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Re: latch contention

From: Steve Adams <steve_adams_at_acslink.net.au>
Date: 1997/10/08
Message-ID: <343c0d0a.867808704@newsserver.trl.oz.au>#1/1

Hi Keith,

  1. Last time I looked (7.1.4) latches appeared to take 112 bytes each regardless of the type of latch, but it may have changed by now. Note that the "latches" shown in v$latch are actually types of latches and may in fact be comprised of numerous child latches, each of 112 bytes. This is particularly significant for the cache buffer chains latches.
  2. There are only a handful a latch contention situations that can be addressed by init.ora parameter tuning. For example, there are undocumented parameters that affect contention for the cache buffer chains and library cache latches. There are a number of other latch contention situations that can only be fixed by application changes - for example, the process allocation latch. Other latch contention situations may in fact be due to an Oracle software bug, and then the right approach is to request a patch. So, I suppose, the answer is that it all depends on the latch and the nature of the problem.

Regards, Steve Adams



Remove the _ from my email address to reply.

On Wed, 8 Oct 1997 10:18:04 GMT, Keith HO Ling Soon <ling.soon.ho_at_sap-ag.de> wrote:

>Hi,
>
>I have some query regarding latch contention.
>
>1. How is it possible to know the size of each of the 53 latches in
>the Oracle Server?
>
>2. How to reduce the latch contention for the rest of the latches other
>than the redo allocation and redo copy latches? I only know one method :
>by adjusting the parameter LOG_SIMULTANEOUS_COPIES and
>LOG_SMALL_ENTRY_MAX_SIZE, contention on the redo log buffer latches can
>be reduced.
>
>Thank you in advance.
>
>
>Best regards
>Keith
>
Received on Wed Oct 08 1997 - 00:00:00 CDT

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