Help Center/ GaussDB(DWS)/ SQL Syntax Reference/ SQL Syntax Reference (8.3.0.x)/ Functions and Operators/ Bitmap Functions and Operators/ Roaring Bitmap Aggregation Functions
Updated on 2024-09-03 GMT+08:00
View PDF
Share

Roaring Bitmap Aggregation Functions

Since 8.1.3, GaussDB(DWS) supports efficient bitmap processing functions and operators, which can be used in user profiling and precision marketing, greatly improving query performance.

rb_build_agg(int)

Description: Aggregates int values in a group into a RoaringBitmap value.

Return type: RoaringBitmap

Example:

1
2
3
4
5
6
 
CREATE TABLE t1 (a int ,b int);
NOTICE:  The 'DISTRIBUTE BY' clause is not specified. Using round-robin as the distribution mode by default.
HINT:  Please use 'DISTRIBUTE BY' clause to specify suitable data distribution column.
CREATE TABLE
INSERT INTO t1 SELECT generate_series(1,10),generate_series(1,20,2);
INSERT 0 10

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
 
SELECT rb_iterate(rb_build_agg(b)) FROM t1;
rb_iterate
------------
1
3
5
7
9
11
13
15
17
19
(10 rows)

rb_and_agg(roaringbitmap)

Description: Aggregates data of the Roaring bitmaps in a group into a Roaring bitmap set based on the INTERSECT operation.

Example:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
 
CREATE TABLE r1(a int ,b roaringbitmap);
INSERT INTO r1 SELECT a, rb_build_agg(b) FROM t1 GROUP BY a;
INSERT INTO t1 SELECT generate_series(1,10),generate_series(1,20,4);
INSERT INTO r1 SELECT a, rb_build_agg(b) FROM t1 GROUP BY a;
SELECT a, rb_to_array(rb_and_agg(b)) FROM r1 GROUP BY a ORDER BY a;
 a  | rb_to_array
----+-------------
 1  | {1}
 2  | {3}
 3  | {5}
 4  | {7}
 5  | {9}
 6  | {11}
 7  | {13}
 8  | {15}
 9  | {17}
10  | {19}
(10 rows)

rb_or_agg(roaringbitmap)

Description: Combines Roaring bitmaps in a group into one Roaring bitmap based on the UNION logic.

Example:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
 
SELECT a, rb_to_array(rb_or_agg(b)) FROM r1 GROUP BY a ORDER BY a;
 a  | rb_to_array
----+-------------
 1  | {1}
 2  | {3,5}
 3  | {5,9}
 4  | {7,13}
 5  | {9,17}
 6  | {1,11}
 7  | {5,13}
 8  | {9,15}
 9  | {13,17}
 10 | {17,19}
(10 rows)

rb_xor_agg(roaringbitmap)

Description: Combines Roaring bitmaps in a group into one Roaring bitmap based on the XOR logic.

Example:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
 
SELECT a, rb_to_array(rb_xor_agg(b)) FROM r1 GROUP BY a ORDER BY a;
a   | rb_to_array
----+-------------
 1  | {}
 2  | {5}
 3  | {9}
 4  | {13}
 5  | {17}
 6  | {1}
 7  | {5}
 8  | {9}
 9  | {13}
 10 | {17}
(10 rows)

rb_and_cardinality_agg(roaringbitmap)

Description: Cardinality of Roaring bitmaps in a group calculated based on INTERSECT.

Return type: int

Example:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
 
SELECT a, rb_and_cardinality_agg(b) FROM r1 GROUP BY a ORDER BY 1;
 a  | rb_and_cardinality_agg
----+------------------------
 1  |                      1
 2  |                      1
 3  |                      1
 4  |                      1
 5  |                      1
 6  |                      1
 7  |                      1
 8  |                      1
 9  |                      1
 10 |                      1
(10 rows)

rb_or_cardinality_agg(roaringbitmap)

Description: Cardinality of Roaring bitmaps in a group calculated based on UNION.

Example:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
 
SELECT a, rb_or_cardinality_agg(b) FROM r1 GROUP BY a ORDER BY 1;
 a  | rb_or_cardinality_agg
----+-----------------------
 1  |                     1
 2  |                     2
 3  |                     2
 4  |                     2
 5  |                     2
 6  |                     2
 7  |                     2
 8  |                     2
 9  |                     2
 10 |                     2
(10 rows)

rb_xor_cardinality_agg(roaringbitmap)

Description: Cardinality of Roaring bitmaps in a group calculated based on XOR.

Example:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
 
SELECT a, rb_xor_cardinality_agg(b) FROM r1 GROUP BY a ORDER BY 1;
 a  | rb_xor_cardinality_agg
----+------------------------
 1  |                      0
 2  |                      1
 3  |                      1
 4  |                      1
 5  |                      1
 6  |                      1
 7  |                      1
 8  |                      1
 9  |                      1
 10 |                      1
(10 rows)