Re: Guidelines for avoid Bind Variable Peeking behavior

From: Roberto Veiga <roberto_veiga_at_yahoo.com>
Date: Mon, 1 Jun 2009 08:21:37 -0700 (PDT)
Message-ID: <119789.94308.qm_at_web35601.mail.mud.yahoo.com>



Yes, this is an option but I need to review all my code to change this. Is not an easy solution, but it is possible to be implement.
 
  • Em dom, 31/5/09, troach_at_gmail.com <troach_at_gmail.com> escreveu:

De: troach_at_gmail.com <troach_at_gmail.com> Assunto: Re: Guidelines for avoid Bind Variable Peeking behavior Para: roberto_veiga_at_yahoo.com, oracle-l_at_freelists.org Data: Domingo, 31 de Maio de 2009, 11:19

Have you considered not using binds for certain statements? How many times is the query executed?

Sent from my Verizon Wireless BlackBerry

From: Roberto Veiga
Date: Sun, 31 May 2009 07:14:16 -0700 (PDT) To: <oracle-l_at_freelists.org>
Subject: Guidelines for avoid Bind Variable Peeking behavior

I am facing a lot of problems with bind variables because the access plan is changing and a critical performance problem occurs.(I have already posted a question "Histogram worthwhile" here at Oracle-l). I am suffering the "bind variable peeking" behavior.
 

My customer is very disapointed about this "feature" of Oracle and he is asking me what to do to avoid this behavior.
 

We have already tried to remove histograms and the situation become worse.
 

I have proposed him to focus on the most critical process and put some hints to freeze the plan.
 

But the processes work with a lot of procedures with a lot of statements. So I need to define a method to focus only in the queries with most change to have this problem.
 

I can use Stored Outlines (Plan Stability) but I have a *lot of* queries and I need a fast way to configure those queries.
 

I am thinking use Sql Profiles but I need a fast way to use this with a lot of queries and I really dont know if this approach is going to resolve the changing plan problem.
 

I am thinking using this points to focus only in a few potential problem queries:
 

-Statements with Bind Variables
-Columns with Skewed distribution
-Statements with more than 5 tables join
-Tables with many rows (500k or more)
-Access plan using Hash Join

 

Is this a good approach to identify queries that can have the plan changed?
 

We are having a great pressure to minimize this situation.

Thanks in advance,

Roberto Veiga

Veja quais são os assuntos do momento no Yahoo! + Buscados: Top 10 - Celebridades - Música - Esportes Veja quais são os assuntos do momento no Yahoo! +Buscados http://br.maisbuscados.yahoo.com

--
http://www.freelists.org/webpage/oracle-l
Received on Mon Jun 01 2009 - 10:21:37 CDT

Original text of this message