Re: Why does a hard parse access data in the table in the query?
- From: Norman Dunbar <oracle@xxxxxxxxxxxxxxx>
- To: "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 7 Feb 2019 14:06:33 +0000
On 07/02/2019 10:19, Norman Dunbar wrote:
I get the feeling I should know this, but it seems to have aged out of
the cache!
Thanks to everyone who said "dynamic sampling" because that's what it
appears to be. I haven't traced it yet, but:
* It was a hard parse;
* Optimizer_dynamic_Sampling = 2 (the default)
Unfortunately, the stats on this database are gathered very frequently.
So the default says to "gather dynamically when one or more of the
tables has no stats" means that I shouldn't be seeing dynamic sampling.
Maybe, because stats go stale pretty quickly on some tables, it's taking
"stale" to mean "none"? I wonder.
Anyway, thanks again, you have been most helpful and hopefully, this
won't age out of cache too soon! :o)
Cheers,
Norm.
--
Norman Dunbar
Dunbar IT Consultants Ltd
Registered address:
27a Lidget Hill
Pudsey
West Yorkshire
United Kingdom
LS28 7LG
Company Number: 05132767
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