Message-ID: <46EAE28A.3040708@ora-600.net>
Date: Fri, 14 Sep 2007 12:35:38 -0700
From: Jeremiah Wilton <jeremiah@ora-600.net>
User-Agent: Thunderbird 1.5.0.9 (Windows/20061207)
MIME-Version: 1.0
To:  don@seiler.us
CC: oracle-l <oracle-l@freelists.org>
Subject: Re: Weird database hanging
References: <716f7a630709141119p6b28d084h1ee33adec81944ca@mail.gmail.com>
In-Reply-To: <716f7a630709141119p6b28d084h1ee33adec81944ca@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Sender: oracle-l-bounce@freelists.org
Errors-to: oracle-l-bounce@freelists.org
Precedence: normal
Reply-to: jeremiah@ora-600.net

Don

You are right that everything you saw in the logs are symptomsm, not 
root causes. Go back in dba_hist_active_sess_history aggregating 
sum(time_waited) by wait_class in  minute slices for the affected period 
and find the first sign of things going awry.

Drill down and find the waits that A) touched the whole thing off and B) 
sustained the hang.

Don't know whose article/posting suggested changing PROCESSES, but that 
sure sounds like a shot in the dark to me.  Oracle is heavily 
instrumented, and we should all use data before trying suggestions from 
Google.  Because you didn't restart Oracle, all the ASH data should have 
been preserved in AWR.

Jeremiah Wilton
ORA-600 Consulting
http://www.ora-600.net

Don Seiler wrote:
> Running 10gR2 (10.2.0.2) on RHEL4 on 4 64-bit dual-core box.  Earlier
> today users complained en masse about not being able to connect to the
> database.  I got to a term and found that even trying to log in
> locally as sysdba was hanging.
> 
> So in summary, there was hanging for everyone, it seemed to clear
> itself up.  One post on Google suggested that the PROCESSES init
> parameter might be too low.  Any other possibilities?
--
http://www.freelists.org/webpage/oracle-l