Re: db_file_multiblock_read_count

From: Keith Moore <>
Date: Mon, 29 Sep 2008 20:25:15 -0500 (CDT)
Message-ID: <>

The writes will not cross extent boundaries so if you use AUTOALLOCATE for extent management and it starts with 64K extents then that is all that will be returned in a single read. Once the extent size reaches 1M or larger then it's not an issue.


> I have always been a little humored by this parameter.
> db_file_multiblock_read_count attempts to specify a maximum value, as does
> the MBRC collected by system stats. However, that does not determine how
> many blocks are actually scooped up in a multiblock pass. One good example
> is to set event 10046 on a full table scan with waits (level 8 or 12) and
> look for db file scattered read waits, which will have the number of blocks
> read during the wait.

Received on Mon Sep 29 2008 - 20:25:15 CDT

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