From 55f5fbc413e83968f9ac6a9fdc1b1b4a720b3d58 Mon Sep 17 00:00:00 2001 From: Amit Kapila Date: Wed, 15 Apr 2020 08:43:45 +0530 Subject: [PATCH v5] Fix the usage of parallel and full options of vacuum command. Earlier we were inconsistent in allowing the usage of parallel and full options. Change it such that we disallow them only when they are combined in a way that we don't support. In passing, improve the comments in some of the existing tests of parallel vacuum. Reported-by: Tushar Ahuja Author: Justin Pryzby, Amit Kapila Reviewed-by: Sawada Masahiko, Michael Paquier, Mahendra Singh Thalor and Amit Kapila Discussion: https://postgr.es/m/58c8d171-e665-6fa3-a9d3-d9423b694dae%40enterprisedb.com --- doc/src/sgml/ref/vacuum.sgml | 32 ++++++++++++++++---------------- src/backend/commands/vacuum.c | 6 ++---- src/test/regress/expected/vacuum.out | 6 ++++-- src/test/regress/sql/vacuum.sql | 5 ++++- 4 files changed, 26 insertions(+), 23 deletions(-) diff --git a/doc/src/sgml/ref/vacuum.sgml b/doc/src/sgml/ref/vacuum.sgml index 442977a..775b665 100644 --- a/doc/src/sgml/ref/vacuum.sgml +++ b/doc/src/sgml/ref/vacuum.sgml @@ -235,22 +235,22 @@ VACUUM [ FULL ] [ FREEZE ] [ VERBOSE ] [ ANALYZE ] [ integer background workers (for the details of each vacuum phase, please - refer to ). If the - PARALLEL option is omitted, then the number of workers - is determined based on the number of indexes that support parallel vacuum - operation on the relation, and is further limited by . - An index can participate in parallel vacuum if and only if the size - of the index is more than . - Please note that it is not guaranteed that the number of parallel workers - specified in integer will - be used during execution. It is possible for a vacuum to run with fewer - workers than specified, or even with no workers at all. Only one worker - can be used per index. So parallel workers are launched only when there - are at least 2 indexes in the table. Workers for - vacuum are launched before the start of each phase and exit at the end of - the phase. These behaviors might change in a future release. This - option can't be used with the FULL option. + refer to ). In plain VACUUM + (without FULL), if the PARALLEL option + is omitted, then the number of workers is determined based on the number of + indexes that support parallel vacuum operation on the relation and is further + limited by . An index + can participate in parallel vacuum if and only if the size of the index is + more than . Please note + that it is not guaranteed that the number of parallel workers specified in + integer will be used during + execution. It is possible for a vacuum to run with fewer workers than + specified, or even with no workers at all. Only one worker can be used per + index. So parallel workers are launched only when there are at least + 2 indexes in the table. Workers for vacuum are launched + before the start of each phase and exit at the end of the phase. These + behaviors might change in a future release. This option can't be used with + the FULL option. diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c index 495ac23..5a110ed 100644 --- a/src/backend/commands/vacuum.c +++ b/src/backend/commands/vacuum.c @@ -104,7 +104,6 @@ ExecVacuum(ParseState *pstate, VacuumStmt *vacstmt, bool isTopLevel) bool freeze = false; bool full = false; bool disable_page_skipping = false; - bool parallel_option = false; ListCell *lc; /* Set default value */ @@ -145,7 +144,6 @@ ExecVacuum(ParseState *pstate, VacuumStmt *vacstmt, bool isTopLevel) params.truncate = get_vacopt_ternary_value(opt); else if (strcmp(opt->defname, "parallel") == 0) { - parallel_option = true; if (opt->arg == NULL) { ereport(ERROR, @@ -199,10 +197,10 @@ ExecVacuum(ParseState *pstate, VacuumStmt *vacstmt, bool isTopLevel) !(params.options & (VACOPT_FULL | VACOPT_FREEZE))); Assert(!(params.options & VACOPT_SKIPTOAST)); - if ((params.options & VACOPT_FULL) && parallel_option) + if ((params.options & VACOPT_FULL) && params.nworkers > 0) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), - errmsg("cannot specify both FULL and PARALLEL options"))); + errmsg("VACUUM FULL cannot be performed in parallel"))); /* * Make sure VACOPT_ANALYZE is specified if any column lists are present. diff --git a/src/test/regress/expected/vacuum.out b/src/test/regress/expected/vacuum.out index 0cfe28e..736c2f6 100644 --- a/src/test/regress/expected/vacuum.out +++ b/src/test/regress/expected/vacuum.out @@ -115,15 +115,17 @@ LINE 1: VACUUM (PARALLEL -1) pvactst; ^ VACUUM (PARALLEL 2, INDEX_CLEANUP FALSE) pvactst; VACUUM (PARALLEL 2, FULL TRUE) pvactst; -- error, cannot use both PARALLEL and FULL -ERROR: cannot specify both FULL and PARALLEL options +ERROR: VACUUM FULL cannot be performed in parallel VACUUM (PARALLEL) pvactst; -- error, cannot use PARALLEL option without parallel degree ERROR: parallel option requires a value between 0 and 1024 LINE 1: VACUUM (PARALLEL) pvactst; ^ +-- Test different combinations of parallel and full options for temporary tables CREATE TEMPORARY TABLE tmp (a int PRIMARY KEY); CREATE INDEX tmp_idx1 ON tmp (a); -VACUUM (PARALLEL 1) tmp; -- disables parallel vacuum option +VACUUM (PARALLEL 1, FULL FALSE) tmp; -- parallel vacuum disabled for temp tables WARNING: disabling parallel option of vacuum on "tmp" --- cannot vacuum temporary tables in parallel +VACUUM (PARALLEL 0, FULL TRUE) tmp; -- can specify parallel disabled (even though that's implied by FULL) RESET min_parallel_index_scan_size; DROP TABLE pvactst; -- INDEX_CLEANUP option diff --git a/src/test/regress/sql/vacuum.sql b/src/test/regress/sql/vacuum.sql index cf741f7..84dee8c 100644 --- a/src/test/regress/sql/vacuum.sql +++ b/src/test/regress/sql/vacuum.sql @@ -100,9 +100,12 @@ VACUUM (PARALLEL -1) pvactst; -- error VACUUM (PARALLEL 2, INDEX_CLEANUP FALSE) pvactst; VACUUM (PARALLEL 2, FULL TRUE) pvactst; -- error, cannot use both PARALLEL and FULL VACUUM (PARALLEL) pvactst; -- error, cannot use PARALLEL option without parallel degree + +-- Test different combinations of parallel and full options for temporary tables CREATE TEMPORARY TABLE tmp (a int PRIMARY KEY); CREATE INDEX tmp_idx1 ON tmp (a); -VACUUM (PARALLEL 1) tmp; -- disables parallel vacuum option +VACUUM (PARALLEL 1, FULL FALSE) tmp; -- parallel vacuum disabled for temp tables +VACUUM (PARALLEL 0, FULL TRUE) tmp; -- can specify parallel disabled (even though that's implied by FULL) RESET min_parallel_index_scan_size; DROP TABLE pvactst; -- 1.8.3.1