Re: Flashback log file sync
From: Mladen Gogala <gogala.mladen_at_gmail.com>
Date: Sat, 12 May 2012 18:47:31 +0000 (UTC)
Message-ID: <pan.2012.05.12.18.47.31_at_gmail.com>
On Sat, 12 May 2012 07:26:46 +0100, Jonathan Lewis wrote:
Date: Sat, 12 May 2012 18:47:31 +0000 (UTC)
Message-ID: <pan.2012.05.12.18.47.31_at_gmail.com>
On Sat, 12 May 2012 07:26:46 +0100, Jonathan Lewis wrote:
> Why do you expect to read when all you're doing is writing - (I think I
> know the answer to that question):
When writing LOB data, oracle first has to prepare the space. It first has to read the "chunk" into the PGA. I proved this by increasing chunk to 32k. I could probably eliminate the direct reads completely, by changing the lob to be cached (blocks read during into the SGA). Of course, I would then get db file scattered reads instead.
-- http://mgogala.byethost5.comReceived on Sat May 12 2012 - 13:47:31 CDT