Re: improve cardinality estimation
From: Mladen Gogala <gogala.mladen_at_gmail.com>
Date: Wed, 28 Oct 2020 13:22:58 -0400
Message-ID: <ff252a03c5f8cf860fb9537903fc4ee20955496e.camel_at_gmail.com>
Date: Wed, 28 Oct 2020 13:22:58 -0400
Message-ID: <ff252a03c5f8cf860fb9537903fc4ee20955496e.camel_at_gmail.com>
On Wed, 2020-10-28 at 07:08 +0200, Laurentiu Oprea wrote:
> Dynamic sampling 11 was the nightmare until not so long. Due to a bug
> the automatic determined value was 11. It was generating a parsing
> time of over 5 minutes to parallel queries and when downgrade was
> happening due to various reasons I could see even 30 minutes of
> parsing (there were even extreme cases of 2-3 hours).
There were several horrible bugs, one of them caused excessive latching
in Oracle 12.1. I assume that everyone is on 19.9. I might be wrong
there, however unlikely that seems.
Regards
-- Mladen Gogala Database Consultant Tel: (347) 321-1217 -- http://www.freelists.org/webpage/oracle-lReceived on Wed Oct 28 2020 - 18:22:58 CET