RE: Advanced Queueing

  • From: "Post, Ethan" <Ethan.Post@xxxxxx>
  • To: <awellsdba@xxxxxxxxx>, <chris@xxxxxxxxxxxxxxxxxxxxx>
  • Date: Wed, 10 Nov 2004 07:45:31 -0600

We use AQ quite a bit, watch out for some character set bugs, there are
some character sets you can not use with AQ.  Also import/export with
queues is hell.  Export/import user level you will have issues since you
usually don't want to drop your queues before exporting (not sure if
that even solves the problem).  There is an article on metalink about
the issue.  We basically have a cleanup process which deletes from SYS
tables to get the queues uninstalled after import so we can recreate

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of aj wells
Sent: Wednesday, November 10, 2004 6:20 AM
To: chris@xxxxxxxxxxxxxxxxxxxxx
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: Advanced Queueing

Don't know a whole lot honestly.  We were going to try to impliment at
my last job because "we" throught they were totally cool and good for
something ("we" were into really cool even if not practial or
applicable).  THIS situation, I think it will help, but I really want
to prove out whether it will or not with a production load.

Will go look at the Feuerstein book... just because it is Oracle8
doesn's mean it isn't still applicable.

Read the note (that is why I want to do load tests and dink around
with stripe sizes)

There are indexes that can be built (if I am reading what I DID find
correctly) to help with the enqueues and the dequeues, so the
'feature' might be fixed in 9i.

I was thinking that it might be a good idea to test out with one
broker at first, and add an additional broker or two to help with the

Thank you... it helps

On Wed, 10 Nov 2004 09:44:14 +0000, chris@xxxxxxxxxxxxxxxxxxxxx
<chris@xxxxxxxxxxxxxxxxxxxxx> wrote:
> April,
> Not sure how much you already know about AQ so you may already be
aware of all
> of this:
> 1. Good introduction to AQ is in Steven Feuerstein's "Oracle Built-in
> book, I know it's Oracle 8 but it's still good for the basics.
> 2. Metalink note 102926.1 has some info that may be helpful to you.
> 3. One gotcha from my experience using AQ on 8.1.7 (maybe resolved in
9i) is
> that one of the standard AQ procedures, I think it's dbms_aq.dequeue,
does a
> full table scan of the queue table every time it's called.
> This means you must keep the number of messages on the queue table to
a minimum
> and if for some reason you get a temporary build up of messages then
> need to do some housekeeping on the queue table to bring down the high
> mark and avoid all the unnecessary IO. (I had a regular procedure for
> this on an AQ system I worked on a year or so ago.)
> As a result of this FTS issue you need to consider how many queues you
map to
> each queue table.
> Chris
> Quoting aj wells <awellsdba@xxxxxxxxx>:
> > A little bird pointed out that there is a wealth of information on
> > Advance Queueing on this list... and I was hoping (since google
> > giving me what I want) someone would have pointers to where good
> > papers on setting up and tuning AQ might be.
> >
> > THIS job is REALLY starting to be fun...
> >
> > April
> > --
> >
> >
> Chris Dunscombe
> Christallize Ltd
> -------------------------------------------------
> Everyone should have

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