Re: "snapshot too old" and undo_retention
- From: Jared Still <jkstill@xxxxxxxxx>
- To: roger_xu@xxxxxxxxxxx
- Date: Mon, 3 Oct 2005 09:40:59 -0700
On 9/30/05, Roger Xu <roger_xu@xxxxxxxxxxx> wrote:
> Anybody partition this table? How? Thanks.
SAP has notes on partitioning.
Before springing for partitioning, (10k U.S. per CPU) you may want
to determine if partitioning is worth the money and time.
I'm not familiar with BSIS table, but we have a similarly large
table in our implementation, the COEP table.
Was 800m rows, now down to about 400m rows after archiving.
(SAP transaction archiving)
These large tables can sometimes be a performance problem, but that
may be only indirectly related to the size of the table.
There is a transaction for which we run a nightly job, and it was performing
very poorly. If an old transaction that is no longer needed is not marked
for deletion, this SAP job will examine the transaction, exploding BOMs
and everything else along the way.
Once this business problem was corrected, performance was fine.
Partitioning would be useful from a storage perspective in this case
if we could create a useful partition key that would let us drop a
partition after archiving.
As it is, we are just going to rebuild the table. Archiving will be
regularly run to clean it up, and the existing space in the table
reused.
If you have an 4/8 way server, partitioning may not have a good ROI.
--
Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist
--
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