RE: query for waiters queue

From: Timur Akhmadeev <Akhmadeev_at_NetCracker.com>
Date: Tue, 22 Jan 2013 06:50:30 +0000
Message-ID: <FFB456FD9AC03C48B943326F553A70AC505873C9_at_umaildb2.netcracker.com>

Here's a screenshot of 3 sessions as described, and v$wait_chains shows what I would expect. https://www.dropbox.com/s/ebmsuh3hmygjt5p/wait_chains01.png

Regards
Timur Akhmadeev

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From: oracle-l-bounce_at_freelists.org [oracle-l-bounce_at_freelists.org] on behalf of Jonathan Lewis [jonathan_at_jlcomp.demon.co.uk] Sent: Friday, January 18, 2013 17:30
To: oracle-l
Subject: Re: query for waiters queue

I've just tried a simple test on an 11.2.0.3 instance. Get 3 sessions to lock a table in exclusive mode - one gets it, the other two queue.
The query returned no rows. In fact v$wait_chain held no rows.

I haven't checked the documentation yet, but the waits captured by v$wait_chain may include all the common waits we might like.

Regards

Jonathan Lewis
http://jonathanlewis.wordpress.com/all-postings

Author: Oracle Core (Apress 2011)
http://www.apress.com/9781430239543

• Original Message ----- From: "John D Parker" <orclwzrd_at_yahoo.com> To: "Sriram Kumar" <k.sriramkumar_at_gmail.com> Cc: "oracle-l" <oracle-l_at_freelists.org> Sent: Wednesday, January 16, 2013 6:32 PM Subject: Re: query for waiters queue

| It appears that you win the prize!
|
| ________________________________
| From: Sriram Kumar <k.sriramkumar_at_gmail.com>
| To: orclwzrd_at_yahoo.com
| Cc: oracle-l <oracle-l_at_freelists.org>
| Sent: Wednesday, January 9, 2013 7:51 PM
| Subject: Re: query for waiters queue
|
|
| Hi,
|
| you can look at the following script by Guy Harrison. Displays the chain
of locks
|
| http://guyh.textdriven.com/OPSGSamples/Ch15/wait_chains.sql
|
| best regards
|
| sriram kumar
|
|
|
| On Thu, Jan 10, 2013 at 12:27 AM, John D Parker <orclwzrd_at_yahoo.com>
wrote:
|
| So I have all the classic queries for finding blockers and waiters. I
keep running into the situation where I have one holder and 600 waiters. I clear off the blocker and then another one picks up and blocks. Is there a query that will give the current waiter queue? I see that Jonathan talks about a trace event to create a trace file but that's not particularly useful in my situation. Anyone have a query for this?
| >Thanks in advance!
| >
| >John
| >
| >--
| >http://www.freelists.org/webpage/oracle-l
| >

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Received on Tue Jan 22 2013 - 07:50:30 CET