Oracle-L: RE: SQL Query

From: Bellow, Bambi <bbellow_at_chi.navtech.com>
Date: Fri, 14 Nov 2003 11:04:25 -0800
Message-ID: <F001.005D6B09.20031114110425@fatcity.com>

Nice try. Same result.

1 select a. tablespace_name, sum(b.user_bytes)/(1024*1024) allocated,   2 sum(a.bytes)/(1024*1024) used, round(sum(a.bytes)/sum(b.user_bytes),4) pct
  3 from dba_extents a, dba_data_files b   4 where a.tablespace_name=b.tablespace_name   5 and a.tablespace_name='NAUAT'
  6* group by a.tablespace_name,b.tablespace_name SQL> /

TABLESPACE_NAME                 ALLOCATED       USED        PCT
------------------------------ ---------- ---------- ----------
NAUAT                          31772837.3      23018      .0007

Also, note that both the allocated *and* used values are wrong...they should be

TABLESPACE_NAME                MEGS_ALLOCATED  MEGS_USED        PCT
------------------------------ -------------- ---------- ----------
NAUAT                                22924.25      11509         50

-----Original Message-----
Sent: Friday, November 14, 2003 12:44 PM To: Multiple recipients of list ORACLE-L

Bambi,
I think that the query (2) will return the the same count as query (1) if you use the
column user_bytes from the dba_data_files rather than the column bytes.
If I sum the bytes from dba_extents for a tablespace_name xxx and sum the user_bytes from dba_data_files for tablespace_name xxx I get the same value.

I my case the tablespace is a partitioned table with LMT . size 38M with 2 M uniform extents. I did not use 100 % of each extent there fore the different between bytes and user_bytes. Ron
> bbellow_at_chi.navtech.com 11/14/2003 12:44:26 PM >>> Friends --

Why would these two queries return different results?

This query works.

SQL> l
1 select
a.tablespace_name,megs_allocated,megs_used,round(megs_used/b.megs_allocated, 2)*100 pct
2 from (select tablespace_name,sum(bytes)/(1024*1024) megs_used 3 from dba_extents group by tablespace_name) a, 4 (select tablespace_name,sum(bytes)/(1024*1024) megs_allocated 5 from dba_data_files group by tablespace_name) b 6 where a.tablespace_name=b.tablespace_name 7* and a.tablespace_name='NAUAT'
SQL> /

TABLESPACE_NAME                MEGS_ALLOCATED  MEGS_USED        PCT
------------------------------ -------------- ---------- ----------
NAUAT                                22924.25      11509         50

This query does not work

1 select a.tablespace_name,sum(b.bytes)/(1024*1024) megs_allocated, 2 sum(a.bytes)/(1024*1024) megs_used, 3 round(sum(a.bytes)/sum(b.bytes),4)*100 pct 4 from dba_extents a, dba_data_files b 5 where a.tablespace_name=b.tablespace_name 6 and a.tablespace_name='NAUAT'
7* group by a.tablespace_name,b.tablespace_name SQL> /

TABLESPACE_NAME                MEGS_ALLOCATED  MEGS_USED        PCT
------------------------------ -------------- ---------- ----------
NAUAT                              31773010.5      23018        .07

Bambi.
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Author: Bellow, Bambi
INET: bbellow_at_chi.navtech.com

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