Re: SQL Profile and baseline

From: Mladen Gogala <gogala.mladen_at_gmail.com>
Date: Tue, 1 Feb 2022 19:20:27 -0500
Message-ID: <d2553e5e-90c9-3681-87ea-825dec4b977f_at_gmail.com>

Hi,

As a general guideline, once a SQL profile provides an optimal execution plan for a SQL, is it okay to create a baseline for that SQL and then drop the SQL Profile? The DB version is 11.2.0.4. Any feedback will be appreciated.

 

Thanks,

Amir

Hi Amir,

Both baselines and profiles are essentially the same thing: a bunch of hints. In my experience, profiles provide more stable and overall better mechanism for achieving plan stability. Baselines are poor man's profiles. However, if you want to nail the plan to the wall, you can also create an outline, which is an actual execution plan which doesn't change or evolve but stays the same forever and ever, until "drop database" takes it apart. Outlines are deprecated but still supported. However, I wouldn't advise using outlines precisely because their inability to evolve.

-- 
Mladen Gogala
Database Consultant
Tel: (347) 321-1217
https://dbwhisperer.wordpress.com

-- http://www.freelists.org/webpage/oracle-l Received on Wed Feb 02 2022 - 01:20:27 CET