From cef2b8d52c59168bf34c22bff0ed98fea7232981 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Mon, 6 Apr 2020 11:05:57 +0900 Subject: [PATCH] Preserve clustered index after rewrites with ALTER TABLE A table rewritten by ALTER TABLE would lose tracking of an index usable for CLUSTER. This setting is tracked by pg_index.indisclustered and is controlled by ALTER TABLE, so some extra work was needed to restore it properly. Note that ALTER TABLE only marks the index that can be used for clustering, and does not do the actual operation. Author: Amit Langote, Justin Pryzby Reviewed-by: Ibrar Ahmed, Michael Paquier Discussion: https://postgr.es/m/20200202161718.GI13621@telsasoft.com Backpatch-through: 9.5 --- src/backend/commands/tablecmds.c | 46 ++++++++++++++++++++++ src/backend/utils/cache/lsyscache.c | 23 +++++++++++ src/include/utils/lsyscache.h | 1 + src/test/regress/expected/alter_table.out | 48 +++++++++++++++++++++++ src/test/regress/sql/alter_table.sql | 25 ++++++++++++ 5 files changed, 143 insertions(+) diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index e99e16efbc0..375e035f4e5 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -174,6 +174,7 @@ typedef struct AlteredTableInfo List *changedIndexOids; /* OIDs of indexes to rebuild */ List *changedIndexDefs; /* string definitions of same */ char *replicaIdentityIndex; /* index to reset as REPLICA IDENTITY */ + char *clusterOnIndex; /* index to use for CLUSTER */ } AlteredTableInfo; /* Struct describing one new constraint to check in Phase 3 scan */ @@ -9437,6 +9438,21 @@ RememberReplicaIdentityForRebuilding(Oid indoid, AlteredTableInfo *tab) tab->replicaIdentityIndex = get_rel_name(indoid); } +/* + * Subroutine for ATExecAlterColumnType: remember any clustered index. + */ +static void +RememberClusterOnForRebuilding(Oid indoid, AlteredTableInfo *tab) +{ + if (!get_index_isclustered(indoid)) + return; + + if (tab->clusterOnIndex) + elog(ERROR, "relation %u has multiple clustered indexes", tab->relid); + + tab->clusterOnIndex = get_rel_name(indoid); +} + /* * Subroutine for ATExecAlterColumnType: remember that a constraint needs * to be rebuilt (which we might already know). @@ -9481,9 +9497,18 @@ RememberConstraintForRebuilding(Oid conoid, AlteredTableInfo *tab, defstring); } + /* + * For the index of a constraint, if any, remember if it is used for + * the table's replica identity or if it is a clustered index, so that + * ATPostAlterTypeCleanup() can queue up commands necessary to restore + * those properties. + */ indoid = get_constraint_index(conoid); if (OidIsValid(indoid)) + { RememberReplicaIdentityForRebuilding(indoid, tab); + RememberClusterOnForRebuilding(indoid, tab); + } } } @@ -9528,7 +9553,13 @@ RememberIndexForRebuilding(Oid indoid, AlteredTableInfo *tab) tab->changedIndexDefs = lappend(tab->changedIndexDefs, defstring); + /* + * Remember if this index is used for the table's replica identity + * or if it is a clustered index, so that ATPostAlterTypeCleanup() + * can queue up commands necessary to restore those properties. + */ RememberReplicaIdentityForRebuilding(indoid, tab); + RememberClusterOnForRebuilding(indoid, tab); } } } @@ -9739,6 +9770,21 @@ ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab, LOCKMODE lockmode) lappend(tab->subcmds[AT_PASS_OLD_CONSTR], cmd); } + /* + * Queue up command to restore marking of index used for cluster. + */ + if (tab->clusterOnIndex) + { + AlterTableCmd *cmd = makeNode(AlterTableCmd); + + cmd->subtype = AT_ClusterOn; + cmd->name = tab->clusterOnIndex; + + /* do it after indexes and constraints */ + tab->subcmds[AT_PASS_OLD_CONSTR] = + lappend(tab->subcmds[AT_PASS_OLD_CONSTR], cmd); + } + /* * Now we can drop the existing constraints and indexes --- constraints * first, since some of them might depend on the indexes. In fact, we diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c index db62daf77ec..6a6336c8619 100644 --- a/src/backend/utils/cache/lsyscache.c +++ b/src/backend/utils/cache/lsyscache.c @@ -3163,3 +3163,26 @@ get_index_isreplident(Oid index_oid) return result; } + +/* + * get_index_isclustered + * + * Given the index OID, return pg_index.indisclustered. + */ +bool +get_index_isclustered(Oid index_oid) +{ + bool isclustered; + HeapTuple tuple; + Form_pg_index rd_index; + + tuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(index_oid)); + if (!HeapTupleIsValid(tuple)) + elog(ERROR, "cache lookup failed for index %u", index_oid); + + rd_index = (Form_pg_index) GETSTRUCT(tuple); + isclustered = rd_index->indisclustered; + ReleaseSysCache(tuple); + + return isclustered; +} diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h index 770972a2818..3e545bdbb22 100644 --- a/src/include/utils/lsyscache.h +++ b/src/include/utils/lsyscache.h @@ -179,6 +179,7 @@ extern char *get_namespace_name_or_temp(Oid nspid); extern Oid get_range_subtype(Oid rangeOid); extern Oid get_range_collation(Oid rangeOid); extern bool get_index_isreplident(Oid index_oid); +extern bool get_index_isclustered(Oid index_oid); #define type_is_array(typid) (get_element_type(typid) != InvalidOid) /* type_is_array_domain accepts both plain arrays and domains over arrays */ diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out index dc6c07f3a5e..eabd3e160cd 100644 --- a/src/test/regress/expected/alter_table.out +++ b/src/test/regress/expected/alter_table.out @@ -3788,3 +3788,51 @@ alter table at_test_sql_partop attach partition at_test_sql_partop_1 for values drop table at_test_sql_partop; drop operator class at_test_sql_partop using btree; drop function at_test_sql_partop; +-- Test that ALTER TABLE rewrite preserves a clustered index +-- for normal indexes and indexes on constraints. +create table alttype_cluster (a int); +alter table alttype_cluster add primary key (a); +create index alttype_cluster_ind on alttype_cluster (a); +alter table alttype_cluster cluster on alttype_cluster_ind; +-- Normal index remains clustered. +select indexrelid::regclass, indisclustered from pg_index + where indrelid = 'alttype_cluster'::regclass + order by indexrelid::regclass::text; + indexrelid | indisclustered +----------------------+---------------- + alttype_cluster_ind | t + alttype_cluster_pkey | f +(2 rows) + +alter table alttype_cluster alter a type bigint; +select indexrelid::regclass, indisclustered from pg_index + where indrelid = 'alttype_cluster'::regclass + order by indexrelid::regclass::text; + indexrelid | indisclustered +----------------------+---------------- + alttype_cluster_ind | t + alttype_cluster_pkey | f +(2 rows) + +-- Constraint index remains clustered. +alter table alttype_cluster cluster on alttype_cluster_pkey; +select indexrelid::regclass, indisclustered from pg_index + where indrelid = 'alttype_cluster'::regclass + order by indexrelid::regclass::text; + indexrelid | indisclustered +----------------------+---------------- + alttype_cluster_ind | f + alttype_cluster_pkey | t +(2 rows) + +alter table alttype_cluster alter a type int; +select indexrelid::regclass, indisclustered from pg_index + where indrelid = 'alttype_cluster'::regclass + order by indexrelid::regclass::text; + indexrelid | indisclustered +----------------------+---------------- + alttype_cluster_ind | f + alttype_cluster_pkey | t +(2 rows) + +drop table alttype_cluster; diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql index 7193bf948ce..8afdf0613e8 100644 --- a/src/test/regress/sql/alter_table.sql +++ b/src/test/regress/sql/alter_table.sql @@ -2463,3 +2463,28 @@ alter table at_test_sql_partop attach partition at_test_sql_partop_1 for values drop table at_test_sql_partop; drop operator class at_test_sql_partop using btree; drop function at_test_sql_partop; + +-- Test that ALTER TABLE rewrite preserves a clustered index +-- for normal indexes and indexes on constraints. +create table alttype_cluster (a int); +alter table alttype_cluster add primary key (a); +create index alttype_cluster_ind on alttype_cluster (a); +alter table alttype_cluster cluster on alttype_cluster_ind; +-- Normal index remains clustered. +select indexrelid::regclass, indisclustered from pg_index + where indrelid = 'alttype_cluster'::regclass + order by indexrelid::regclass::text; +alter table alttype_cluster alter a type bigint; +select indexrelid::regclass, indisclustered from pg_index + where indrelid = 'alttype_cluster'::regclass + order by indexrelid::regclass::text; +-- Constraint index remains clustered. +alter table alttype_cluster cluster on alttype_cluster_pkey; +select indexrelid::regclass, indisclustered from pg_index + where indrelid = 'alttype_cluster'::regclass + order by indexrelid::regclass::text; +alter table alttype_cluster alter a type int; +select indexrelid::regclass, indisclustered from pg_index + where indrelid = 'alttype_cluster'::regclass + order by indexrelid::regclass::text; +drop table alttype_cluster;