For example, you may need to alter the
outline to reflect significant changes in data volumes and distribution. You can use the rebuild
clause of the alter outline command to regenerate the hints used during query execution, as
shown next:
alter outline YTD_SALES rebuild;
You can also rename an outline via the rename clause of the alter outline command, as
shown here:
alter outline YTD_SALES rename to YTD_SALES_REGION;
You can change the category of an outline via the change category clause, as shown in the
following example:
alter outline YTD_SALES_REGION change category to DEFAULT;
To manage stored outlines, use the DBMS_OUTLN package, which gives you the following
capabilities:
Drop outlines that have never been used
Drop outlines within a specific category
Move outlines from one category to another
Create outlines for specific statements
Update outlines to the current version??™s signature
Reset the usage flag for an outline
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142 Oracle Database 11g DBA Handbook
Each of these capabilities has a corresponding procedure within DBMS_OUTLN. To drop
outlines that have never been used, execute the DROP_UNUSED procedure, as shown in the
following example:
execute DBMS_OUTLN.DROP_UNUSED;
You can clear the ???used??? setting of an outline via the CLEAR_USED procedure. Pass the name
of the outline as the input variable to CLEAR_USED:
execute DBMS_OUTLN.CLEAR_USED('YTD_SALES_REGION');
To drop all the outlines within a category, execute the DROP_BY_CAT procedure.
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