From b5f9a66b263506e4981d1bbaaf955336cba16729 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Tue, 4 Mar 2025 11:07:47 -0500 Subject: [PATCH v2.6 15/34] tests: Expand temp table tests to some pin related matters Author: Reviewed-By: Discussion: https://postgr.es/m/ Backpatch: --- src/test/regress/expected/temp.out | 156 +++++++++++++++++++++++++++++ src/test/regress/parallel_schedule | 2 +- src/test/regress/sql/temp.sql | 107 ++++++++++++++++++++ 3 files changed, 264 insertions(+), 1 deletion(-) diff --git a/src/test/regress/expected/temp.out b/src/test/regress/expected/temp.out index 2a246a7e123..91fe519b1cc 100644 --- a/src/test/regress/expected/temp.out +++ b/src/test/regress/expected/temp.out @@ -410,3 +410,159 @@ SELECT current_schema() ~ 'pg_temp' AS is_temp_schema; PREPARE TRANSACTION 'twophase_search'; ERROR: cannot PREPARE a transaction that has operated on temporary objects +-- Tests to verify we recover correctly from exhausting buffer pins and +-- related matters. +-- use lower possible buffer limit to make the test cheaper +\c +SET temp_buffers = 100; +CREATE TEMPORARY TABLE test_temp(a int not null unique, b TEXT not null, cnt int not null); +INSERT INTO test_temp SELECT generate_series(1, 10000) as id, repeat('a', 200), 0; +-- should be at least 2x as large than temp_buffers +SELECT pg_relation_size('test_temp') / current_setting('block_size')::int8 > 200; + ?column? +---------- + t +(1 row) + +-- Don't want cursor names and plpgsql function lines in the error messages +\set VERBOSITY terse +/* helper function to create cursors for each page in [p_start, p_end] */ +CREATE FUNCTION test_temp_pin(p_start int, p_end int) +RETURNS void +LANGUAGE plpgsql +AS $f$ + DECLARE + cursorname text; + query text; + BEGIN + FOR i IN p_start..p_end LOOP + cursorname = 'c_'||i; + query = format($q$DECLARE %I CURSOR FOR SELECT ctid FROM test_temp WHERE ctid >= '( %s, 1)'::tid $q$, cursorname, i); + EXECUTE query; + EXECUTE 'FETCH NEXT FROM '||cursorname; + -- for test development + -- RAISE NOTICE '%: %', cursorname, query; + END LOOP; + END; +$f$; +-- Test overflow of temp table buffers is handled correctly +BEGIN; +-- should work, below max +SELECT test_temp_pin(0, 9); + test_temp_pin +--------------- + +(1 row) + +-- should fail, too many buffers pinned +SELECT test_temp_pin(10, 105); +ERROR: no empty local buffer available +ROLLBACK; +BEGIN; +-- have some working cursors to test after errors +SELECT test_temp_pin(0, 9); + test_temp_pin +--------------- + +(1 row) + +FETCH NEXT FROM c_3; + ctid +------- + (3,2) +(1 row) + +-- exhaust buffer pins in subtrans, check things work after +SAVEPOINT rescue_me; +SELECT test_temp_pin(10, 105); +ERROR: no empty local buffer available +ROLLBACK TO SAVEPOINT rescue_me; +-- pre-subtrans cursors continue to work +FETCH NEXT FROM c_3; + ctid +------- + (3,3) +(1 row) + +-- new cursors with pins can be created after subtrans rollback +SELECT test_temp_pin(10, 95); + test_temp_pin +--------------- + +(1 row) + +-- Check that read streams deal with lower number of pins available +SELECT count(*), max(a) max_a, min(a) min_a, max(cnt) max_cnt FROM test_temp; + count | max_a | min_a | max_cnt +-------+-------+-------+--------- + 10000 | 10000 | 1 | 0 +(1 row) + +ROLLBACK; +-- Check that temp tables with existing cursors can't be dropped. +BEGIN; +SELECT test_temp_pin(0, 1); + test_temp_pin +--------------- + +(1 row) + +DROP TABLE test_temp; +ERROR: cannot DROP TABLE "test_temp" because it is being used by active queries in this session +COMMIT; +-- Check that temp tables with existing cursors can't be dropped. +BEGIN; +SELECT test_temp_pin(0, 1); + test_temp_pin +--------------- + +(1 row) + +TRUNCATE test_temp; +ERROR: cannot TRUNCATE "test_temp" because it is being used by active queries in this session +COMMIT; +-- Check that temp tables that are dropped in transaction that's rolled back +-- preserve buffer contents +SELECT count(*), max(a) max_a, min(a) min_a, max(cnt) max_cnt FROM test_temp; + count | max_a | min_a | max_cnt +-------+-------+-------+--------- + 10000 | 10000 | 1 | 0 +(1 row) + +INSERT INTO test_temp(a, b, cnt) VALUES (-1, '', 0); +BEGIN; +INSERT INTO test_temp(a, b, cnt) VALUES (-2, '', 0); +DROP TABLE test_temp; +ROLLBACK; +SELECT count(*), max(a) max_a, min(a) min_a, max(cnt) max_cnt FROM test_temp; + count | max_a | min_a | max_cnt +-------+-------+-------+--------- + 10001 | 10000 | -1 | 0 +(1 row) + +-- Check that temp table drop is transactional and preserves dirty +-- buffer contents +UPDATE test_temp SET cnt = cnt + 1 WHERE a = -1; +BEGIN; +DROP TABLE test_temp; +ROLLBACK; +SELECT count(*), max(a) max_a, min(a) min_a, max(cnt) max_cnt FROM test_temp; + count | max_a | min_a | max_cnt +-------+-------+-------+--------- + 10001 | 10000 | -1 | 1 +(1 row) + +-- Check that temp table truncation is transactional and preserves dirty +-- buffer contents +UPDATE test_temp SET cnt = cnt + 1 WHERE a = -1; +BEGIN; +TRUNCATE test_temp; +ROLLBACK; +SELECT count(*), max(a) max_a, min(a) min_a, max(cnt) max_cnt FROM test_temp; + count | max_a | min_a | max_cnt +-------+-------+-------+--------- + 10001 | 10000 | -1 | 2 +(1 row) + +-- cleanup +DROP FUNCTION test_temp_pin(int, int); diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule index 37b6d21e1f9..0a35f2f8f6a 100644 --- a/src/test/regress/parallel_schedule +++ b/src/test/regress/parallel_schedule @@ -108,7 +108,7 @@ test: json jsonb json_encoding jsonpath jsonpath_encoding jsonb_jsonpath sqljson # ---------- # Another group of parallel tests # with depends on create_misc -# NB: temp.sql does a reconnect which transiently uses 2 connections, +# NB: temp.sql does reconnects which transiently use 2 connections, # so keep this parallel group to at most 19 tests # ---------- test: plancache limit plpgsql copy2 temp domain rangefuncs prepare conversion truncate alter_table sequence polymorphism rowtypes returning largeobject with xml diff --git a/src/test/regress/sql/temp.sql b/src/test/regress/sql/temp.sql index 2a487a1ef7f..12091f968de 100644 --- a/src/test/regress/sql/temp.sql +++ b/src/test/regress/sql/temp.sql @@ -311,3 +311,110 @@ SET search_path TO 'pg_temp'; BEGIN; SELECT current_schema() ~ 'pg_temp' AS is_temp_schema; PREPARE TRANSACTION 'twophase_search'; + + +-- Tests to verify we recover correctly from exhausting buffer pins and +-- related matters. + +-- use lower possible buffer limit to make the test cheaper +\c +SET temp_buffers = 100; + +CREATE TEMPORARY TABLE test_temp(a int not null unique, b TEXT not null, cnt int not null); +INSERT INTO test_temp SELECT generate_series(1, 10000) as id, repeat('a', 200), 0; +-- should be at least 2x as large than temp_buffers +SELECT pg_relation_size('test_temp') / current_setting('block_size')::int8 > 200; + +-- Don't want cursor names and plpgsql function lines in the error messages +\set VERBOSITY terse + +/* helper function to create cursors for each page in [p_start, p_end] */ +CREATE FUNCTION test_temp_pin(p_start int, p_end int) +RETURNS void +LANGUAGE plpgsql +AS $f$ + DECLARE + cursorname text; + query text; + BEGIN + FOR i IN p_start..p_end LOOP + cursorname = 'c_'||i; + query = format($q$DECLARE %I CURSOR FOR SELECT ctid FROM test_temp WHERE ctid >= '( %s, 1)'::tid $q$, cursorname, i); + EXECUTE query; + EXECUTE 'FETCH NEXT FROM '||cursorname; + -- for test development + -- RAISE NOTICE '%: %', cursorname, query; + END LOOP; + END; +$f$; + + +-- Test overflow of temp table buffers is handled correctly +BEGIN; +-- should work, below max +SELECT test_temp_pin(0, 9); +-- should fail, too many buffers pinned +SELECT test_temp_pin(10, 105); +ROLLBACK; + +BEGIN; +-- have some working cursors to test after errors +SELECT test_temp_pin(0, 9); +FETCH NEXT FROM c_3; +-- exhaust buffer pins in subtrans, check things work after +SAVEPOINT rescue_me; +SELECT test_temp_pin(10, 105); +ROLLBACK TO SAVEPOINT rescue_me; +-- pre-subtrans cursors continue to work +FETCH NEXT FROM c_3; + +-- new cursors with pins can be created after subtrans rollback +SELECT test_temp_pin(10, 95); + +-- Check that read streams deal with lower number of pins available +SELECT count(*), max(a) max_a, min(a) min_a, max(cnt) max_cnt FROM test_temp; + +ROLLBACK; + + +-- Check that temp tables with existing cursors can't be dropped. +BEGIN; +SELECT test_temp_pin(0, 1); +DROP TABLE test_temp; +COMMIT; + +-- Check that temp tables with existing cursors can't be dropped. +BEGIN; +SELECT test_temp_pin(0, 1); +TRUNCATE test_temp; +COMMIT; + +-- Check that temp tables that are dropped in transaction that's rolled back +-- preserve buffer contents +SELECT count(*), max(a) max_a, min(a) min_a, max(cnt) max_cnt FROM test_temp; +INSERT INTO test_temp(a, b, cnt) VALUES (-1, '', 0); +BEGIN; +INSERT INTO test_temp(a, b, cnt) VALUES (-2, '', 0); +DROP TABLE test_temp; +ROLLBACK; +SELECT count(*), max(a) max_a, min(a) min_a, max(cnt) max_cnt FROM test_temp; + +-- Check that temp table drop is transactional and preserves dirty +-- buffer contents +UPDATE test_temp SET cnt = cnt + 1 WHERE a = -1; +BEGIN; +DROP TABLE test_temp; +ROLLBACK; +SELECT count(*), max(a) max_a, min(a) min_a, max(cnt) max_cnt FROM test_temp; + +-- Check that temp table truncation is transactional and preserves dirty +-- buffer contents +UPDATE test_temp SET cnt = cnt + 1 WHERE a = -1; +BEGIN; +TRUNCATE test_temp; +ROLLBACK; +SELECT count(*), max(a) max_a, min(a) min_a, max(cnt) max_cnt FROM test_temp; + + +-- cleanup +DROP FUNCTION test_temp_pin(int, int); -- 2.48.1.76.g4e746b1a31.dirty