Comments
| Stored Outlines and Plan Stability - Use stored outlines to maintain consistent execution plans regardless of changes in the system environment or associated statistics. |
| Arindam Mukherjee said... It's really worth reading and it has helped me a lot get a clear picture of this topic. I highly appreciate this effort. |
| Rich said... Think you should consider removing the reference to query_rewrite_enabled. This is not specifically required to create or use a stored outline and, at 9i at least, can cause real problems with other queries. |
| Tim... said... Hi. According to the 10g manual it is necessary: http://download-west.oracle.com/docs/cd/B14117_01/server.101/b10752/outlines.htm#15583 Cheers Tim... |
| rich said... Tim, Thanks for replying. I believe this is what the doc you refer to says: "Settings for several parameters, especially those ending with the suffix _ENABLED, must be consistent across execution environments for outlines to function properly. These parameters are: QUERY_REWRITE_ENABLED STAR_TRANSFORMATION_ENABLED OPTIMIZER_FEATURES_ENABLE" Sorry to be pedantic but I recently fell into this trap and had to raise a tar to confirm I did not need query_rewrite. |
| Richard said... You have this: -- Switch on automatic creation of stored outlines. ALTER SYSTEM SET create_stored_outlines=TRUE; ALTER SESSION SET create_stored_outlines=TRUE; -- Switch on automatic creation of stored outlines. ALTER SYSTEM SET create_stored_outlines=FALSE; ALTER SESSION SET create_stored_outlines=FALSE; Second one needs to say "Switch off ..." . Nice article! |
| Ashish Kohli said... Excellent stuff... |
Don't ask technical questions here, that's what the forum is for!
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