1.56 CREATE_BITMAP_AREA_SIZE
CREATE_BITMAP_AREA_SIZE specifies the amount of memory (in bytes) allocated for bitmap creation.
| Property | Description |
|---|---|
|
Parameter type |
Integer |
|
Default value |
|
|
Modifiable |
No |
|
Modifiable in a PDB |
No |
|
Range of values |
Operating system-dependent |
|
Basic |
No |
This parameter is relevant only for systems containing bitmap indexes.
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.
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