Fix to increment the index scan counter for the bloom filter index
Masahiro Ikeda <ikedamsh@oss.nttdata.com>
From: Masahiro Ikeda <ikedamsh@oss.nttdata.com>
To: pgsql-hackers@postgresql.org
Date: 2024-11-12T10:01:47Z
Lists: pgsql-hackers
Attachments
- v1-0001-Modify-to-increment-the-index-scan-counter-for-Bl.patch (text/x-diff) patch v1-0001
Hi,
I noticed that the bloom filter index forgets to increment the index
scan counter
while reviewing the skip scan patch [1]. It seems this was simply
overlooked in
the implementation. What do you think?
# A test case:
## HEAD: 3f323eba89fb
CREATE EXTENSION bloom ;
CREATE TABLE tbloom AS
SELECT
(random() * 1000000)::int as i1,
(random() * 1000000)::int as i2,
(random() * 1000000)::int as i3,
(random() * 1000000)::int as i4,
(random() * 1000000)::int as i5,
(random() * 1000000)::int as i6
FROM
generate_series(1,10000000);
CREATE INDEX bloomidx ON tbloom USING bloom (i1, i2, i3, i4, i5, i6);
ANALYZE;
psql=# SELECT * FROM pg_stat_user_indexes ;
-[ RECORD 1 ]-+---------
relid | 16384
indexrelid | 16398
schemaname | public
relname | tbloom
indexrelname | bloomidx
idx_scan | 0
last_idx_scan |
idx_tup_read | 0
idx_tup_fetch | 0
psql=# SET enable_seqscan = off;
psql=# EXPLAIN ANALYZE SELECT * FROM tbloom WHERE i2 = 898732 AND i5 =
123451;
postgres=# SELECT * FROM pg_stat_user_indexes ;
-[ RECORD 1 ]-+---------
relid | 16384
indexrelid | 16398
schemaname | public
relname | tbloom
indexrelname | bloomidx
idx_scan | 0 # was not incremented
last_idx_scan | #
idx_tup_read | 2362 # was incremented. It indicates
that an index scan was executed
idx_tup_fetch | 0
## HEAD with the v1 patch
-- after EXPLAIN ANALYZE ...
postgres=# SELECT * FROM pg_stat_user_indexes ;
-[ RECORD 1 ]-+------------------------------
relid | 16395
indexrelid | 16398
schemaname | public
relname | tbloom
indexrelname | bloomidx
idx_scan | 1 # was incremented
too
last_idx_scan | 2024-11-12 18:15:39.270747+09 #
idx_tup_read | 2503 #
idx_tup_fetch | 0
[1]
https://www.postgresql.org/message-id/flat/CAH2-Wz%3DM_8UCPpD5GQuJXmQZ6xePwhVSss38TmkBAwic12VvCg%40mail.gmail.com#ffef7ecf393d0008c5ded2d2184a71f9
Regards,
--
Masahiro Ikeda
NTT DATA CORPORATION
Commits
-
Count contrib/bloom index scans in pgstat view.
- 93063e2e429b 18.0 landed
- 7af6d13061ee 17.2 landed
- 05aac2e83752 16.6 landed
- 16a2bb0793ac 15.10 landed
- 2a30b6836db4 14.15 landed
- e493ea866ebb 13.18 landed