RE: Is it possible to disable SQL Directive collection for few tables?

From: Iggy Fernandez <iggy_fernandez_at_hotmail.com>
Date: Wed, 2 Dec 2015 09:08:35 -0800
Message-ID: <BLU179-W113341FD29045AD1E5D344EB0E0_at_phx.gbl>

After disabling directive generation and usage, you can take a weedwhacker to any previously created directives, extensions, and statistics Something like this. Use at your own risk. Make sure you understand the impact.
-- delete directives

column directive_id format a30
EXEC DBMS_SPD.flush_sql_plan_directive;
SELECT to_char(directive_id) directive_id, type, enabled, stateFROM dba_sql_plan_directives; declareBEGIN FOR rec in (SELECT directive_id did FROM DBA_SQL_PLAN_DIRECTIVES) LOOP DBMS_SPD.DROP_SQL_PLAN_DIRECTIVE (directive_id => rec.did); END LOOP;END;/ SELECT to_char(directive_id) directive_id, type, enabled, stateFROM dba_sql_plan_directives;
-- delete all droppable extensions

column owner format a30column table_name format a30column extension format a60 SELECT owner, table_name, DBMS_LOB.substr(extension, 3000) extension FROM dba_stat_extensions WHERE droppable='YES'; declarebegin for c in ( select owner, table_name, extension_name from dba_stat_extensions where droppable='YES' ) loop dbms_stats.delete_column_stats (c.owner, c.table_name, c.extension_name); end loop;end;/ SELECT owner, table_name, DBMS_LOB.substr(extension, 3000) extension FROM dba_stat_extensions WHERE droppable='YES'; BEGIN FOR rec IN ( SELECT owner, table_name, DBMS_LOB.substr(extension, 3000) extension FROM dba_stat_extensions WHERE droppable='YES' ) LOOP DBMS_OUTPUT.put_line(rec.extension); DBMS_STATS.drop_extended_stats( rec.owner, rec.table_name, rec.extension ); END LOOP; END;/ SELECT owner, table_name, DBMS_LOB.substr(extension, 3000) extension FROM dba_stat_extensions WHERE droppable='YES';

From: yasser8_at_gmail.com
Date: Wed, 2 Dec 2015 22:30:31 +0530
Subject: Re: Is it possible to disable SQL Directive collection for few tables? To: ludovico.caldara_at_gmail.com
CC: oracle-l_at_freelists.org

Hi Ludovico,
Seems like even after disabling sql plan directives they are still used by dbms_stats to create extended statistics, so I think its not going to help Yogesh as his problem was due creation of extended statistics as directed by SPD. Please correct me if I am wrong.
Thanks,Yasser

On Wed, Dec 2, 2015 at 9:09 PM, Ludovico Caldara <ludovico.caldara_at_gmail.com> wrote: Hi Yogesh,

in 12cR1 there's no easy way to disable directives in advance for specific tables.

What you can do:
1. wait for the directives to be created (after a few misestimates) and then disable them manually with pl/sql (notice that deleting them doesn not guarantee that you will not have them recreated later)

BEGIN
  FOR rec in (select d.directive_id as did from dba_sql_plan_directives d join dba_sql_plan_dir_objects o on     (d.directive_id=o.directive_id) where o.owner='APPUSER' and o.object_name in ('TAB','TAB_PROP'))   LOOP
    DBMS_SPD.ALTER_SQL_PLAN_DIRECTIVE ( rec.did, 'ENABLED','NO');   END LOOP;
END;
/

2. you can stage/export/import directives from one DB to another one, this will keep the directive status.

I've explained this step in my blog:
http://www.ludovicocaldara.net/dba/sql-plan-directives-problem/

3. as last resort, disable the whole adaptive features. I generally do not recommend it, but sometimes I do it :-)

HTH--
Ludovico

2015-12-01 5:51 GMT+01:00 Tiwari, Yogesh <Yogesh.Tiwari_at_fidelity.co.in>:

Oracle-l , Is it possible to disable SQL directive collection for few tables? We are on 12.1.0.2 PSU4, linux x86-64. We saw perf degradation after upgrade to 12c. One of the query, huge 500lines, involving complex views, saw change in plan, and even baselines are getting ignored, that we got from 11g db. Later, we compared stats from 11g db, and deleted extended stats, and it worked like charm. Hence, the question. Thanks, Yogi Disclaimer: The information transmitted is intended for the person or entity to which it is addressed and may contain confidential, privileged or copyrighted material or attorney work product. If you receive this in error, please contact the sender and delete the material from any computer. Any comments or statements made are not necessarily those of FIL India Business Services Private Limited or any other Fidelity entity. All e-mails may be monitored or recorded.                                                

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Received on Wed Dec 02 2015 - 18:08:35 CET