Why I get different 'db file scattered read' values?

From: Juan Carlos Reyes Pacheco <jreyes_at_dazasoftware.com>
Date: Mon, 19 Jul 2004 13:34:11 -0400
Message-Id: <40FC0613.000003.01588@CACHITOSS>

Hi list, I runt the following script to get the DB_FILE_MULTIBLOCK_READ_COUNT value  

SQL> ALTER SESSION SET DB_FILE_MULTIBLOCK_READ_COUNT =100;
SQL> SET AUTOTRACE TRACEONLY
SQL> ALTER SESSION SET TRACEFILE_IDENTIFIER='TEST_BLOCK_SIZE';
SQL> ALTER SESSION SET EVENTS '10046 TRACE NAME CONTEXT FOREVER, LEVEL
SQL> SELECT /*+ FULL(A) */ * FROM ADM.TRANSAC_ME A;

371196 filas seleccionadas.
Execution Plan

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0 SELECT STATEMENT Optimizer=CHOOSE (Cost=206 Card=308952 Byte s=46342800)  

1 0 TABLE ACCESS (FULL) OF 'TRANSAC_ME' (Cost=206 Card=308952 Bytes=46342800)
Statistics

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1118 recursive calls
0 db block gets
33023 consistent gets
8490 physical reads
60 redo size
31569813 bytes sent via SQL*Net to client 272709 bytes received via SQL*Net from client 24748 SQL*Net roundtrips to/from client
6 sorts (memory)
0 sorts (disk)  

But I get the different values in p3

WAIT #1: nam='db file scattered read' ela= 32568 p1=3 p2=51689 p3=8
WAIT #1: nam='db file scattered read' ela= 15915 p1=3 p2=51778 p3=7
WAIT #1: nam='db file scattered read' ela= 16483 p1=3 p2=51785 p3=8
WAIT #1: nam='db file scattered read' ela= 29985 p1=3 p2=51937 p3=8
WAIT #1: nam='db file scattered read' ela= 150 p1=3 p2=52050 p3=7
 

Any idea?, my ntfs disk is compressed.  

Juan Carlos Reyes Pacheco
OCP

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Received on Mon Jul 19 2004 - 12:36:05 CDT