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f0d1127595
32d3ed816 added the "path" column to pg_backend_memory_contexts to allow
a stable method of obtaining the parent MemoryContext of a given row in
the view. Using the "path" column is now the preferred method of
obtaining the parent row.
Previously, any queries which were self-joining to this view using the
"name" and "parent" columns could get incorrect results due to the fact
that names are not unique. Here we aim to explicitly break such queries
so that they can be corrected and use the "path" column instead.
It is possible that there are more innocent users of the parent column
that just need an indication of the parent and having to write out a
self-joining CTE may be an unnecessary hassle for those cases. Let's
remove the column for now and see if anyone comes back with any
complaints. This does seem like a good time to attempt to get rid of
the column as we still have around 1 year to revert this if someone comes
back with a valid complaint. Plus this view is new to v14 and is quite
niche, so perhaps not many people will be affected.
Author: Melih Mutlu <m.melihmutlu@gmail.com>
Discussion: https://postgr.es/m/CAGPVpCT7NOe4fZXRL8XaoxHpSXYTu6GTpULT_3E-HT9hzjoFRA@mail.gmail.com
101 lines
4.2 KiB
PL/PgSQL
101 lines
4.2 KiB
PL/PgSQL
--
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-- Test assorted system views
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--
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-- This test is mainly meant to provide some code coverage for the
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-- set-returning functions that underlie certain system views.
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-- The output of most of these functions is very environment-dependent,
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-- so our ability to test with fixed expected output is pretty limited;
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-- but even a trivial check of count(*) will exercise the normal code path
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-- through the SRF.
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select count(*) >= 0 as ok from pg_available_extension_versions;
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select count(*) >= 0 as ok from pg_available_extensions;
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-- The entire output of pg_backend_memory_contexts is not stable,
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-- we test only the existence and basic condition of TopMemoryContext.
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select type, name, ident, level, total_bytes >= free_bytes
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from pg_backend_memory_contexts where level = 1;
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-- We can exercise some MemoryContext type stats functions. Most of the
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-- column values are too platform-dependant to display.
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-- Ensure stats from the bump allocator look sane. Bump isn't a commonly
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-- used context, but it is used in tuplesort.c, so open a cursor to keep
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-- the tuplesort alive long enough for us to query the context stats.
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begin;
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declare cur cursor for select left(a,10), b
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from (values(repeat('a', 512 * 1024),1),(repeat('b', 512),2)) v(a,b)
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order by v.a desc;
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fetch 1 from cur;
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select type, name, total_bytes > 0, total_nblocks, free_bytes > 0, free_chunks
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from pg_backend_memory_contexts where name = 'Caller tuples';
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rollback;
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-- Further sanity checks on pg_backend_memory_contexts. We expect
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-- CacheMemoryContext to have multiple children. Ensure that's the case.
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with contexts as (
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select * from pg_backend_memory_contexts
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)
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select count(*) > 1
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from contexts c1, contexts c2
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where c2.name = 'CacheMemoryContext'
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and c1.path[c2.level] = c2.path[c2.level];
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-- At introduction, pg_config had 23 entries; it may grow
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select count(*) > 20 as ok from pg_config;
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-- We expect no cursors in this test; see also portals.sql
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select count(*) = 0 as ok from pg_cursors;
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select count(*) >= 0 as ok from pg_file_settings;
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-- There will surely be at least one rule, with no errors.
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select count(*) > 0 as ok, count(*) FILTER (WHERE error IS NOT NULL) = 0 AS no_err
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from pg_hba_file_rules;
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-- There may be no rules, and there should be no errors.
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select count(*) >= 0 as ok, count(*) FILTER (WHERE error IS NOT NULL) = 0 AS no_err
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from pg_ident_file_mappings;
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-- There will surely be at least one active lock
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select count(*) > 0 as ok from pg_locks;
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-- We expect no prepared statements in this test; see also prepare.sql
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select count(*) = 0 as ok from pg_prepared_statements;
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-- See also prepared_xacts.sql
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select count(*) >= 0 as ok from pg_prepared_xacts;
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-- There will surely be at least one SLRU cache
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select count(*) > 0 as ok from pg_stat_slru;
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-- There must be only one record
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select count(*) = 1 as ok from pg_stat_wal;
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-- We expect no walreceiver running in this test
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select count(*) = 0 as ok from pg_stat_wal_receiver;
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-- This is to record the prevailing planner enable_foo settings during
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-- a regression test run.
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select name, setting from pg_settings where name like 'enable%';
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-- There are always wait event descriptions for various types. InjectionPoint
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-- may be present or absent, depending on history since last postmaster start.
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select type, count(*) > 0 as ok FROM pg_wait_events
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where type <> 'InjectionPoint' group by type order by type COLLATE "C";
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-- Test that the pg_timezone_names and pg_timezone_abbrevs views are
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-- more-or-less working. We can't test their contents in any great detail
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-- without the outputs changing anytime IANA updates the underlying data,
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-- but it seems reasonable to expect at least one entry per major meridian.
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-- (At the time of writing, the actual counts are around 38 because of
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-- zones using fractional GMT offsets, so this is a pretty loose test.)
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select count(distinct utc_offset) >= 24 as ok from pg_timezone_names;
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select count(distinct utc_offset) >= 24 as ok from pg_timezone_abbrevs;
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-- Let's check the non-default timezone abbreviation sets, too
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set timezone_abbreviations = 'Australia';
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select count(distinct utc_offset) >= 24 as ok from pg_timezone_abbrevs;
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set timezone_abbreviations = 'India';
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select count(distinct utc_offset) >= 24 as ok from pg_timezone_abbrevs;
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