RE: ORACLE automatic update statistics better??
- From: "Powell, Mark" <mark.powell2@xxxxxx>
- To: "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 13 Aug 2010 17:03:14 +0000
Maybe, maybe not. The default is for Oracle to choose the histogram size (FOR
ALL COLUMNS SIZE AUTO) while repeat would lock you in. On some tables that may
be good but in some cases that may be the wrong choice.
The default notes another difference from the OP's command and Oracle's namely
Oracle calculates the histogram on all columns, not just indexed ones.
-----Original Message-----
From: Michael Dinh [mailto:mdinh@xxxxxxxxx]
Sent: Friday, August 13, 2010 12:09 PM
To: Powell, Mark; oracle-l@xxxxxxxxxxxxx
Subject: RE: ORACLE automatic update statistics better??
Isn't it better to use REPEAT for method_opt?
If auto statistic gathering is using histogram and you gather without
histogram, next time histogram will be gathered, no?
You can find the default method_opt by executing - select
dbms_stats.get_param('method_opt') from dual;
exec
dbms_stats.gather_table_stats(user,tabname=>'&tbl',estimate_percent=>1,cascade=>TRUE,method_opt=>'FOR
ALL COLUMNS SIZE REPEAT');
Michael Dinh : XIFIN : 858.436.2929
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-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Powell, Mark
Sent: Friday, August 13, 2010 8:14 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: RE: ORACLE automatic update statistics better??
The Oracle provided job will gather histograms by default and that is pretty
the main difference from the statistics collection command you posted.
You should not need to manually gather statistics except in those cases where
you create and load a new table and want statistics now rather than wait on the
Oracle job task to generate statistics and in those cases where the generated
statistics do now work well. You may be better off without histograms on a
specific table, etc....
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of dba1 mcc
Sent: Friday, August 13, 2010 11:09 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: ORACLE automatic update statistics better??
we have ORACLE 10GR2 on LINUX server. Our consultant don't allow us "manually"
to run "update statistics". Consultant say ORACLE 10GR2 automatic update
statistics algorithm better than manually command.
The SQL command we used to manually run is:
execute DBMS_STATS.GATHER_SCHEMA_STATS (ownname=> UPPER('&ID'),
estimate_percent=> dbms_stats.auto_sample_size, method_opt=> 'FO R ALL INDEXED
COLUMNS SIZE 1', DEGREE=> DBMS_STATS.DEFAULT_DEGREE, cascade=>TRUE)
I would like listen your opinion.
Thanks.
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