SA0045 : Consider updating statistics as they appear outdated and may mislead the query optimizer |
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The topic describes the SA0045 analysis rule.
MessageConsider updating statistics as they appear outdated and may mislead the query optimizer
DescriptionThe rule checks the statistics on all tables and indexed views in the current database for outdated statistics.
Evaluation of the statistics can be based on the number of modified rows or on the last time the statistics were updated.
The rules used to evaluate the statistics using the number of modified rows are the same as the rules SQL Server uses to update statistics automatically.
These rules are as follows:
– If a table has 6 or fewer rows, statistics will be updated after 6 changes
– If a table has 500 or fewer rows, statistics will be updated after 500 changes
– If a table has more than 500 rows, statistics will be updated after 20% of the total rows plus 500 rows are modified,added or deleted
ScopeThe rule has a ContextOnly scope and is applied only on current server and database schema.
Parameters| Name | Description | Default Value |
|---|---|---|
| EvaluationMode |
The parameters specifies the rules used to evaluate the statistics and consider them outdated or not. |
ModifiedRows |
| ExpirationDays |
Number of days the after which statistics are considered outdated. The parameter is used only when the EvaluationMode is set to Period or Any. |
3 |
RemarksThe rule requires Analysis Context. If context is missing, the rule will be skipped during analysis.
CategoriesPerformance Rules, Maintenance Rules, Bugs
Additional InformationThere is no additional info for this rule.
See Also