On 2020-02-11 00:38, Quan Zongliang wrote:
new patch attached.
I didn't like so much how the updating of the replica identity was
hacked into the middle of ATRewriteCatalogs(). I have an alternative
proposal in the attached patch that queues up an ALTER TABLE ... REPLICA
IDENTITY command into the normal ALTER TABLE processing. I have also
added tests to the test suite.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
From 730a5dc46ec9722aa0416e5a85987c6385e6170c Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <pe...@eisentraut.org>
Date: Thu, 5 Mar 2020 10:11:13 +0100
Subject: [PATCH v4] Preserve replica identity index across ALTER TABLE rewrite
---
src/backend/commands/tablecmds.c | 42 +++++++++++++++++
src/backend/utils/cache/lsyscache.c | 23 ++++++++++
src/include/utils/lsyscache.h | 1 +
.../regress/expected/replica_identity.out | 46 +++++++++++++++++++
src/test/regress/sql/replica_identity.sql | 21 +++++++++
5 files changed, 133 insertions(+)
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 7a13b97164..8edec9cbe7 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -176,6 +176,7 @@ typedef struct AlteredTableInfo
List *changedConstraintDefs; /* string definitions of same */
List *changedIndexOids; /* OIDs of indexes to rebuild */
List *changedIndexDefs; /* string definitions of same */
+ char *replicaIdentityIndex; /* index to reset as REPLICA
IDENTITY */
} AlteredTableInfo;
/* Struct describing one new constraint to check in Phase 3 scan */
@@ -11564,6 +11565,22 @@ ATExecAlterColumnType(AlteredTableInfo *tab, Relation
rel,
return address;
}
+/*
+ * Subroutine for ATExecAlterColumnType: remember that a replica identity
+ * needs to be reset.
+ */
+static void
+RememberReplicaIdentityForRebuilding(Oid indoid, AlteredTableInfo *tab)
+{
+ if (!get_index_is_replident(indoid))
+ return;
+
+ if (tab->replicaIdentityIndex)
+ elog(ERROR, "relation %u has multiple indexes marked as replica
identity", tab->relid);
+
+ tab->replicaIdentityIndex = get_rel_name(indoid);
+}
+
/*
* Subroutine for ATExecAlterColumnType: remember that a constraint needs
* to be rebuilt (which we might already know).
@@ -11582,11 +11599,16 @@ RememberConstraintForRebuilding(Oid conoid,
AlteredTableInfo *tab)
{
/* OK, capture the constraint's existing definition string */
char *defstring = pg_get_constraintdef_command(conoid);
+ Oid indoid;
tab->changedConstraintOids =
lappend_oid(tab->changedConstraintOids,
conoid);
tab->changedConstraintDefs = lappend(tab->changedConstraintDefs,
defstring);
+
+ indoid = get_constraint_index(conoid);
+ if (OidIsValid(indoid))
+ RememberReplicaIdentityForRebuilding(indoid, tab);
}
}
@@ -11629,6 +11651,8 @@ RememberIndexForRebuilding(Oid indoid, AlteredTableInfo
*tab)
indoid);
tab->changedIndexDefs = lappend(tab->changedIndexDefs,
defstring);
+
+ RememberReplicaIdentityForRebuilding(indoid, tab);
}
}
}
@@ -11737,6 +11761,24 @@ ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo
*tab, LOCKMODE lockmode)
add_exact_object_address(&obj, objects);
}
+ /*
+ * Queue up command to restore replica identity index marking
+ */
+ if (tab->replicaIdentityIndex)
+ {
+ AlterTableCmd *cmd = makeNode(AlterTableCmd);
+ ReplicaIdentityStmt *subcmd = makeNode(ReplicaIdentityStmt);
+
+ subcmd->identity_type = REPLICA_IDENTITY_INDEX;
+ subcmd->name = tab->replicaIdentityIndex;
+ cmd->subtype = AT_ReplicaIdentity;
+ cmd->def = (Node *) subcmd;
+
+ /* do it after indexes and constraints */
+ tab->subcmds[AT_PASS_OLD_CONSTR] =
+ lappend(tab->subcmds[AT_PASS_OLD_CONSTR], cmd);
+ }
+
/*
* It should be okay to use DROP_RESTRICT here, since nothing else
should
* be depending on these objects.
diff --git a/src/backend/utils/cache/lsyscache.c
b/src/backend/utils/cache/lsyscache.c
index 3da90cb72a..f7b0c1408f 100644
--- a/src/backend/utils/cache/lsyscache.c
+++ b/src/backend/utils/cache/lsyscache.c
@@ -3227,3 +3227,26 @@ get_index_column_opclass(Oid index_oid, int attno)
return opclass;
}
+
+/*
+ * get_index_is_replident
+ *
+ * Returns indisreplident field.
+ */
+bool
+get_index_is_replident(Oid index_oid)
+{
+ HeapTuple tuple;
+ Form_pg_index rd_index;
+ bool result;
+
+ tuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(index_oid));
+ if (!HeapTupleIsValid(tuple))
+ return false;
+
+ rd_index = (Form_pg_index) GETSTRUCT(tuple);
+ result = rd_index->indisreplident;
+ ReleaseSysCache(tuple);
+
+ return result;
+}
diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h
index f132d39458..ee4683843e 100644
--- a/src/include/utils/lsyscache.h
+++ b/src/include/utils/lsyscache.h
@@ -181,6 +181,7 @@ extern char *get_namespace_name_or_temp(Oid nspid);
extern Oid get_range_subtype(Oid rangeOid);
extern Oid get_range_collation(Oid rangeOid);
extern Oid get_index_column_opclass(Oid index_oid, int attno);
+extern bool get_index_is_replident(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/replica_identity.out
b/src/test/regress/expected/replica_identity.out
index 739608aab4..79002197a7 100644
--- a/src/test/regress/expected/replica_identity.out
+++ b/src/test/regress/expected/replica_identity.out
@@ -179,5 +179,51 @@ SELECT relreplident FROM pg_class WHERE oid =
'test_replica_identity'::regclass;
n
(1 row)
+---
+-- Test that ALTER TABLE rewrite preserves nondefault replica identity
+---
+-- constraint variant
+CREATE TABLE test_replica_identity2 (id int UNIQUE NOT NULL);
+ALTER TABLE test_replica_identity2 REPLICA IDENTITY USING INDEX
test_replica_identity2_id_key;
+\d test_replica_identity2
+ Table "public.test_replica_identity2"
+ Column | Type | Collation | Nullable | Default
+--------+---------+-----------+----------+---------
+ id | integer | | not null |
+Indexes:
+ "test_replica_identity2_id_key" UNIQUE CONSTRAINT, btree (id) REPLICA
IDENTITY
+
+ALTER TABLE test_replica_identity2 ALTER COLUMN id TYPE bigint;
+\d test_replica_identity2
+ Table "public.test_replica_identity2"
+ Column | Type | Collation | Nullable | Default
+--------+--------+-----------+----------+---------
+ id | bigint | | not null |
+Indexes:
+ "test_replica_identity2_id_key" UNIQUE CONSTRAINT, btree (id) REPLICA
IDENTITY
+
+-- straight index variant
+CREATE TABLE test_replica_identity3 (id int NOT NULL);
+CREATE UNIQUE INDEX test_replica_identity3_id_key ON test_replica_identity3
(id);
+ALTER TABLE test_replica_identity3 REPLICA IDENTITY USING INDEX
test_replica_identity3_id_key;
+\d test_replica_identity3
+ Table "public.test_replica_identity3"
+ Column | Type | Collation | Nullable | Default
+--------+---------+-----------+----------+---------
+ id | integer | | not null |
+Indexes:
+ "test_replica_identity3_id_key" UNIQUE, btree (id) REPLICA IDENTITY
+
+ALTER TABLE test_replica_identity3 ALTER COLUMN id TYPE bigint;
+\d test_replica_identity3
+ Table "public.test_replica_identity3"
+ Column | Type | Collation | Nullable | Default
+--------+--------+-----------+----------+---------
+ id | bigint | | not null |
+Indexes:
+ "test_replica_identity3_id_key" UNIQUE, btree (id) REPLICA IDENTITY
+
DROP TABLE test_replica_identity;
+DROP TABLE test_replica_identity2;
+DROP TABLE test_replica_identity3;
DROP TABLE test_replica_identity_othertable;
diff --git a/src/test/regress/sql/replica_identity.sql
b/src/test/regress/sql/replica_identity.sql
index b08a3623b8..a5ac8f5567 100644
--- a/src/test/regress/sql/replica_identity.sql
+++ b/src/test/regress/sql/replica_identity.sql
@@ -75,5 +75,26 @@ CREATE UNIQUE INDEX test_replica_identity_partial ON
test_replica_identity (keya
ALTER TABLE test_replica_identity REPLICA IDENTITY NOTHING;
SELECT relreplident FROM pg_class WHERE oid =
'test_replica_identity'::regclass;
+---
+-- Test that ALTER TABLE rewrite preserves nondefault replica identity
+---
+
+-- constraint variant
+CREATE TABLE test_replica_identity2 (id int UNIQUE NOT NULL);
+ALTER TABLE test_replica_identity2 REPLICA IDENTITY USING INDEX
test_replica_identity2_id_key;
+\d test_replica_identity2
+ALTER TABLE test_replica_identity2 ALTER COLUMN id TYPE bigint;
+\d test_replica_identity2
+
+-- straight index variant
+CREATE TABLE test_replica_identity3 (id int NOT NULL);
+CREATE UNIQUE INDEX test_replica_identity3_id_key ON test_replica_identity3
(id);
+ALTER TABLE test_replica_identity3 REPLICA IDENTITY USING INDEX
test_replica_identity3_id_key;
+\d test_replica_identity3
+ALTER TABLE test_replica_identity3 ALTER COLUMN id TYPE bigint;
+\d test_replica_identity3
+
DROP TABLE test_replica_identity;
+DROP TABLE test_replica_identity2;
+DROP TABLE test_replica_identity3;
DROP TABLE test_replica_identity_othertable;
--
2.25.0
