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Problem IT09066
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Status: Closed |
THE EFFECT ON SETTING AUS_AUTO_RULES=0 IS NOT CLEARLY DESCRIBED IN THE DOCUMENTATION |
| product: |
INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10 |
| Problem description: |
AUS_AUTO_RULES is one of the configuration parameters for
Automatic Update Statistics (AUS).
The documentation explains about it:
If enabled, statistics are updated using the higher of the
following default minimum guidelines or user-created
distribution options:
All tables are updated in LOW mode.
All the leading index keys are updated in HIGH mode.
All non-leading index keys are updated in MEDIUM mode.
The minimum resolution for MEDIUM mode is 2.0.
The minimum confidence for MEDIUM mode is 0.95.
The minimum resolution for HIGH mode is 0.5.
If the UPDATE STATISTICS statement was run manually for a table,
the UPDATE STATISTICS statements generated by the AUS
maintenance system do not reduce the level, resolution,
confidence, or sampling size options.
If disabled, user-created distribution options are used.
form
http://www-01.ibm.com/support/knowledgecenter/SSGU8G_12.1.0/com.
ibm.perf.doc/ids_prf_756.htm
the problem is the last sentence.
What exactly does happen when AUS_AUTO_RULES is set to 0?
What options will be used, and how will they be set. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* Informix 11.70, 12.10 *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* See Problem Conclusion *
**************************************************************** |
| Local Fix: |
|
| Solution |
If the AUS_AUTO_RULES parameter is disabled by being set to 0,
the Auto Update Statistics maintenance system checks which
columns have existing distributions and generates update
statistics statements to refresh them. |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 22.05.2015
30.12.2015
30.12.2015 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 12.10.xC6
|
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