Checks for ALTER TABLE ... SPLIT/MERGE PARTITIONS ... commands

Check that the target partition actually belongs to the parent table.

Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/cd842601-cf1a-9806-f7b7-d2509b93ba61%40gmail.com
Author: Dmitry Koval

src/backend/commands/tablecmds.c

@@ -21223,12 +21223,6 @@ ATExecSplitPartition(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	 */
 	splitRel = table_openrv(cmd->name, AccessExclusiveLock);
 
-	if (splitRel->rd_rel->relkind != RELKIND_RELATION)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("cannot split non-table partition \"%s\"",
-						RelationGetRelationName(splitRel))));
-
 	splitRelOid = RelationGetRelid(splitRel);
 
 	/* Check descriptions of new partitions. */
@@ -21463,12 +21457,6 @@ ATExecMergePartitions(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		 */
 		mergingPartition = table_openrv(name, AccessExclusiveLock);
 
-		if (mergingPartition->rd_rel->relkind != RELKIND_RELATION)
-			ereport(ERROR,
-					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-					 errmsg("cannot merge non-table partition \"%s\"",
-							RelationGetRelationName(mergingPartition))));
-
 		/*
 		 * Checking that two partitions have the same name was before, in
 		 * function transformPartitionCmdForMerge().

src/backend/parser/parse_utilcmd.c

@@ -32,6 +32,7 @@
 #include "catalog/heap.h"
 #include "catalog/index.h"
 #include "catalog/namespace.h"
+#include "catalog/partition.h"
 #include "catalog/pg_am.h"
 #include "catalog/pg_collation.h"
 #include "catalog/pg_constraint.h"
@@ -3415,6 +3416,39 @@ transformRuleStmt(RuleStmt *stmt, const char *queryString,
 }
 
 
+/*
+ * checkPartition
+ *		Check that partRelOid is an oid of partition of the parent table rel
+ */
+static void
+checkPartition(Relation rel, Oid partRelOid)
+{
+	Relation	partRel;
+
+	partRel = relation_open(partRelOid, AccessShareLock);
+
+	if (partRel->rd_rel->relkind != RELKIND_RELATION)
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("\"%s\" is not a table",
+						RelationGetRelationName(partRel))));
+
+	if (!partRel->rd_rel->relispartition)
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("\"%s\" is not a partition",
+						RelationGetRelationName(partRel))));
+
+	if (get_partition_parent(partRelOid, false) != RelationGetRelid(rel))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_TABLE),
+				 errmsg("relation \"%s\" is not a partition of relation \"%s\"",
+						RelationGetRelationName(partRel),
+						RelationGetRelationName(rel))));
+
+	relation_close(partRel, AccessShareLock);
+}
+
 /*
  * transformPartitionCmdForSplit
  *		Analyze the ALTER TABLLE ... SPLIT PARTITION command
@@ -3447,6 +3481,8 @@ transformPartitionCmdForSplit(CreateStmtContext *cxt, PartitionCmd *partcmd)
 
 	splitPartOid = RangeVarGetRelid(partcmd->name, NoLock, false);
 
+	checkPartition(parent, splitPartOid);
+
 	/* Then we should check partitions with transformed bounds. */
 	check_partitions_for_split(parent, splitPartOid, partcmd->name, partcmd->partlist, cxt->pstate);
 }
@@ -3509,6 +3545,9 @@ transformPartitionCmdForMerge(CreateStmtContext *cxt, PartitionCmd *partcmd)
 		partOid = RangeVarGetRelid(name, NoLock, false);
 		if (partOid == defaultPartOid)
 			isDefaultPart = true;
+
+		checkPartition(parent, partOid);
+
 		partOids = lappend_oid(partOids, partOid);
 	}
 

src/test/regress/expected/partition_merge.out

@@ -25,9 +25,9 @@ ALTER TABLE sales_range MERGE PARTITIONS (sales_feb2022, sales_mar2022, sales_fe
 ERROR:  partition with name "sales_feb2022" already used
 LINE 1: ...e MERGE PARTITIONS (sales_feb2022, sales_mar2022, sales_feb2...
                                                              ^
--- ERROR:  cannot merge non-table partition "sales_apr2022"
+-- ERROR:  "sales_apr2022" is not a table
 ALTER TABLE sales_range MERGE PARTITIONS (sales_feb2022, sales_mar2022, sales_apr2022) INTO sales_feb_mar_apr2022;
-ERROR:  cannot merge non-table partition "sales_apr2022"
+ERROR:  "sales_apr2022" is not a table
 -- ERROR:  invalid partitions order, partition "sales_mar2022" can not be merged
 -- (space between sections sales_jan2022 and sales_mar2022)
 ALTER TABLE sales_range MERGE PARTITIONS (sales_jan2022, sales_mar2022) INTO sales_jan_mar2022;
@@ -590,12 +590,12 @@ CREATE TABLE sales_nord2 PARTITION OF sales_list2 FOR VALUES IN ('Oslo', 'St. Pe
 CREATE TABLE sales_others2 PARTITION OF sales_list2 DEFAULT;
 CREATE TABLE sales_external (LIKE sales_list);
 CREATE TABLE sales_external2 (vch VARCHAR(5));
--- ERROR:  partition bound for relation "sales_external" is null
+-- ERROR:  "sales_external" is not a partition
 ALTER TABLE sales_list MERGE PARTITIONS (sales_west, sales_east, sales_external) INTO sales_all;
-ERROR:  partition bound for relation "sales_external" is null
+ERROR:  "sales_external" is not a partition
--- ERROR:  partition bound for relation "sales_external2" is null
+-- ERROR:  "sales_external2" is not a partition
 ALTER TABLE sales_list MERGE PARTITIONS (sales_west, sales_east, sales_external2) INTO sales_all;
-ERROR:  partition bound for relation "sales_external2" is null
+ERROR:  "sales_external2" is not a partition
 -- ERROR:  relation "sales_nord2" is not a partition of relation "sales_list"
 ALTER TABLE sales_list MERGE PARTITIONS (sales_west, sales_nord2, sales_east) INTO sales_all;
 ERROR:  relation "sales_nord2" is not a partition of relation "sales_list"
@@ -729,4 +729,21 @@ SELECT * FROM sales_list WHERE salesman_name = 'Ivanov';
 RESET enable_seqscan;
 DROP TABLE sales_list;
 --
+-- Try to MERGE partitions of another table.
+--
+CREATE TABLE t1 (i int, a int, b int, c int) PARTITION BY RANGE (a, b);
+CREATE TABLE t1p1 PARTITION OF t1 FOR VALUES FROM (1, 1) TO (1, 2);
+CREATE TABLE t2 (i int, t text) PARTITION BY RANGE (t);
+CREATE TABLE t2pa PARTITION OF t2 FOR VALUES FROM ('A') TO ('C');
+CREATE TABLE t3 (i int, t text);
+-- ERROR:  relation "t1p1" is not a partition of relation "t2"
+ALTER TABLE t2 MERGE PARTITIONS (t1p1, t2pa) INTO t2p;
+ERROR:  relation "t1p1" is not a partition of relation "t2"
+-- ERROR:  "t3" is not a partition
+ALTER TABLE t2 MERGE PARTITIONS (t2pa, t3) INTO t2p;
+ERROR:  "t3" is not a partition
+DROP TABLE t3;
+DROP TABLE t2;
+DROP TABLE t1;
+--
 DROP SCHEMA partitions_merge_schema;

src/test/regress/expected/partition_split.out

@@ -1414,4 +1414,17 @@ SELECT * FROM sales_others;
 
 DROP TABLE sales_range;
 --
+-- Try to SPLIT partition of another table.
+--
+CREATE TABLE t1(i int, t text) PARTITION BY LIST (t);
+CREATE TABLE t1pa PARTITION OF t1 FOR VALUES IN ('A');
+CREATE TABLE t2 (i int, t text) PARTITION BY RANGE (t);
+-- ERROR:  relation "t1pa" is not a partition of relation "t2"
+ALTER TABLE t2 SPLIT PARTITION t1pa INTO
+   (PARTITION t2a FOR VALUES FROM ('A') TO ('B'),
+    PARTITION t2b FOR VALUES FROM ('B') TO ('C'));
+ERROR:  relation "t1pa" is not a partition of relation "t2"
+DROP TABLE t2;
+DROP TABLE t1;
+--
 DROP SCHEMA partition_split_schema;

src/test/regress/sql/partition_merge.sql

@@ -28,7 +28,7 @@ CREATE TABLE sales_others PARTITION OF sales_range DEFAULT;
 
 -- ERROR:  partition with name "sales_feb2022" already used
 ALTER TABLE sales_range MERGE PARTITIONS (sales_feb2022, sales_mar2022, sales_feb2022) INTO sales_feb_mar_apr2022;
--- ERROR:  cannot merge non-table partition "sales_apr2022"
+-- ERROR:  "sales_apr2022" is not a table
 ALTER TABLE sales_range MERGE PARTITIONS (sales_feb2022, sales_mar2022, sales_apr2022) INTO sales_feb_mar_apr2022;
 -- ERROR:  invalid partitions order, partition "sales_mar2022" can not be merged
 -- (space between sections sales_jan2022 and sales_mar2022)
@@ -350,9 +350,9 @@ CREATE TABLE sales_others2 PARTITION OF sales_list2 DEFAULT;
 CREATE TABLE sales_external (LIKE sales_list);
 CREATE TABLE sales_external2 (vch VARCHAR(5));
 
--- ERROR:  partition bound for relation "sales_external" is null
+-- ERROR:  "sales_external" is not a partition
 ALTER TABLE sales_list MERGE PARTITIONS (sales_west, sales_east, sales_external) INTO sales_all;
--- ERROR:  partition bound for relation "sales_external2" is null
+-- ERROR:  "sales_external2" is not a partition
 ALTER TABLE sales_list MERGE PARTITIONS (sales_west, sales_east, sales_external2) INTO sales_all;
 -- ERROR:  relation "sales_nord2" is not a partition of relation "sales_list"
 ALTER TABLE sales_list MERGE PARTITIONS (sales_west, sales_nord2, sales_east) INTO sales_all;
@@ -426,5 +426,23 @@ RESET enable_seqscan;
 
 DROP TABLE sales_list;
 
+--
+-- Try to MERGE partitions of another table.
+--
+CREATE TABLE t1 (i int, a int, b int, c int) PARTITION BY RANGE (a, b);
+CREATE TABLE t1p1 PARTITION OF t1 FOR VALUES FROM (1, 1) TO (1, 2);
+CREATE TABLE t2 (i int, t text) PARTITION BY RANGE (t);
+CREATE TABLE t2pa PARTITION OF t2 FOR VALUES FROM ('A') TO ('C');
+CREATE TABLE t3 (i int, t text);
+
+-- ERROR:  relation "t1p1" is not a partition of relation "t2"
+ALTER TABLE t2 MERGE PARTITIONS (t1p1, t2pa) INTO t2p;
+-- ERROR:  "t3" is not a partition
+ALTER TABLE t2 MERGE PARTITIONS (t2pa, t3) INTO t2p;
+
+DROP TABLE t3;
+DROP TABLE t2;
+DROP TABLE t1;
+
 --
 DROP SCHEMA partitions_merge_schema;

src/test/regress/sql/partition_split.sql

@@ -829,5 +829,20 @@ SELECT * FROM sales_others;
 
 DROP TABLE sales_range;
 
+--
+-- Try to SPLIT partition of another table.
+--
+CREATE TABLE t1(i int, t text) PARTITION BY LIST (t);
+CREATE TABLE t1pa PARTITION OF t1 FOR VALUES IN ('A');
+CREATE TABLE t2 (i int, t text) PARTITION BY RANGE (t);
+
+-- ERROR:  relation "t1pa" is not a partition of relation "t2"
+ALTER TABLE t2 SPLIT PARTITION t1pa INTO
+   (PARTITION t2a FOR VALUES FROM ('A') TO ('B'),
+    PARTITION t2b FOR VALUES FROM ('B') TO ('C'));
+
+DROP TABLE t2;
+DROP TABLE t1;
+
 --
 DROP SCHEMA partition_split_schema;