Re: Expensive SQL

From: Mladen Gogala <no_at_email.here.invalid>
Date: Tue, 23 Aug 2011 18:11:09 +0000 (UTC)
Message-ID: <pan.2011.08.23.18.11.08_at_email.here.invalid>

On Tue, 23 Aug 2011 09:02:46 -0700, dombrooks wrote:

> Yep - I did just post some additional information but it's not appeared
> yet.
>
> Although the headline description of the bug mentioned baseline capture,
> it's very much baseline usage that is also the problem.
>
> I assume you must have some baselined statements in
> dba_sql_plan_baselines.
>
> The performance bug concerns full table scans on recursive merges into
> sqlobj$, sqlobj$data and sqlobj$auxdata.
>
> When you execute a baselined statement (even if capture is off), you get
> at least one lookup on SQLOBJ$ and SQLOBJ$AUXDATA plus a MERGE into the
> same objects to update the baseline metadata on those statements.
>
> Post patch for 11715191 you still get these statements, but they've been
> hinted with an INDEX hint
>
> Cheers.
> Dominic

That patch will probably make it into the October PSU. I am reluctant to apply one-off patches. I will rather turn off baselines altogether.

-- 
http://mgogala.byethost5.com

Received on Tue Aug 23 2011 - 13:11:09 CDT