RE: direct path read & db_file_multiblock_read_count
- From: "Hameed, Amir" <Amir.Hameed@xxxxxxxxx>
- To: "ftaheny@xxxxxxxxx" <ftaheny@xxxxxxxxx>
- Date: Fri, 25 Oct 2013 23:00:50 +0000
Hi Fergal,
direct path reads do not go through the buffer cache. They are read directly
into the PGA of the process. If these were 'scattered reads' then your argument
would be valid.
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Fergal Taheny
Sent: Friday, October 25, 2013 6:57 PM
To: Hameed, Amir
Cc: oracle-l-freelists
Subject: RE: direct path read & db_file_multiblock_read_count
Hi,
Is it because lots of the table's blocks are already in the buffer cache
and the direct path reads vary the read sizes to avoid reading blocks that
are already in cache. If you flush the buffer cache and rerun the query do
you get more 128 block reads?
Fergal
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