CREATE_BITMAP_AREA

2.60 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	`0`
Modifiable	No
Modifiable in a PDB	Yes
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.