Re: Question on 19C Optimizer
- From: Jonathan Lewis <jlewisoracle@xxxxxxxxx>
- To: Oracle L <oracle-l@xxxxxxxxxxxxx>
- Date: Sat, 31 Jul 2021 17:51:52 +0100
Yes, object-relational mappers can produce ghastly queries. And if you
need to add hints, you can always create a baseline or use
DBMS_SQLDIAG.CREATE_SQLPATCH.
A problem with baselines et. al. as far as ORMs are concerned is that they
often seem to generate the "same" SQL statement but keep changing the table
and column aliases, so that it's not the same SQL statement, gets a
different sql_id, and therefore doesn't end up as a target for the
baseline/patch/profile/directive.
Regards
Jonathan Lewis
On Sat, 24 Jul 2021 at 18:15, Mladen Gogala <gogala.mladen@xxxxxxxxx> wrote:
When migrating, why not migrate to the latest release? And that is 19.12.
Yes, object-relational mappers can produce ghastly queries. And if you need
to add hints, you can always create a baseline or use
DBMS_SQLDIAG.CREATE_SQLPATCH.
On 7/24/21 7:28 AM, Lok P wrote:
This bug looks too generic and so we are a bit worried as we just can't go
adding leading hints for all queries. But then considering so many
application runs on the below 19.9 versions, wanted to know from experts
here if this occurs only on certain situation? Or we really have to have
patch for this before migrating to 19C?
--
Mladen Gogala
Database Consultant
Tel: (347) 321-1217https://dbwhisperer.wordpress.com
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