technically, when you import indexes, it actually use create
idnex command and created indexes. So, why there was a problem with my
index at the point of time was a question mark. I face a lot of
performance degration after migration 8i to 9i on AIX. Then after
applying patch set 9.2.0.5, the situation come acceptable as oracle
says they have fixed a lot of optimizer bugs in 9.2.0.5.
JAFFAR
On Tue, 21 Dec 2004 23:43:31 -0800 (PST), Jeremiah Wilton
<jwilton@xxxxxxxxxxxxx> wrote:
> On Wed, 22 Dec 2004, Jaffar_DBA wrote:
>
> > My question is, do we really need to rebuild/recreate indexes after
> > importing them into another database?
>
> Probably the reason they recommend this is that they hope you will
> import without indexes, then build them in some more efficient way
> (parallel, unrecoverable) with the export completed, saving yourself
> time.
>
> Also, your nickname for this list - Active DBA (from the To: header) -
> is this is contrast to Lazy DBA? If so I like the distinction!
>
> --
> Jeremiah Wilton
> Independent Oracle Professional
> Oracle Certified Master
> Disaster Recovery - Seminars - Technical Interviews
> http://www.speakeasy.net/~jwilton
>
--
Best Regards,
Jaffar, OCP DBA
Banque Saudi Fransi
Saudi Arabia
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