Re: Lock requests queued?
From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Wed, 20 Jun 2012 08:29:18 +0100
Message-ID: <4a6dnaUR39ZW5nzSnZ2dnUVZ8vOdnZ2d_at_bt.com>
Date: Wed, 20 Jun 2012 08:29:18 +0100
Message-ID: <4a6dnaUR39ZW5nzSnZ2dnUVZ8vOdnZ2d_at_bt.com>
The lock requests are queued.
If you're really interested in such mechanisms, see ch. 4 of Oracle Core.
http://books.google.co.uk/books?id=G9AJA91PL54C&lpg=PA77&dq=oracle%20core%20locks&pg=PA77#v=onepage&q=oracle%20core%20locks&f=false
-- Regards Jonathan Lewis http://jonathanlewis.wordpress.com/all_postings Author: Oracle Core (Apress 2011) http://www.apress.com/9781430239543 "Frank Langelage" <frank_at_lafr.de> wrote in message news:a4bq3mFco5U1_at_mid.individual.net...Received on Wed Jun 20 2012 - 02:29:18 CDT
| To serialize some kind of data modifications our application uses an
| exclusive table lock (lock table %s in exclusive mode).
| The process retrieves some data, then acquires the lock and does the
| modifications. Then work is committed and with that the lock is released.
| After process 1 has acquired the lock at time t1, other processes might
| come and require the lock. Lets say process 2 at t2 and process 3 at t3.
| Is it guaranteed, that the process 2 will be the next to get the lock
| because it was first who tried to get it, so waiting for the longest
| time? Or maybe better: are the lock requests queued?
| Or is it more or less random, depending which of the Oracle
| processes/threads gets CPU time?
|
| (Oracle server version 10.2 or 11.2 on Windows, IBM AIX and Solaris
SPARC).