Property Description
Parameter type Integer
Default value 1048576 (1 MB)
Modifiable No
Range of values Operating system-dependent
Basic No


Oracle does not recommend using the BITMAP_MERGE_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. BITMAP_MERGE_AREA_SIZE is retained for backward compatibility.

BITMAP_MERGE_AREA_SIZE is relevant only for systems containing bitmap indexes. It specifies the amount of memory Oracle uses to merge bitmaps retrieved from a range scan of the index. The default value is 1 MB. A larger value usually improves performance, because the bitmap segments must be sorted before being merged into a single bitmap.

See Also:

Oracle Database Performance Tuning Guide for more information on setting this parameter