Re: Plan changed After creating profile

Adric,

Useful warning.

Somewhere I have a note that points out that when you have an SQL P,lan Baseline in place the first thing the optimizer does is optimize the query without looking at the Baseline; so if you've got a query that takes a long time to optimize a Basline won't address that part of the problem and a "cunning plan" is to create the Baseline that works well, then convert it to an SQL Patch (with a couple of calls to the relevant package).

Regards
Jonathan Lewis

On Thu, 30 Sept 2021 at 14:52, Adric Norris <landstander668_at_gmail.com> wrote:

> Generally people seem to find SQL Plan Baslines more stable than SQL
>> Profiles (but I can't quantify that, I only have anecdotal evidence) - so
>> if you've generated a SQL Profile it might be a good idea to generate an
>> SQL Plan Basline after running the query, accept it and fix it, then delete
>> the profile.
>
>
> I've seen multiple situations where the plan fixed by the baseline can't
> be reproduced (within the time constraints the optimizer is faced with)
> unless the profile is present and enabled. So there's a chance that the
> profile will have to be left in place.
>
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