RE: direct path read & db_file_multiblock_read_count
From: Fergal Taheny <ftaheny_at_gmail.com>
Date: Fri, 25 Oct 2013 23:56:32 +0100
Message-ID: <CAOuMUT4_B7OfLDw=PHb-03aC-_3oUpPQVZ8ZB=oyeWJsykrokA_at_mail.gmail.com>
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?
Date: Fri, 25 Oct 2013 23:56:32 +0100
Message-ID: <CAOuMUT4_B7OfLDw=PHb-03aC-_3oUpPQVZ8ZB=oyeWJsykrokA_at_mail.gmail.com>
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
-- http://www.freelists.org/webpage/oracle-lReceived on Sat Oct 26 2013 - 00:56:32 CEST