INSERTINTO tst SELECT i%10, substr(encode(sha256(i::text::bytea), 'hex'), 1, 1) FROM generate_series(1,2000) i; CREATEINDEX bloomidx ON tst USING bloom (i, t) WITH (col1 = 3); ALTERINDEX bloomidx SET (length=80);
SET enable_seqscan=on; SET enable_bitmapscan=off; SET enable_indexscan=off;
SELECT count(*) FROM tst WHERE i = 7; SELECT count(*) FROM tst WHERE t = '5'; SELECT count(*) FROM tst WHERE i = 7AND t = '5';
SET enable_seqscan=off; SET enable_bitmapscan=on; SET enable_indexscan=on;
EXPLAIN (COSTS OFF) SELECT count(*) FROM tst WHERE i = 7; EXPLAIN (COSTS OFF) SELECT count(*) FROM tst WHERE t = '5'; EXPLAIN (COSTS OFF) SELECT count(*) FROM tst WHERE i = 7AND t = '5';
SELECT count(*) FROM tst WHERE i = 7; SELECT count(*) FROM tst WHERE t = '5'; SELECT count(*) FROM tst WHERE i = 7AND t = '5';
SELECT count(*) FROM tst WHERE i = 7; SELECT count(*) FROM tst WHERE t = '5'; SELECT count(*) FROM tst WHERE i = 7AND t = '5';
DELETEFROM tst WHERE i > 1OR t = '5';
VACUUM tst; INSERTINTO tst SELECT i%10, substr(encode(sha256(i::text::bytea), 'hex'), 1, 1) FROM generate_series(1,2000) i;
SELECT count(*) FROM tst WHERE i = 7; SELECT count(*) FROM tst WHERE t = '5'; SELECT count(*) FROM tst WHERE i = 7AND t = '5';
VACUUM FULL tst;
SELECT count(*) FROM tst WHERE i = 7; SELECT count(*) FROM tst WHERE t = '5'; SELECT count(*) FROM tst WHERE i = 7AND t = '5';
-- Try an unlogged table too
CREATE UNLOGGED TABLE tstu (
i int4,
t text
);
INSERTINTO tstu SELECT i%10, substr(encode(sha256(i::text::bytea), 'hex'), 1, 1) FROM generate_series(1,2000) i; CREATEINDEX bloomidxu ON tstu USING bloom (i, t) WITH (col2 = 4);
SET enable_seqscan=off; SET enable_bitmapscan=on; SET enable_indexscan=on;
EXPLAIN (COSTS OFF) SELECT count(*) FROM tstu WHERE i = 7; EXPLAIN (COSTS OFF) SELECT count(*) FROM tstu WHERE t = '5'; EXPLAIN (COSTS OFF) SELECT count(*) FROM tstu WHERE i = 7AND t = '5';
SELECT count(*) FROM tstu WHERE i = 7; SELECT count(*) FROM tstu WHERE t = '5'; SELECT count(*) FROM tstu WHERE i = 7AND t = '5';
-- Run amvalidator function on our opclasses SELECT opcname, amvalidate(opc.oid) FROM pg_opclass opc JOIN pg_am am ON am.oid = opcmethod WHERE amname = 'bloom' ORDERBY1;
-- -- relation options -- DROPINDEX bloomidx; CREATEINDEX bloomidx ON tst USING bloom (i, t) WITH (length=7, col1=4); SELECT reloptions FROM pg_class WHERE oid = 'bloomidx'::regclass; -- check for min and max values
\set VERBOSITY terse CREATEINDEX bloomidx2 ON tst USING bloom (i, t) WITH (length=0); CREATEINDEX bloomidx2 ON tst USING bloom (i, t) WITH (col1=0);
Messung V0.5 in Prozent
¤ Dauer der Verarbeitung: 0.14 Sekunden
(vorverarbeitet am 2026-08-08)
¤
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