Collecting correlation statistics
Use the Index Correlation Statistics window to specify setting for frequent
value statistics
Authorities and privileges
To specify settings for frequent value statistics:
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To open the Index Correlation Statistics window, click the Add or
Change push button on the Indexes page of the Index Statistics window.
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If you specified individual partitions on the Indexes page, select partitions
IDs from the Available partitions list.
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Specify the Collect key cardinalities check box to collect all of
the distinct values in all of the 1 to n key column combinations for the
specified indexes, where n is the number of columns in the index.
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To collection frequent value statistics, click the Add push
button and type values in the Frequent values statistics options
table:
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Number of Columns
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Indicates the number of key columns to concatenate together when collecting
frequent values from the specified index. Specifying '3' means to collect
frequent values on the concatenation of the first three key columns.
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Number of frequent values
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Indicates the number of frequent values to be collected. Specifying '15'
means collect 15 frequent values from the specified key columns.
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Click OK.