From 817c469c2a167518a7cb44a84c996c7d11a728e4 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Thu, 25 Nov 2021 15:05:37 +0900
Subject: [PATCH] Block ALTER TABLE .. DROP NOT NULL on columns in replica
identity index
Replica identities that depend directly on an index rely on a set of
properties, one of them being that all the columns defined in this index
have to be marked as NOT NULL. There was a hole in the logic with ALTER
TABLE DROP NOT NULL, where it was possible to remove the NOT NULL
property of a column part of an index used as replica identity, so block
it to avoid problems with logical decoding down the road.
The same check was already done columns part of a primary key, so the
fix is straight-forward.
Author: Haiying Tang, Hou Zhijie
Reviewed-by: Dilip Kumar, Michael Paquier
Discussion: https://postgr.es/m/OS0PR01MB6113338C102BEE8B2FFC5BD9FB619@OS0PR01MB6113.jpnprd01.prod.outlook.com
Backpatch-through: 10
---
src/backend/commands/tablecmds.c | 31 +++++++++++++------
.../regress/expected/replica_identity.out | 4 +++
src/test/regress/sql/replica_identity.sql | 4 +++
3 files changed, 30 insertions(+), 9 deletions(-)
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index c35bf678217..ef88a10f017 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -5707,7 +5707,8 @@ ATExecDropNotNull(Relation rel, const char *colName, LOCKMODE lockmode)
colName, RelationGetRelationName(rel))));
/*
- * Check that the attribute is not in a primary key
+ * Check that the attribute is not in a primary key or in an index used as
+ * a replica identity.
*
* Note: we'll throw error even if the pkey index is not valid.
*/
@@ -5727,20 +5728,32 @@ ATExecDropNotNull(Relation rel, const char *colName, LOCKMODE lockmode)
elog(ERROR, "cache lookup failed for index %u", indexoid);
indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
- /* If the index is not a primary key, skip the check */
- if (indexStruct->indisprimary)
+ /*
+ * If the index is not a primary key or an index used as replica
+ * identity, skip the check.
+ */
+ if (indexStruct->indisprimary || indexStruct->indisreplident)
{
/*
- * Loop over each attribute in the primary key and see if it
- * matches the to-be-altered attribute
+ * Loop over each attribute in the primary key or the index used
+ * as replica identity and see if it matches the to-be-altered
+ * attribute.
*/
for (i = 0; i < indexStruct->indnatts; i++)
{
if (indexStruct->indkey.values[i] == attnum)
- ereport(ERROR,
- (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
- errmsg("column \"%s\" is in a primary key",
- colName)));
+ {
+ if (indexStruct->indisprimary)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+ errmsg("column \"%s\" is in a primary key",
+ colName)));
+ else
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+ errmsg("column \"%s\" is in index used as replica identity",
+ colName)));
+ }
}
}
diff --git a/src/test/regress/expected/replica_identity.out b/src/test/regress/expected/replica_identity.out
index 65c7c9ac9f8..3fc1943f2c4 100644
--- a/src/test/regress/expected/replica_identity.out
+++ b/src/test/regress/expected/replica_identity.out
@@ -230,6 +230,10 @@ ALTER TABLE test_replica_identity3 ALTER COLUMN id TYPE bigint;
Indexes:
"test_replica_identity3_id_key" UNIQUE, btree (id) REPLICA IDENTITY
+-- ALTER TABLE DROP NOT NULL is not allowed for columns part of an index
+-- used as replica identity.
+ALTER TABLE test_replica_identity3 ALTER COLUMN id DROP NOT NULL;
+ERROR: column "id" is in index used as replica identity
DROP TABLE test_replica_identity;
DROP TABLE test_replica_identity2;
DROP TABLE test_replica_identity3;
diff --git a/src/test/regress/sql/replica_identity.sql b/src/test/regress/sql/replica_identity.sql
index 5277ff39cd3..f2c848b9800 100644
--- a/src/test/regress/sql/replica_identity.sql
+++ b/src/test/regress/sql/replica_identity.sql
@@ -98,6 +98,10 @@ ALTER TABLE test_replica_identity3 REPLICA IDENTITY USING INDEX test_replica_ide
ALTER TABLE test_replica_identity3 ALTER COLUMN id TYPE bigint;
\d test_replica_identity3
+-- ALTER TABLE DROP NOT NULL is not allowed for columns part of an index
+-- used as replica identity.
+ALTER TABLE test_replica_identity3 ALTER COLUMN id DROP NOT NULL;
+
DROP TABLE test_replica_identity;
DROP TABLE test_replica_identity2;
DROP TABLE test_replica_identity3;
--
2.39.5