Re: Logical Reads from v$segment_statistics at the tablespace level!

From: Arup Nanda <orarup_at_hotmail.com>
Date: Thu, 17 Apr 2003 21:46:38 -0800
Message-ID: <F001.005849C5.20030417214638@fatcity.com>

All these stats from v$segment_statistics mean nothing at the tablespace level; only at the segment level. In your query, selectthe segment, too.

Arup

>From: Murali Menon <mjgnmenon_at_yahoo.com>
>Reply-To: ORACLE-L_at_fatcity.com
>To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
>Subject: Logical Reads from v$segment_statistics at the tablespace level!
>Date: Thu, 17 Apr 2003 18:46:59 -0800
>
>
>During a recent test on Oracle 9.2.0 3 just noticed some high logical reads
>generated through the v$segment_statsitics view, I can relate buffer busy
>waits and physical reads however, what does 'logical reads' at the segment
>level on a tablespace indicate?
>
>SQL> COL VALUE FORMAT 99999999
>SQL> SELECT TABLESPACE_NAME,STATISTIC_NAME,VALUE from V$SEGMENT_STATISTICS
>WHERE
> 2 OWNER NOT IN ('SYS','SYSTEM') AND VALUE > 100 ORDER BY VALUE DESC;
>
>TABLESPACE_NAME STATISTIC_NAME VALUE
>-------------------- ----------------------------------- ---------
>MED_DATA_001 logical reads 21260912
>MED_INDX_001 logical reads 13275744
>MED_DATA_001 logical reads 13254432
>MED_INDX_001 logical reads 10721792
>LAR_DATA_001 logical reads 10616944
>MED_DATA_001 physical reads 7169875
>LAR_DATA_001 physical reads 5206083
>SMA_INDX_001 logical reads 1915440
>MED_DATA_001 logical reads 1214416
>MED_INDX_001 logical reads 1123120
>SMA_DATA_001 logical reads 1031616
>
>TABLESPACE_NAME STATISTIC_NAME VALUE
>-------------------- ----------------------------------- ---------
>MED_DATA_001 physical reads 987820
>SMA_DATA_001 logical reads 926608
>MED_DATA_001 buffer busy waits 925822
>MED_DATA_001 physical reads 831576
>LAR_DATA_001 buffer busy waits 817668
>MED_INDX_001 physical reads 610602
>MED_INDX_001 logical reads 602368
>SMA_INDX_001 logical reads 580128
>SMA_INDX_001 logical reads 489632
>MED_DATA_001 logical reads 485920
>MED_INDX_001 physical reads 471294
>
>
>Menon
>
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Author: Arup Nanda
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Received on Fri Apr 18 2003 - 00:46:38 CDT