GROPU_BITMAP_MERGE

Introduction

The GROPU_BITMAP_MERGE function is used to merge multiple intermediate Bitmap objects and returns the cardinality of the merged result.

Syntax

groupBitmapMerge(bitmap_state)

Parameters

• bitmap_state: An intermediate BITMAP object, representing the Bitmap state to be merged.

Return Value

The function returns a result of type INT, representing the cardinality of the merged Bitmap.

Example

Assume there is a table bitmap_column_expr_test2 with a column z that stores multiple intermediate Bitmap data. The query returns the cardinality of the merged Bitmap:

SELECT groupBitmapMerge(bitmapBuild(v)) AS res
FROM VALUES (array(1,2,3,4,5,6,7,8,9,10)), (array(6,7,8,9,10,11,12,13,14,15)), (array(2,4,6,8,10,12)) AS t(v);
+-----+
| res |
+-----+
| 15  |
+-----+

Notes

1. Input Type: Ensure the input bitmap_state is of type BITMAP.
2. Performance Optimization: This function is highly efficient for large-scale datasets. However, performance impact should still be considered if the data volume is extremely large.