Antwort: RE: SYSSTAT statistics for buffer writes?

From: Martin Klier <>
Date: Wed, 25 Feb 2009 12:07:12 +0100
Message-ID: <>

Hi Tanel,

> "Tanel Poder" <>
> 25.02.2009 11:30
> Documentation is wrong. Conventional path inserts will be shown in "db
> changes". Direct path load blocks are not shown in there though.
That would be great. But how do you know?

> Btw, you can use v$segment_statistics to get a segment level breakdown of
> logical reads vs db block changes.

Very nice to know, I will check this these days.

> However I have to ask, what are you trying to achieve with this? Read vs
> write ratio isn't too useful statistic for people and business,
> if measured from such low level.

I won't say "measure". It's an idea to get raw information about software behaviour under different circumstances.

Thanks so far!

> > -----Original Message-----
> > I need to create a statistics overview for reads vs. writes
> > on a 10gR2 database. Desire is, to compare "session logical
> > reads" ('The sum of "db block gets" plus "consistent gets".
> > This includes logical reads of database blocks from either
> > the buffer cache or process private memory.' by 10g
> > documentation) with its counterpart in writing. I don't want
> > to gather information about phyiscal IO.


Mit freundlichem Gruß

Martin Klier

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Received on Wed Feb 25 2009 - 05:07:12 CST

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