Re: VLDBA's: gather stats on a large table
- From: Martic Zoran <zoran_martic@xxxxxxxxx>
- To: mark.teehan@xxxxxxxx, "'oracle-l@xxxxxxxxxxxxx'" <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 12 Apr 2005 06:06:40 -0700 (PDT)
Hi Mark,
From what I heard up to now it looks that the
optimizer does not know exactly the partition
operating on, maybe due to the binds or complex
predicates.
This mean only global statistics on
tables/indexes/columns will be used by optimizer.
I agree with Connor about setting statistics if
needed.
But, I will first check do you need to maintain
statistics at all after once gathered.
The question is: do you need at all to collect
statistics again?
If you do not have SQL's using partition statistics
and global statistics are representing correct future
data usage (like you are dropping one partition and
creating another, but data will be similar) then no
need to do global statistics again.
The main thing here is to get the global statistics at
the time when the data distribution will be the best
for your SQL's to perform the best way.
If some are performing bad, then let fixed them by
using Wolfgang Breitling method tuning by cardinality,
so you can set statistics as Connor suggested or do
some additional bad SQL specific statistics gathering.
Regards,
Zoran
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