1.34 BITMAP_MERGE_AREA_SIZE

BITMAP_MERGE_AREA_SIZE specifies the amount of memory Oracle uses to merge bitmaps retrieved from a range scan of the index.

Property Description

Parameter type

Integer

Default value

1048576 (1 MB)

Modifiable

No

Modifiable in a PDB

Yes

Range of values

Operating system-dependent

Basic

No

Note:

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. A larger value usually improves performance, because the bitmap segments must be sorted before being merged into a single bitmap.

See Also:

Oracle Database SQL Tuning Guide for more information on using bitmap indexes for performance