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a1bc4d3590
The number of relation pages is tricky to get right in a portable way, particularly across 32b and 64b builds, but checking after the existence of the FSM and if there is any space available space should be stable enough with a minimal number of tuples involved. This commit introduces checks on a table with some btree, BRIN and hash indexes, as a first attempt. Author: Dong Wook Lee, Fabrízio de Royes Mello, Michael Paquier Discussion: https://postgr.es/m/CAAcByaJ5KW3bd7fJr=jPEyK8M_UzXJFHHBVuOcBe+JHD8txRyQ@mail.gmail.com
86 lines
2.8 KiB
Plaintext
86 lines
2.8 KiB
Plaintext
CREATE EXTENSION pg_freespacemap;
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CREATE TABLE freespace_tab (c1 int) WITH (autovacuum_enabled = off);
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CREATE INDEX freespace_brin ON freespace_tab USING brin (c1);
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CREATE INDEX freespace_btree ON freespace_tab USING btree (c1);
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CREATE INDEX freespace_hash ON freespace_tab USING hash (c1);
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-- report all the sizes of the FSMs for all the relation blocks.
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WITH rel AS (SELECT oid::regclass AS id FROM pg_class WHERE relname ~ 'freespace')
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SELECT rel.id, fsm.blkno, (fsm.avail > 0) AS is_avail
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FROM rel, LATERAL pg_freespace(rel.id) AS fsm
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ORDER BY 1, 2;
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id | blkno | is_avail
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-----------------+-------+----------
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freespace_brin | 0 | f
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freespace_brin | 1 | f
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freespace_brin | 2 | t
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freespace_btree | 0 | f
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freespace_hash | 0 | f
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freespace_hash | 1 | f
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freespace_hash | 2 | f
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freespace_hash | 3 | f
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freespace_hash | 4 | f
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freespace_hash | 5 | f
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freespace_hash | 6 | f
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freespace_hash | 7 | f
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freespace_hash | 8 | f
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freespace_hash | 9 | f
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(14 rows)
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INSERT INTO freespace_tab VALUES (1);
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VACUUM freespace_tab;
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WITH rel AS (SELECT oid::regclass AS id FROM pg_class WHERE relname ~ 'freespace')
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SELECT rel.id, fsm.blkno, (fsm.avail > 0) AS is_avail
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FROM rel, LATERAL pg_freespace(rel.id) AS fsm
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ORDER BY 1, 2;
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id | blkno | is_avail
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-----------------+-------+----------
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freespace_tab | 0 | t
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freespace_brin | 0 | f
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freespace_brin | 1 | f
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freespace_brin | 2 | t
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freespace_btree | 0 | f
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freespace_btree | 1 | f
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freespace_hash | 0 | f
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freespace_hash | 1 | f
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freespace_hash | 2 | f
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freespace_hash | 3 | f
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freespace_hash | 4 | f
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freespace_hash | 5 | f
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freespace_hash | 6 | f
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freespace_hash | 7 | f
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freespace_hash | 8 | f
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freespace_hash | 9 | f
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(16 rows)
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DELETE FROM freespace_tab;
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VACUUM freespace_tab;
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WITH rel AS (SELECT oid::regclass AS id FROM pg_class WHERE relname ~ 'freespace')
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SELECT rel.id, fsm.blkno, (fsm.avail > 0) AS is_avail
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FROM rel, LATERAL pg_freespace(rel.id) AS fsm
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ORDER BY 1, 2;
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id | blkno | is_avail
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-----------------+-------+----------
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freespace_brin | 0 | f
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freespace_brin | 1 | f
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freespace_brin | 2 | t
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freespace_btree | 0 | f
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freespace_btree | 1 | f
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freespace_hash | 0 | f
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freespace_hash | 1 | f
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freespace_hash | 2 | f
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freespace_hash | 3 | f
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freespace_hash | 4 | f
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freespace_hash | 5 | f
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freespace_hash | 6 | f
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freespace_hash | 7 | f
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freespace_hash | 8 | f
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freespace_hash | 9 | f
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(15 rows)
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-- failures with incorrect block number
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SELECT * FROM pg_freespace('freespace_tab', -1);
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ERROR: invalid block number
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SELECT * FROM pg_freespace('freespace_tab', 4294967295);
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ERROR: invalid block number
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DROP TABLE freespace_tab;
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