mirror of https://github.com/postgres/postgres
We've measured 5% performance improvement, and this arranges to benefit automatically from future optimizations to the read_stream subsystem. The area lacked test coverage, so close that gap. Nazir Bilal Yavuz Discussion: https://postgr.es/m/CAN55FZ1_Ru3XpMgTwsU67FTH2fs_FrRROmb7x6zs+F44QBEiww@mail.gmail.com Discussion: https://postgr.es/m/CAEudQAozv3wTY5TV2t29JcwPydbmKbiWQkZD42S2OgzdixPMDQ@mail.gmail.compull/177/head
Noah Misch
10 months ago
parent
52c707483c
commit
65c310b310
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# Copyright (c) 2021-2024, PostgreSQL Global Development Group |
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|
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# Check that pg_check_visible() and pg_check_frozen() report correct TIDs for |
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# corruption. |
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use strict; |
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use warnings FATAL => 'all'; |
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use File::Copy; |
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use PostgreSQL::Test::Cluster; |
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use PostgreSQL::Test::Utils; |
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use Test::More; |
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|
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my $node = PostgreSQL::Test::Cluster->new('main'); |
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$node->init; |
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# Anything holding a snapshot, including auto-analyze of pg_proc, could stop |
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# VACUUM from updating the visibility map. |
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$node->append_conf('postgresql.conf', 'autovacuum=off'); |
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$node->start; |
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|
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my $blck_size = $node->safe_psql("postgres", "SHOW block_size;"); |
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|
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# Create a sample table with at least 10 pages and then run VACUUM. 10 is |
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# selected manually as it is big enough to select 5 random tuples from the |
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# relation. |
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$node->safe_psql( |
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'postgres', qq( |
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CREATE EXTENSION pg_visibility; |
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CREATE TABLE corruption_test |
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WITH (autovacuum_enabled = false) AS |
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SELECT |
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i, |
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repeat('a', 10) AS data |
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FROM |
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generate_series(1, $blck_size) i; |
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VACUUM (FREEZE, DISABLE_PAGE_SKIPPING) corruption_test; |
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)); |
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|
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# VACUUM is run, it is safe to get the number of pages. |
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my $npages = $node->safe_psql( |
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"postgres", |
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"SELECT relpages FROM pg_class |
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WHERE relname = 'corruption_test';" |
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); |
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ok($npages >= 10, 'table has at least 10 pages'); |
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|
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my $file = $node->safe_psql("postgres", |
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"SELECT pg_relation_filepath('corruption_test');"); |
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|
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# Delete the first block to make sure that it will be skipped as it is |
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# not visible nor frozen. |
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$node->safe_psql( |
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"postgres", |
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"DELETE FROM corruption_test |
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WHERE (ctid::text::point)[0] = 0;" |
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); |
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|
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# Copy visibility map. |
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$node->stop; |
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my $vm_file = $node->data_dir . '/' . $file . '_vm'; |
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copy("$vm_file", "${vm_file}_temp"); |
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$node->start; |
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|
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# Select 5 random tuples that are starting from the second block of the |
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# relation. The first block is skipped because it is deleted above. |
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my $tuples = $node->safe_psql( |
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"postgres", |
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"SELECT ctid FROM ( |
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SELECT ctid FROM corruption_test |
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WHERE (ctid::text::point)[0] != 0 |
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ORDER BY random() LIMIT 5) |
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ORDER BY ctid ASC;" |
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); |
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|
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# Do the changes below to use tuples in the query. |
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# "\n" -> "," |
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# "(" -> "'(" |
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# ")" -> ")'" |
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(my $tuples_query = $tuples) =~ s/\n/,/g; |
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$tuples_query =~ s/\(/\'\(/g; |
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$tuples_query =~ s/\)/\)\'/g; |
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|
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$node->safe_psql( |
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"postgres", |
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"DELETE FROM corruption_test |
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WHERE ctid in ($tuples_query);" |
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); |
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|
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# Overwrite visibility map with the old one. |
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$node->stop; |
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move("${vm_file}_temp", "$vm_file"); |
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$node->start; |
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|
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my $result = $node->safe_psql( |
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"postgres", |
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"SELECT DISTINCT t_ctid |
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FROM pg_check_visible('corruption_test') |
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ORDER BY t_ctid ASC;" |
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); |
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is($result, $tuples, 'pg_check_visible must report tuples as corrupted'); |
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|
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$result = $node->safe_psql( |
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"postgres", |
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"SELECT DISTINCT t_ctid |
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FROM pg_check_frozen('corruption_test') |
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ORDER BY t_ctid ASC;" |
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); |
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is($result, $tuples, 'pg_check_frozen must report tuples as corrupted'); |
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|
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$node->stop; |
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done_testing(); |
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