Re: consistent read and LIO question

From: lsllcm <>
Date: Fri, 15 May 2009 09:26:24 -0700 (PDT)
Message-ID: <>

On May 15, 5:13 pm, mathewbutler <> wrote:
> If I read your trace correctly it shows 5 consistent reads taking
> place, but two of these didn't find the required blocks in the cache
> and therefore had to read from disk via 'db file sequential read'.
> If so, it looks like v$sysstat only records LIO that do not initiate a
> physical read.
> Mathew Butler

Hi Mathew,

Yes, 5 consistent reads is right. I use v$sysstat and v$statname wrongly. The correct way is to run the following in other session,

*** In other session, run the following (where SID = the sid of the other session) before and after an execution of the select statement in the other session.
select, s.value from v$sesstat s, v$statname n where s.statistic# = n.statistic# and s.sid = 123 and like 'consistent

I got it from below article

Jacky Received on Fri May 15 2009 - 11:26:24 CDT

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