Re: Solaris - db_file_multiblock_read

From: <Jared.Still_at_radisys.com>
Date: Mon, 19 Nov 2001 14:23:53 -0800
Message-ID: <F001.003C8DC0.20011119140017@fatcity.com>

Why not set it to 25?

Jared

                                                                                       
                                       
                    "Jeff Wiegard"                                                     
                                       
                    <JWIEGARD_at_ngwmail.des.st       To:     Multiple recipients of list 
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                    Sent by:                       Subject:     Solaris - 
db_file_multiblock_read_count                       
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                    11/19/01 01:20 PM                                                  
                                       
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                    ORACLE-L

Hi.

I was hoping for some confirmation here.

I'm running 8.0.5 on Solaris 2.7, with block size set to 8192. There is no 'maxphys' parameter in /etc/system.

After some testing, I've decided to set the db_file_multiblock_read_count = 24, based on the following:

SQL> alter session set db_file_multiblock_read_count = 1000;
select value from v$parameter where name = 'db_file_multiblock_read_count';

This gave me a value = 128

3. alter session set events '10046 trace name context forever, level 8';

4. select /*+ FULL(t) */ count(*) from sys.source$ t;

The trace file gave me the following:

WAIT #1: nam='db file scattered read' ela= 0 p1=1 p2=660 p3=25
WAIT #1: nam='db file scattered read' ela= 0 p1=1 p2=1167 p3=25
WAIT #1: nam='db file scattered read' ela= 0 p1=1 p2=1207 p3=25
WAIT #1: nam='db file scattered read' ela= 0 p1=1 p2=1272 p3=25
WAIT #1: nam='db file scattered read' ela= 0 p1=1 p2=1312 p3=25

So then setting db_file_multiblock_read_count to 24 would be about right ... right?

Thanks,

Jeff

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Received on Mon Nov 19 2001 - 16:23:53 CST

Re: Solaris - db_file_multiblock_read_count