Migrating Stored Outlines

11gR2 provides a function to migrate stored outline in to SQL plan baselines. In 1359841.1 oracle says stored outline "will be desupported in a future release in favor of SQL plan management" but (still) outline migration only works with enterprise edition (what will happen to standard edition systems?). This post list steps to migrate stored outlines created in earlier posts.

Current outlines

SQL> select name,sql_text,migrated from  user_outlines;
NAME            SQL_TEXT                                               MIGRATED
------------    ------------------------------------------------------ -------------
WITH_INDEX      select count(*) from big_table where p_id=:"SYS_B_0"   NOT-MIGRATED
JDBC_OUTLINE    select count(*) from big_table where p_id=:1           NOT-MIGRATED

Execute DBMS_SPM.MIGRATE_STORED_OUTLINE function to migrate a particular outline

var migrate_output clob
SQL> exec :migrate_output := dbms_spm.MIGRATE_STORED_OUTLINE(attribute_name => 'outline_name',
                                                             attribute_value => 'JDBC_OUTLINE',
                                                             fixed => 'NO');
PL/SQL procedure successfully completed.

Once migrated the outline view shows plant status as migrated

SQL> select name,sql_text,migrated from  user_outlines;
NAME            SQL_TEXT                                               MIGRATED
------------    ------------------------------------------------------ -------------
WITH_INDEX      select count(*) from big_table where p_id=:"SYS_B_0"   NOT-MIGRATED
JDBC_OUTLINE    select count(*) from big_table where p_id=:1           MIGRATED

Query plan base line view to verify outline is migrated into a SQL plan base line.

SQL> select sql_handle,sql_text,plan_name,origin,enabled,accepted from dba_sql_plan_baselines;

SQL_HANDLE           SQL_TEXT                                      PLAN_NAME     ORIGIN         ENA ACC
-------------------- --------------------------------------------- ------------- -------------- --- ----
SQL_fcd5bfb6b7986086 select count(*) from big_table where p_id=:1  JDBC_OUTLINE  STORED-OUTLINE YES YES

Origin column indicates that plan baseline was created from a stored outline. Run the SQL query if plan base line is used

SQL> select * from table(dbms_xplan.display_cursor('4x4krrt8vq3js',0,'ALLSTATS OUTLINE'));
SQL_ID  4x4krrt8vq3js, child number 0
-------------------------------------
select count(*) from big_table where p_id=:1

Plan hash value: 3425075646

---------------------------------------------------------
| Id  | Operation          | Name              | E-Rows |
---------------------------------------------------------
|   0 | SELECT STATEMENT   |                   |        |
|   1 |  SORT AGGREGATE    |                   |      1 |
|*  2 |   TABLE ACCESS FULL| big_table |  21352 |
---------------------------------------------------------

Outline Data
-------------

  /*+
      BEGIN_OUTLINE_DATA
      IGNORE_OPTIM_EMBEDDED_HINTS
      OPTIMIZER_FEATURES_ENABLE('11.2.0.3')
      DB_VERSION('11.2.0.3')
      OPT_PARAM('optimizer_index_cost_adj' 25)
      OPT_PARAM('optimizer_index_caching' 90)
      FIRST_ROWS(1000)
      OUTLINE_LEAF(@"SEL$1")
      FULL(@"SEL$1" "big_table"@"SEL$1")
      END_OUTLINE_DATA
  */

Predicate Information (identified by operation id):
---------------------------------------------------

   2 - filter("p_id"=:1)

Note
-----
   - SQL plan baseline JDBC_OUTLINE used for this statement
   - Warning: basic plan statistics not available. These are only collected when:
       * hint 'gather_plan_statistics' is used for the statement or
       * parameter 'statistics_level' is set to 'ALL', at session or system level

Outline takes precedence over plan baseline (see 1524658.1 for more). Once migrated outline is not use even though the enabled column says "ENABLED" in the outline view. But if the outline was to be recreated again then instead of SQL plan baseline , the stored outline will be used. To recreate the outline that was migrated create a private outline and refresh from it.

SQL> create private outline myjdbc from jdbc_outline;
Outline created.

SQL> execute dbms_outln_edit.refresh_private_outline('MYJDBC');
PL/SQL procedure successfully completed.

SQL> create or replace outline jdbc_outline from private MYJDBC;
Outline created.

After this the migrated status would be changed to not-migrated

SQL> select name,sql_text,migrated from  user_outlines;
NAME            SQL_TEXT                                               MIGRATED
------------    ------------------------------------------------------ -------------
WITH_INDEX      select count(*) from big_table where p_id=:"SYS_B_0"   NOT-MIGRATED
JDBC_OUTLINE    select count(*) from big_table where p_id=:1           NOT-MIGRATED

and outline will take precedence over the existing plan baseline.

Related Posts
Changing Execution Plan Using Stored Outline
Moving Stored Outlines From One Database To Another