123 lines
2.4 KiB
Plaintext
123 lines
2.4 KiB
Plaintext
|
CREATE EXTENSION bloom;
|
||
|
CREATE TABLE tst (
|
||
|
i int4,
|
||
|
t text
|
||
|
);
|
||
|
INSERT INTO tst SELECT i%10, substr(md5(i::text), 1, 1) FROM generate_series(1,100000) i;
|
||
|
CREATE INDEX bloomidx ON tst USING bloom (i, t) WITH (col1 = 3);
|
||
|
SET enable_seqscan=on;
|
||
|
SET enable_bitmapscan=off;
|
||
|
SET enable_indexscan=off;
|
||
|
SELECT count(*) FROM tst WHERE i = 7;
|
||
|
count
|
||
|
-------
|
||
|
10000
|
||
|
(1 row)
|
||
|
|
||
|
SELECT count(*) FROM tst WHERE t = '5';
|
||
|
count
|
||
|
-------
|
||
|
6264
|
||
|
(1 row)
|
||
|
|
||
|
SELECT count(*) FROM tst WHERE i = 7 AND t = '5';
|
||
|
count
|
||
|
-------
|
||
|
588
|
||
|
(1 row)
|
||
|
|
||
|
SET enable_seqscan=off;
|
||
|
SET enable_bitmapscan=on;
|
||
|
SET enable_indexscan=on;
|
||
|
EXPLAIN (COSTS OFF) SELECT count(*) FROM tst WHERE i = 7;
|
||
|
QUERY PLAN
|
||
|
-------------------------------------------
|
||
|
Aggregate
|
||
|
-> Bitmap Heap Scan on tst
|
||
|
Recheck Cond: (i = 7)
|
||
|
-> Bitmap Index Scan on bloomidx
|
||
|
Index Cond: (i = 7)
|
||
|
(5 rows)
|
||
|
|
||
|
EXPLAIN (COSTS OFF) SELECT count(*) FROM tst WHERE t = '5';
|
||
|
QUERY PLAN
|
||
|
-------------------------------------------
|
||
|
Aggregate
|
||
|
-> Bitmap Heap Scan on tst
|
||
|
Recheck Cond: (t = '5'::text)
|
||
|
-> Bitmap Index Scan on bloomidx
|
||
|
Index Cond: (t = '5'::text)
|
||
|
(5 rows)
|
||
|
|
||
|
EXPLAIN (COSTS OFF) SELECT count(*) FROM tst WHERE i = 7 AND t = '5';
|
||
|
QUERY PLAN
|
||
|
---------------------------------------------------------
|
||
|
Aggregate
|
||
|
-> Bitmap Heap Scan on tst
|
||
|
Recheck Cond: ((i = 7) AND (t = '5'::text))
|
||
|
-> Bitmap Index Scan on bloomidx
|
||
|
Index Cond: ((i = 7) AND (t = '5'::text))
|
||
|
(5 rows)
|
||
|
|
||
|
SELECT count(*) FROM tst WHERE i = 7;
|
||
|
count
|
||
|
-------
|
||
|
10000
|
||
|
(1 row)
|
||
|
|
||
|
SELECT count(*) FROM tst WHERE t = '5';
|
||
|
count
|
||
|
-------
|
||
|
6264
|
||
|
(1 row)
|
||
|
|
||
|
SELECT count(*) FROM tst WHERE i = 7 AND t = '5';
|
||
|
count
|
||
|
-------
|
||
|
588
|
||
|
(1 row)
|
||
|
|
||
|
DELETE FROM tst;
|
||
|
INSERT INTO tst SELECT i%10, substr(md5(i::text), 1, 1) FROM generate_series(1,100000) i;
|
||
|
VACUUM ANALYZE tst;
|
||
|
SELECT count(*) FROM tst WHERE i = 7;
|
||
|
count
|
||
|
-------
|
||
|
10000
|
||
|
(1 row)
|
||
|
|
||
|
SELECT count(*) FROM tst WHERE t = '5';
|
||
|
count
|
||
|
-------
|
||
|
6264
|
||
|
(1 row)
|
||
|
|
||
|
SELECT count(*) FROM tst WHERE i = 7 AND t = '5';
|
||
|
count
|
||
|
-------
|
||
|
588
|
||
|
(1 row)
|
||
|
|
||
|
VACUUM FULL tst;
|
||
|
SELECT count(*) FROM tst WHERE i = 7;
|
||
|
count
|
||
|
-------
|
||
|
10000
|
||
|
(1 row)
|
||
|
|
||
|
SELECT count(*) FROM tst WHERE t = '5';
|
||
|
count
|
||
|
-------
|
||
|
6264
|
||
|
(1 row)
|
||
|
|
||
|
SELECT count(*) FROM tst WHERE i = 7 AND t = '5';
|
||
|
count
|
||
|
-------
|
||
|
588
|
||
|
(1 row)
|
||
|
|
||
|
RESET enable_seqscan;
|
||
|
RESET enable_bitmapscan;
|
||
|
RESET enable_indexscan;
|