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Oracle® Database Reference 10g Release 2 (10.2) Part Number B14237-02 |
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# BITMAP_MERGE_AREA_SIZE

Property | Description
--- | ---
Parameter type | Integer
Default value | `1048576` (1 MB)
Modifiable | No
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. 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