Oracle-L: Re: Why does increasing db_block_buffers make this query run faster?

From: Andrew Babb <andrewb_at_HK.SUPER.NET>
Date: Mon, 4 Mar 1996 08:45:16 +0800
Message-Id: <9603040103.AA28842@alice.jcc.com>

On Sun, 3 Mar 1996, Steve Peters wrote:

> Hi fellow Oracle fans,
>
> I wonder if anyone can shed some light on this: We have a query which runs
> pretty slowly anyway, but when I ran it on our test database it ran much
slower.
> Here is the tkprof output:

<SNIP>
>
> I don't understand why/how increasing db_block_buffers reduces the number of
> physical disk reads required for the query. Thanks in advance for any help
that
> you may give.
>
> Regards Steve.

The reduction in the disk reads will probably be caused by the multiblock read count parameter, which is derived from db_block_buffers and processes. By increasing the size of the db_block_buffers, the db_file_multiblock_read_count also increases, if you have not already set this.

Andrew Babb
Database Consultant Received on Sun Mar 03 1996 - 20:04:01 CST