Oracle FAQ | Your Portal to the Oracle Knowledge Grid |
![]() |
![]() |
Home -> Community -> Usenet -> c.d.o.tools -> Re: enqueue timeouts ?
In article <eaGN4.280$ac5.6562_at_news11-gui.server.ntli.net>,
"Guy Fullalove" <nospam_at_127.0.0.1> wrote:
> Oracle 7.3.4 on Solaris 2.6
>
> Can anyone tell me what enqueue timeouts are, if they are a problem,
and how
> to prevent them?
>
> Thanks
>
> --
> Guy Fullalove
> (guy.fullalove_at_which.net)
>
Enqueues are basically a lock on a resouce. The exact manner in which
they are accomplished varies by OS.
A timeouts is an indication that a process could not get a resource it wanted and had to go into a wait state. Note that enqueues are not first in first out but are given out as available so if process A gets a resource and B asks for it while it is inuse the B goes into a wait. A releases it and C asks for it. C gets it and B comes out of its wait and requests it again. C has the resource so B waits again.
Enqueue waits can be caused by:
-- 1) contention for specific row -- 2) tbl locks caused by unindexed FK -- 3) ST lock contention on non-temporary temp tablespace -- 4) no available transaction slot in block [initrans parameter]
-- Mark D. Powell -- The only advice that counts is the advice that you follow so follow your own advice -- Sent via Deja.com http://www.deja.com/ Before you buy.Received on Wed Apr 26 2000 - 00:00:00 CDT
![]() |
![]() |