Property | Description |
---|---|
Parameter type |
Integer |
Default value |
|
Modifiable |
No |
Range of values |
Operating system-dependent |
Basic |
No |
Note:
Oracle does not recommend using the CREATE_BITMAP_AREA_SIZE
parameter unless the instance is configured with the shared server option. Oracle recommends that you enable automatic sizing of SQL working areas by setting PGA_AGGREGATE_TARGET
instead. CREATE_BITMAP_AREA_SIZE
is retained for backward compatibility.
CREATE_BITMAP_AREA_SIZE
is relevant only for systems containing bitmap indexes. It specifies the amount of memory (in bytes) allocated for bitmap creation. A larger value may speed up index creation.
Cardinality is the number of unique values in a column in relation to the number of rows in the table. If cardinality is very small, you can set a small value for this parameter. For example, if cardinality is only 2, then the value can be in kilobytes rather than megabytes. As a general rule, the higher the cardinality, the more memory is needed for optimal performance.
See Also:
Oracle Database SQL Tuning Guide for more information on using bitmap indexes