Re: Redo Copy Latches

From: Steve Adams <steveadams_at_acslink.net.au>
Date: 1997/11/04
Message-ID: <345e95c4.104344128@newsserver.trl.oz.au>#1/1

Correction !!!

Having checked, I find that it is actually the other way around. Under 7.3 the redo copy latches are level 6 latches and the redo allocation latch is a level 7 latch. This means that it is OK to ask for the redo allocation latch while holding a copy latch, but not vice versa. On earlier versions, the redo copy latches were level 8 latches.

Regards,
Steve Adams
steveadams_at_acslink.net.au

---

On Mon, 03 Nov 1997 03:09:45 GMT, steveadams_at_acslink.net.au (Steve Adams) wrote:

>I think the answer is that as of 7.3 for any redo entry, a copy latch
>is requested in immediate mode initially and if obtained the
>allocation latch is released, otherwise the allocation latch is held
>and the copy proceeds on the allocation latch. When the copy has
>finished the latch is released, which may be either an allocation or a
>copy latch,
>
>In earlier versions, it worked the other way: a copy latch was
>obtained first, and then the allocation latch (unless the entry was
>less than the small entry threshold, of course).
Received on Tue Nov 04 1997 - 00:00:00 CST