Foreign keys on partitioned tables

Author: Álvaro Herrera
Discussion: https://postgr.es/m/20171231194359.cvojcour423ulha4@alvherre.pgsql
Reviewed-by: Peter Eisentraut

doc/src/sgml/ref/alter_table.sgml

@@ -368,7 +368,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       specified check constraints).  But the
       database will not assume that the constraint holds for all rows in
       the table, until it is validated by using the <literal>VALIDATE
-      CONSTRAINT</literal> option.
+      CONSTRAINT</literal> option.  Foreign key constraints on partitioned
+      tables may not be declared <literal>NOT VALID</literal> at present.
      </para>
 
      <para>

doc/src/sgml/ref/create_table.sgml

@@ -546,9 +546,12 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
      </para>
 
      <para>
-      Partitioned tables do not support <literal>EXCLUDE</literal> or
-      <literal>FOREIGN KEY</literal> constraints; however, you can define
-      these constraints on individual partitions.
+      Partitioned tables do not support <literal>EXCLUDE</literal> constraints;
+      however, you can define these constraints on individual partitions.
+      Also, while it's possible to define <literal>PRIMARY KEY</literal>
+      constraints on partitioned tables, it is not supported to create foreign
+      keys cannot that reference them.  This restriction will be lifted in a
+      future release.
      </para>
 
     </listitem>
@@ -907,7 +910,9 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       must have <literal>REFERENCES</literal> permission on the referenced table
       (either the whole table, or the specific referenced columns).
       Note that foreign key constraints cannot be defined between temporary
-      tables and permanent tables.
+      tables and permanent tables.  Also note that while it is possible to
+      define a foreign key on a partitioned table, it is not possible to
+      declare a foreign key that references a partitioned table.
      </para>
 
      <para>

src/backend/catalog/pg_constraint.c

@@ -26,6 +26,7 @@
 #include "catalog/pg_operator.h"
 #include "catalog/pg_type.h"
 #include "commands/defrem.h"
+#include "commands/tablecmds.h"
 #include "utils/array.h"
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
@@ -377,6 +378,242 @@ CreateConstraintEntry(const char *constraintName,
 	return conOid;
 }
 
+/*
+ * CloneForeignKeyConstraints
+ *		Clone foreign keys from a partitioned table to a newly acquired
+ *		partition.
+ *
+ * relationId is a partition of parentId, so we can be certain that it has the
+ * same columns with the same datatypes.  The columns may be in different
+ * order, though.
+ *
+ * The *cloned list is appended ClonedConstraint elements describing what was
+ * created.
+ */
+void
+CloneForeignKeyConstraints(Oid parentId, Oid relationId, List **cloned)
+{
+	Relation	pg_constraint;
+	Relation	parentRel;
+	Relation	rel;
+	ScanKeyData	key;
+	SysScanDesc	scan;
+	TupleDesc	tupdesc;
+	HeapTuple	tuple;
+	AttrNumber *attmap;
+
+	parentRel = heap_open(parentId, NoLock);	/* already got lock */
+	/* see ATAddForeignKeyConstraint about lock level */
+	rel = heap_open(relationId, AccessExclusiveLock);
+
+	pg_constraint = heap_open(ConstraintRelationId, RowShareLock);
+	tupdesc = RelationGetDescr(pg_constraint);
+
+	/*
+	 * The constraint key may differ, if the columns in the partition are
+	 * different.  This map is used to convert them.
+	 */
+	attmap = convert_tuples_by_name_map(RelationGetDescr(rel),
+										RelationGetDescr(parentRel),
+										gettext_noop("could not convert row type"));
+
+	ScanKeyInit(&key,
+				Anum_pg_constraint_conrelid, BTEqualStrategyNumber,
+				F_OIDEQ, ObjectIdGetDatum(parentId));
+	scan = systable_beginscan(pg_constraint, ConstraintRelidIndexId, true,
+							  NULL, 1, &key);
+
+	while ((tuple = systable_getnext(scan)) != NULL)
+	{
+		Form_pg_constraint	constrForm = (Form_pg_constraint) GETSTRUCT(tuple);
+		AttrNumber	conkey[INDEX_MAX_KEYS];
+		AttrNumber	mapped_conkey[INDEX_MAX_KEYS];
+		AttrNumber	confkey[INDEX_MAX_KEYS];
+		Oid			conpfeqop[INDEX_MAX_KEYS];
+		Oid			conppeqop[INDEX_MAX_KEYS];
+		Oid			conffeqop[INDEX_MAX_KEYS];
+		Constraint *fkconstraint;
+		ClonedConstraint *newc;
+		Oid			constrOid;
+		ObjectAddress parentAddr,
+					childAddr;
+		int			nelem;
+		int			i;
+		ArrayType  *arr;
+		Datum		datum;
+		bool		isnull;
+
+		/* only foreign keys */
+		if (constrForm->contype != CONSTRAINT_FOREIGN)
+			continue;
+
+		ObjectAddressSet(parentAddr, ConstraintRelationId,
+						 HeapTupleGetOid(tuple));
+
+		datum = fastgetattr(tuple, Anum_pg_constraint_conkey,
+							tupdesc, &isnull);
+		if (isnull)
+			elog(ERROR, "null conkey");
+		arr = DatumGetArrayTypeP(datum);
+		nelem = ARR_DIMS(arr)[0];
+		if (ARR_NDIM(arr) != 1 ||
+			nelem < 1 ||
+			nelem > INDEX_MAX_KEYS ||
+			ARR_HASNULL(arr) ||
+			ARR_ELEMTYPE(arr) != INT2OID)
+			elog(ERROR, "conkey is not a 1-D smallint array");
+		memcpy(conkey, ARR_DATA_PTR(arr), nelem * sizeof(AttrNumber));
+
+		for (i = 0; i < nelem; i++)
+			mapped_conkey[i] = attmap[conkey[i] - 1];
+
+		datum = fastgetattr(tuple, Anum_pg_constraint_confkey,
+							tupdesc, &isnull);
+		if (isnull)
+			elog(ERROR, "null confkey");
+		arr = DatumGetArrayTypeP(datum);
+		nelem = ARR_DIMS(arr)[0];
+		if (ARR_NDIM(arr) != 1 ||
+			nelem < 1 ||
+			nelem > INDEX_MAX_KEYS ||
+			ARR_HASNULL(arr) ||
+			ARR_ELEMTYPE(arr) != INT2OID)
+			elog(ERROR, "confkey is not a 1-D smallint array");
+		memcpy(confkey, ARR_DATA_PTR(arr), nelem * sizeof(AttrNumber));
+
+		datum = fastgetattr(tuple, Anum_pg_constraint_conpfeqop,
+							tupdesc, &isnull);
+		if (isnull)
+			elog(ERROR, "null conpfeqop");
+		arr = DatumGetArrayTypeP(datum);
+		nelem = ARR_DIMS(arr)[0];
+		if (ARR_NDIM(arr) != 1 ||
+			nelem < 1 ||
+			nelem > INDEX_MAX_KEYS ||
+			ARR_HASNULL(arr) ||
+			ARR_ELEMTYPE(arr) != OIDOID)
+			elog(ERROR, "conpfeqop is not a 1-D OID array");
+		memcpy(conpfeqop, ARR_DATA_PTR(arr), nelem * sizeof(Oid));
+
+		datum = fastgetattr(tuple, Anum_pg_constraint_conpfeqop,
+							tupdesc, &isnull);
+		if (isnull)
+			elog(ERROR, "null conpfeqop");
+		arr = DatumGetArrayTypeP(datum);
+		nelem = ARR_DIMS(arr)[0];
+		if (ARR_NDIM(arr) != 1 ||
+			nelem < 1 ||
+			nelem > INDEX_MAX_KEYS ||
+			ARR_HASNULL(arr) ||
+			ARR_ELEMTYPE(arr) != OIDOID)
+			elog(ERROR, "conpfeqop is not a 1-D OID array");
+		memcpy(conpfeqop, ARR_DATA_PTR(arr), nelem * sizeof(Oid));
+
+		datum = fastgetattr(tuple, Anum_pg_constraint_conppeqop,
+							tupdesc, &isnull);
+		if (isnull)
+			elog(ERROR, "null conppeqop");
+		arr = DatumGetArrayTypeP(datum);
+		nelem = ARR_DIMS(arr)[0];
+		if (ARR_NDIM(arr) != 1 ||
+			nelem < 1 ||
+			nelem > INDEX_MAX_KEYS ||
+			ARR_HASNULL(arr) ||
+			ARR_ELEMTYPE(arr) != OIDOID)
+			elog(ERROR, "conppeqop is not a 1-D OID array");
+		memcpy(conppeqop, ARR_DATA_PTR(arr), nelem * sizeof(Oid));
+
+		datum = fastgetattr(tuple, Anum_pg_constraint_conffeqop,
+							tupdesc, &isnull);
+		if (isnull)
+			elog(ERROR, "null conffeqop");
+		arr = DatumGetArrayTypeP(datum);
+		nelem = ARR_DIMS(arr)[0];
+		if (ARR_NDIM(arr) != 1 ||
+			nelem < 1 ||
+			nelem > INDEX_MAX_KEYS ||
+			ARR_HASNULL(arr) ||
+			ARR_ELEMTYPE(arr) != OIDOID)
+			elog(ERROR, "conffeqop is not a 1-D OID array");
+		memcpy(conffeqop, ARR_DATA_PTR(arr), nelem * sizeof(Oid));
+
+		constrOid =
+			CreateConstraintEntry(NameStr(constrForm->conname),
+								  constrForm->connamespace,
+								  CONSTRAINT_FOREIGN,
+								  constrForm->condeferrable,
+								  constrForm->condeferred,
+								  constrForm->convalidated,
+								  HeapTupleGetOid(tuple),
+								  relationId,
+								  mapped_conkey,
+								  nelem,
+								  InvalidOid,	/* not a domain constraint */
+								  constrForm->conindid,	/* same index */
+								  constrForm->confrelid, /* same foreign rel */
+								  confkey,
+								  conpfeqop,
+								  conppeqop,
+								  conffeqop,
+								  nelem,
+								  constrForm->confupdtype,
+								  constrForm->confdeltype,
+								  constrForm->confmatchtype,
+								  NULL,
+								  NULL,
+								  NULL,
+								  NULL,
+								  false,
+								  1, false, true);
+
+		ObjectAddressSet(childAddr, ConstraintRelationId, constrOid);
+		recordDependencyOn(&childAddr, &parentAddr, DEPENDENCY_INTERNAL_AUTO);
+
+		fkconstraint = makeNode(Constraint);
+		/* for now this is all we need */
+		fkconstraint->fk_upd_action = constrForm->confupdtype;
+		fkconstraint->fk_del_action = constrForm->confdeltype;
+		fkconstraint->deferrable = constrForm->condeferrable;
+		fkconstraint->initdeferred = constrForm->condeferred;
+
+		createForeignKeyTriggers(rel, constrForm->confrelid, fkconstraint,
+								 constrOid, constrForm->conindid, false);
+
+		if (cloned)
+		{
+			/*
+			 * Feed back caller about the constraints we created, so that they can
+			 * set up constraint verification.
+			 */
+			newc = palloc(sizeof(ClonedConstraint));
+			newc->relid = relationId;
+			newc->refrelid = constrForm->confrelid;
+			newc->conindid = constrForm->conindid;
+			newc->conid = constrOid;
+			newc->constraint = fkconstraint;
+
+			*cloned = lappend(*cloned, newc);
+		}
+	}
+	systable_endscan(scan);
+
+	pfree(attmap);
+
+	if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
+	{
+		PartitionDesc	partdesc = RelationGetPartitionDesc(rel);
+		int			i;
+
+		for (i = 0; i < partdesc->nparts; i++)
+			CloneForeignKeyConstraints(RelationGetRelid(rel),
+									   partdesc->oids[i],
+									   cloned);
+	}
+
+	heap_close(rel, NoLock);		/* keep lock till commit */
+	heap_close(parentRel, NoLock);
+	heap_close(pg_constraint, RowShareLock);
+}
 
 /*
  * Test whether given name is currently used as a constraint name

src/backend/parser/parse_utilcmd.c

@@ -749,12 +749,6 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 							 errmsg("foreign key constraints are not supported on foreign tables"),
 							 parser_errposition(cxt->pstate,
 												constraint->location)));
-				if (cxt->ispartitioned)
-					ereport(ERROR,
-							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-							 errmsg("foreign key constraints are not supported on partitioned tables"),
-							 parser_errposition(cxt->pstate,
-												constraint->location)));
 
 				/*
 				 * Fill in the current attribute's name and throw it into the
@@ -868,12 +862,6 @@ transformTableConstraint(CreateStmtContext *cxt, Constraint *constraint)
 						 errmsg("foreign key constraints are not supported on foreign tables"),
 						 parser_errposition(cxt->pstate,
 											constraint->location)));
-			if (cxt->ispartitioned)
-				ereport(ERROR,
-						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-						 errmsg("foreign key constraints are not supported on partitioned tables"),
-						 parser_errposition(cxt->pstate,
-											constraint->location)));
 			cxt->fkconstraints = lappend(cxt->fkconstraints, constraint);
 			break;
 

src/backend/utils/adt/ri_triggers.c

@@ -788,20 +788,23 @@ ri_restrict(TriggerData *trigdata, bool is_no_action)
 				char		paramname[16];
 				const char *querysep;
 				Oid			queryoids[RI_MAX_NUMKEYS];
+				const char *fk_only;
 				int			i;
 
 				/* ----------
 				 * The query string built is
-				 *	SELECT 1 FROM ONLY <fktable> x WHERE $1 = fkatt1 [AND ...]
+				 *	SELECT 1 FROM [ONLY] <fktable> x WHERE $1 = fkatt1 [AND ...]
 				 *		   FOR KEY SHARE OF x
 				 * The type id's for the $ parameters are those of the
 				 * corresponding PK attributes.
 				 * ----------
 				 */
 				initStringInfo(&querybuf);
+				fk_only = fk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
+					"" : "ONLY ";
 				quoteRelationName(fkrelname, fk_rel);
-				appendStringInfo(&querybuf, "SELECT 1 FROM ONLY %s x",
-								 fkrelname);
+				appendStringInfo(&querybuf, "SELECT 1 FROM %s%s x",
+								 fk_only, fkrelname);
 				querysep = "WHERE";
 				for (i = 0; i < riinfo->nkeys; i++)
 				{
@@ -947,17 +950,21 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
 				char		paramname[16];
 				const char *querysep;
 				Oid			queryoids[RI_MAX_NUMKEYS];
+				const char *fk_only;
 
 				/* ----------
 				 * The query string built is
-				 *	DELETE FROM ONLY <fktable> WHERE $1 = fkatt1 [AND ...]
+				 *	DELETE FROM [ONLY] <fktable> WHERE $1 = fkatt1 [AND ...]
 				 * The type id's for the $ parameters are those of the
 				 * corresponding PK attributes.
 				 * ----------
 				 */
 				initStringInfo(&querybuf);
+				fk_only = fk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
+					"" : "ONLY ";
 				quoteRelationName(fkrelname, fk_rel);
-				appendStringInfo(&querybuf, "DELETE FROM ONLY %s", fkrelname);
+				appendStringInfo(&querybuf, "DELETE FROM %s%s",
+								 fk_only, fkrelname);
 				querysep = "WHERE";
 				for (i = 0; i < riinfo->nkeys; i++)
 				{
@@ -1118,10 +1125,11 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
 				const char *querysep;
 				const char *qualsep;
 				Oid			queryoids[RI_MAX_NUMKEYS * 2];
+				const char *fk_only;
 
 				/* ----------
 				 * The query string built is
-				 *	UPDATE ONLY <fktable> SET fkatt1 = $1 [, ...]
+				 *	UPDATE [ONLY] <fktable> SET fkatt1 = $1 [, ...]
 				 *			WHERE $n = fkatt1 [AND ...]
 				 * The type id's for the $ parameters are those of the
 				 * corresponding PK attributes.  Note that we are assuming
@@ -1131,8 +1139,11 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
 				 */
 				initStringInfo(&querybuf);
 				initStringInfo(&qualbuf);
+				fk_only = fk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
+					"" : "ONLY ";
 				quoteRelationName(fkrelname, fk_rel);
-				appendStringInfo(&querybuf, "UPDATE ONLY %s SET", fkrelname);
+				appendStringInfo(&querybuf, "UPDATE %s%s SET",
+								 fk_only, fkrelname);
 				querysep = "";
 				qualsep = "WHERE";
 				for (i = 0, j = riinfo->nkeys; i < riinfo->nkeys; i++, j++)
@@ -1337,11 +1348,12 @@ ri_setnull(TriggerData *trigdata)
 				char		paramname[16];
 				const char *querysep;
 				const char *qualsep;
+				const char *fk_only;
 				Oid			queryoids[RI_MAX_NUMKEYS];
 
 				/* ----------
 				 * The query string built is
-				 *	UPDATE ONLY <fktable> SET fkatt1 = NULL [, ...]
+				 *	UPDATE [ONLY] <fktable> SET fkatt1 = NULL [, ...]
 				 *			WHERE $1 = fkatt1 [AND ...]
 				 * The type id's for the $ parameters are those of the
 				 * corresponding PK attributes.
@@ -1349,8 +1361,11 @@ ri_setnull(TriggerData *trigdata)
 				 */
 				initStringInfo(&querybuf);
 				initStringInfo(&qualbuf);
+				fk_only = fk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
+					"" : "ONLY ";
 				quoteRelationName(fkrelname, fk_rel);
-				appendStringInfo(&querybuf, "UPDATE ONLY %s SET", fkrelname);
+				appendStringInfo(&querybuf, "UPDATE %s%s SET",
+								 fk_only, fkrelname);
 				querysep = "";
 				qualsep = "WHERE";
 				for (i = 0; i < riinfo->nkeys; i++)
@@ -1554,11 +1569,12 @@ ri_setdefault(TriggerData *trigdata)
 				const char *querysep;
 				const char *qualsep;
 				Oid			queryoids[RI_MAX_NUMKEYS];
+				const char *fk_only;
 				int			i;
 
 				/* ----------
 				 * The query string built is
-				 *	UPDATE ONLY <fktable> SET fkatt1 = DEFAULT [, ...]
+				 *	UPDATE [ONLY] <fktable> SET fkatt1 = DEFAULT [, ...]
 				 *			WHERE $1 = fkatt1 [AND ...]
 				 * The type id's for the $ parameters are those of the
 				 * corresponding PK attributes.
@@ -1567,7 +1583,10 @@ ri_setdefault(TriggerData *trigdata)
 				initStringInfo(&querybuf);
 				initStringInfo(&qualbuf);
 				quoteRelationName(fkrelname, fk_rel);
-				appendStringInfo(&querybuf, "UPDATE ONLY %s SET", fkrelname);
+				fk_only = fk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
+					"" : "ONLY ";
+				appendStringInfo(&querybuf, "UPDATE %s%s SET",
+								 fk_only, fkrelname);
 				querysep = "";
 				qualsep = "WHERE";
 				for (i = 0; i < riinfo->nkeys; i++)
@@ -1838,6 +1857,7 @@ RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
 	RangeTblEntry *pkrte;
 	RangeTblEntry *fkrte;
 	const char *sep;
+	const char *fk_only;
 	int			i;
 	int			save_nestlevel;
 	char		workmembuf[32];
@@ -1894,8 +1914,8 @@ RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
 
 	/*----------
 	 * The query string built is:
-	 *	SELECT fk.keycols FROM ONLY relname fk
-	 *	 LEFT OUTER JOIN ONLY pkrelname pk
+	 *	SELECT fk.keycols FROM [ONLY] relname fk
+	 *	 LEFT OUTER JOIN pkrelname pk
 	 *	 ON (pk.pkkeycol1=fk.keycol1 [AND ...])
 	 *	 WHERE pk.pkkeycol1 IS NULL AND
 	 * For MATCH SIMPLE:
@@ -1920,9 +1940,11 @@ RI_Initial_Check(Trigger *trigger, Relation fk_rel, Relation pk_rel)
 
 	quoteRelationName(pkrelname, pk_rel);
 	quoteRelationName(fkrelname, fk_rel);
+	fk_only = fk_rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE ?
+		"" : "ONLY ";
 	appendStringInfo(&querybuf,
-					 " FROM ONLY %s fk LEFT OUTER JOIN ONLY %s pk ON",
-					 fkrelname, pkrelname);
+					 " FROM %s%s fk LEFT OUTER JOIN %s pk ON",
+					 fk_only, fkrelname, pkrelname);
 
 	strcpy(pkattname, "pk.");
 	strcpy(fkattname, "fk.");
@@ -2298,13 +2320,6 @@ ri_FetchConstraintInfo(Trigger *trigger, Relation trig_rel, bool rel_is_pk)
 			elog(ERROR, "wrong pg_constraint entry for trigger \"%s\" on table \"%s\"",
 				 trigger->tgname, RelationGetRelationName(trig_rel));
 	}
-	else
-	{
-		if (riinfo->fk_relid != RelationGetRelid(trig_rel) ||
-			riinfo->pk_relid != trigger->tgconstrrelid)
-			elog(ERROR, "wrong pg_constraint entry for trigger \"%s\" on table \"%s\"",
-				 trigger->tgname, RelationGetRelationName(trig_rel));
-	}
 
 	return riinfo;
 }

src/bin/pg_dump/pg_dump.c

@@ -7116,13 +7116,23 @@ getConstraints(Archive *fout, TableInfo tblinfo[], int numTables)
 					  tbinfo->dobj.name);
 
 		resetPQExpBuffer(query);
-		appendPQExpBuffer(query,
-						  "SELECT tableoid, oid, conname, confrelid, "
-						  "pg_catalog.pg_get_constraintdef(oid) AS condef "
-						  "FROM pg_catalog.pg_constraint "
-						  "WHERE conrelid = '%u'::pg_catalog.oid "
-						  "AND contype = 'f'",
-						  tbinfo->dobj.catId.oid);
+		if (fout->remoteVersion >= 110000)
+			appendPQExpBuffer(query,
+							  "SELECT tableoid, oid, conname, confrelid, "
+							  "pg_catalog.pg_get_constraintdef(oid) AS condef "
+							  "FROM pg_catalog.pg_constraint "
+							  "WHERE conrelid = '%u'::pg_catalog.oid "
+							  "AND conparentid = 0 "
+							  "AND contype = 'f'",
+							  tbinfo->dobj.catId.oid);
+		else
+			appendPQExpBuffer(query,
+							  "SELECT tableoid, oid, conname, confrelid, "
+							  "pg_catalog.pg_get_constraintdef(oid) AS condef "
+							  "FROM pg_catalog.pg_constraint "
+							  "WHERE conrelid = '%u'::pg_catalog.oid "
+							  "AND contype = 'f'",
+							  tbinfo->dobj.catId.oid);
 		res = ExecuteSqlQuery(fout, query->data, PGRES_TUPLES_OK);
 
 		ntups = PQntuples(res);
@@ -16374,18 +16384,28 @@ dumpConstraint(Archive *fout, ConstraintInfo *coninfo)
 	}
 	else if (coninfo->contype == 'f')
 	{
+		char *only;
+
+		/*
+		 * Foreign keys on partitioned tables are always declared as inheriting
+		 * to partitions; for all other cases, emit them as applying ONLY
+		 * directly to the named table, because that's how they work for
+		 * regular inherited tables.
+		 */
+		only = tbinfo->relkind == RELKIND_PARTITIONED_TABLE ? "" : "ONLY ";
+
 		/*
 		 * XXX Potentially wrap in a 'SET CONSTRAINTS OFF' block so that the
 		 * current table data is not processed
 		 */
-		appendPQExpBuffer(q, "ALTER TABLE ONLY %s\n",
-						  fmtQualifiedDumpable(tbinfo));
+		appendPQExpBuffer(q, "ALTER TABLE %s%s\n",
+						  only, fmtQualifiedDumpable(tbinfo));
 		appendPQExpBuffer(q, "    ADD CONSTRAINT %s %s;\n",
 						  fmtId(coninfo->dobj.name),
 						  coninfo->condef);
 
-		appendPQExpBuffer(delq, "ALTER TABLE ONLY %s ",
-						  fmtQualifiedDumpable(tbinfo));
+		appendPQExpBuffer(delq, "ALTER TABLE %s%s ",
+						  only, fmtQualifiedDumpable(tbinfo));
 		appendPQExpBuffer(delq, "DROP CONSTRAINT %s;\n",
 						  fmtId(coninfo->dobj.name));
 

src/include/catalog/pg_constraint_fn.h

@@ -27,6 +27,19 @@ typedef enum ConstraintCategory
 	CONSTRAINT_ASSERTION		/* for future expansion */
 } ConstraintCategory;
 
+/*
+ * Used when cloning a foreign key constraint to a partition, so that the
+ * caller can optionally set up a verification pass for it.
+ */
+typedef struct ClonedConstraint
+{
+	Oid		relid;
+	Oid		refrelid;
+	Oid		conindid;
+	Oid		conid;
+	Constraint *constraint;
+} ClonedConstraint;
+
 extern Oid CreateConstraintEntry(const char *constraintName,
 					  Oid constraintNamespace,
 					  char constraintType,
@@ -57,6 +70,9 @@ extern Oid CreateConstraintEntry(const char *constraintName,
 					  bool conNoInherit,
 					  bool is_internal);
 
+extern void CloneForeignKeyConstraints(Oid parentId, Oid relationId,
+						   List **cloned);
+
 extern void RemoveConstraintById(Oid conId);
 extern void RenameConstraintById(Oid conId, const char *newname);
 

src/include/commands/tablecmds.h

@@ -74,6 +74,10 @@ extern void find_composite_type_dependencies(Oid typeOid,
 
 extern void check_of_type(HeapTuple typetuple);
 
+extern void createForeignKeyTriggers(Relation rel, Oid refRelOid,
+						 Constraint *fkconstraint, Oid constraintOid,
+						 Oid indexOid, bool create_action);
+
 extern void register_on_commit_action(Oid relid, OnCommitAction action);
 extern void remove_on_commit_action(Oid relid);
 

src/test/regress/expected/alter_table.out

@@ -3305,10 +3305,6 @@ CREATE TABLE partitioned (
 	a int,
 	b int
 ) PARTITION BY RANGE (a, (a+b+1));
-ALTER TABLE partitioned ADD FOREIGN KEY (a) REFERENCES blah;
-ERROR:  foreign key constraints are not supported on partitioned tables
-LINE 1: ALTER TABLE partitioned ADD FOREIGN KEY (a) REFERENCES blah;
-                                    ^
 ALTER TABLE partitioned ADD EXCLUDE USING gist (a WITH &&);
 ERROR:  exclusion constraints are not supported on partitioned tables
 LINE 1: ALTER TABLE partitioned ADD EXCLUDE USING gist (a WITH &&);

src/test/regress/expected/create_table.out

@@ -281,16 +281,6 @@ CREATE TABLE partitioned (
 ) PARTITION BY LIST (a1, a2);	-- fail
 ERROR:  cannot use "list" partition strategy with more than one column
 -- unsupported constraint type for partitioned tables
-CREATE TABLE pkrel (
-	a int PRIMARY KEY
-);
-CREATE TABLE partitioned (
-	a int REFERENCES pkrel(a)
-) PARTITION BY RANGE (a);
-ERROR:  foreign key constraints are not supported on partitioned tables
-LINE 2:  a int REFERENCES pkrel(a)
-               ^
-DROP TABLE pkrel;
 CREATE TABLE partitioned (
 	a int,
 	EXCLUDE USING gist (a WITH &&)

src/test/regress/expected/inherit.out

@@ -1209,6 +1209,31 @@ Inherits: test_foreign_constraints
 DROP TABLE test_foreign_constraints_inh;
 DROP TABLE test_foreign_constraints;
 DROP TABLE test_primary_constraints;
+-- Test foreign key behavior
+create table inh_fk_1 (a int primary key);
+insert into inh_fk_1 values (1), (2), (3);
+create table inh_fk_2 (x int primary key, y int references inh_fk_1 on delete cascade);
+insert into inh_fk_2 values (11, 1), (22, 2), (33, 3);
+create table inh_fk_2_child () inherits (inh_fk_2);
+insert into inh_fk_2_child values (111, 1), (222, 2);
+delete from inh_fk_1 where a = 1;
+select * from inh_fk_1 order by 1;
+ a 
+---
+ 2
+ 3
+(2 rows)
+
+select * from inh_fk_2 order by 1, 2;
+  x  | y 
+-----+---
+  22 | 2
+  33 | 3
+ 111 | 1
+ 222 | 2
+(4 rows)
+
+drop table inh_fk_1, inh_fk_2, inh_fk_2_child;
 -- Test that parent and child CHECK constraints can be created in either order
 create table p1(f1 int);
 create table p1_c1() inherits(p1);

src/test/regress/sql/alter_table.sql

@@ -2035,7 +2035,6 @@ CREATE TABLE partitioned (
 	a int,
 	b int
 ) PARTITION BY RANGE (a, (a+b+1));
-ALTER TABLE partitioned ADD FOREIGN KEY (a) REFERENCES blah;
 ALTER TABLE partitioned ADD EXCLUDE USING gist (a WITH &&);
 
 -- cannot drop column that is part of the partition key

src/test/regress/sql/create_table.sql

@@ -298,14 +298,6 @@ CREATE TABLE partitioned (
 ) PARTITION BY LIST (a1, a2);	-- fail
 
 -- unsupported constraint type for partitioned tables
-CREATE TABLE pkrel (
-	a int PRIMARY KEY
-);
-CREATE TABLE partitioned (
-	a int REFERENCES pkrel(a)
-) PARTITION BY RANGE (a);
-DROP TABLE pkrel;
-
 CREATE TABLE partitioned (
 	a int,
 	EXCLUDE USING gist (a WITH &&)

src/test/regress/sql/foreign_key.sql

@@ -1065,3 +1065,157 @@ alter table fktable2 drop constraint fktable2_f1_fkey;
 commit;
 
 drop table pktable2, fktable2;
+
+
+--
+-- Foreign keys and partitioned tables
+--
+
+-- partitioned table in the referenced side are not allowed
+CREATE TABLE fk_partitioned_pk (a int, b int, primary key (a, b))
+  PARTITION BY RANGE (a, b);
+-- verify with create table first ...
+CREATE TABLE fk_notpartitioned_fk (a int, b int,
+  FOREIGN KEY (a, b) REFERENCES fk_partitioned_pk);
+-- and then with alter table.
+CREATE TABLE fk_notpartitioned_fk_2 (a int, b int);
+ALTER TABLE fk_notpartitioned_fk_2 ADD FOREIGN KEY (a, b)
+  REFERENCES fk_partitioned_pk;
+DROP TABLE fk_partitioned_pk, fk_notpartitioned_fk_2;
+
+-- Creation of a partitioned hierarchy with irregular definitions
+CREATE TABLE fk_notpartitioned_pk (fdrop1 int, a int, fdrop2 int, b int,
+  PRIMARY KEY (a, b));
+ALTER TABLE fk_notpartitioned_pk DROP COLUMN fdrop1, DROP COLUMN fdrop2;
+CREATE TABLE fk_partitioned_fk (b int, fdrop1 int, a int) PARTITION BY RANGE (a, b);
+ALTER TABLE fk_partitioned_fk DROP COLUMN fdrop1;
+CREATE TABLE fk_partitioned_fk_1 (fdrop1 int, fdrop2 int, a int, fdrop3 int, b int);
+ALTER TABLE fk_partitioned_fk_1 DROP COLUMN fdrop1, DROP COLUMN fdrop2, DROP COLUMN fdrop3;
+ALTER TABLE fk_partitioned_fk ATTACH PARTITION fk_partitioned_fk_1 FOR VALUES FROM (0,0) TO (1000,1000);
+ALTER TABLE fk_partitioned_fk ADD FOREIGN KEY (a, b) REFERENCES fk_notpartitioned_pk;
+CREATE TABLE fk_partitioned_fk_2 (b int, fdrop1 int, fdrop2 int, a int);
+ALTER TABLE fk_partitioned_fk_2 DROP COLUMN fdrop1, DROP COLUMN fdrop2;
+ALTER TABLE fk_partitioned_fk ATTACH PARTITION fk_partitioned_fk_2 FOR VALUES FROM (1000,1000) TO (2000,2000);
+
+CREATE TABLE fk_partitioned_fk_3 (fdrop1 int, fdrop2 int, fdrop3 int, fdrop4 int, b int, a int)
+  PARTITION BY HASH (a);
+ALTER TABLE fk_partitioned_fk_3 DROP COLUMN fdrop1, DROP COLUMN fdrop2,
+	DROP COLUMN fdrop3, DROP COLUMN fdrop4;
+CREATE TABLE fk_partitioned_fk_3_0 PARTITION OF fk_partitioned_fk_3 FOR VALUES WITH (MODULUS 5, REMAINDER 0);
+CREATE TABLE fk_partitioned_fk_3_1 PARTITION OF fk_partitioned_fk_3 FOR VALUES WITH (MODULUS 5, REMAINDER 1);
+ALTER TABLE fk_partitioned_fk ATTACH PARTITION fk_partitioned_fk_3
+  FOR VALUES FROM (2000,2000) TO (3000,3000);
+
+-- these inserts, targetting both the partition directly as well as the
+-- partitioned table, should all fail
+INSERT INTO fk_partitioned_fk (a,b) VALUES (500, 501);
+INSERT INTO fk_partitioned_fk_1 (a,b) VALUES (500, 501);
+INSERT INTO fk_partitioned_fk (a,b) VALUES (1500, 1501);
+INSERT INTO fk_partitioned_fk_2 (a,b) VALUES (1500, 1501);
+INSERT INTO fk_partitioned_fk (a,b) VALUES (2500, 2502);
+INSERT INTO fk_partitioned_fk_3 (a,b) VALUES (2500, 2502);
+INSERT INTO fk_partitioned_fk (a,b) VALUES (2501, 2503);
+INSERT INTO fk_partitioned_fk_3 (a,b) VALUES (2501, 2503);
+
+-- but if we insert the values that make them valid, then they work
+INSERT INTO fk_notpartitioned_pk VALUES (500, 501), (1500, 1501),
+  (2500, 2502), (2501, 2503);
+INSERT INTO fk_partitioned_fk (a,b) VALUES (500, 501);
+INSERT INTO fk_partitioned_fk (a,b) VALUES (1500, 1501);
+INSERT INTO fk_partitioned_fk (a,b) VALUES (2500, 2502);
+INSERT INTO fk_partitioned_fk (a,b) VALUES (2501, 2503);
+
+-- this update fails because there is no referenced row
+UPDATE fk_partitioned_fk SET a = a + 1 WHERE a = 2501;
+-- but we can fix it thusly:
+INSERT INTO fk_notpartitioned_pk (a,b) VALUES (2502, 2503);
+UPDATE fk_partitioned_fk SET a = a + 1 WHERE a = 2501;
+
+-- these updates would leave lingering rows in the referencing table; disallow
+UPDATE fk_notpartitioned_pk SET b = 502 WHERE a = 500;
+UPDATE fk_notpartitioned_pk SET b = 1502 WHERE a = 1500;
+UPDATE fk_notpartitioned_pk SET b = 2504 WHERE a = 2500;
+ALTER TABLE fk_partitioned_fk DROP CONSTRAINT fk_partitioned_fk_a_fkey;
+-- done.
+DROP TABLE fk_notpartitioned_pk, fk_partitioned_fk;
+
+-- Test some other exotic foreign key features: MATCH SIMPLE, ON UPDATE/DELETE
+-- actions
+CREATE TABLE fk_notpartitioned_pk (a int, b int, primary key (a, b));
+CREATE TABLE fk_partitioned_fk (a int default 2501, b int default 142857) PARTITION BY LIST (a);
+CREATE TABLE fk_partitioned_fk_1 PARTITION OF fk_partitioned_fk FOR VALUES IN (NULL,500,501,502);
+ALTER TABLE fk_partitioned_fk ADD FOREIGN KEY (a, b)
+  REFERENCES fk_notpartitioned_pk MATCH SIMPLE
+  ON DELETE SET NULL ON UPDATE SET NULL;
+CREATE TABLE fk_partitioned_fk_2 PARTITION OF fk_partitioned_fk FOR VALUES IN (1500,1502);
+CREATE TABLE fk_partitioned_fk_3 (a int, b int);
+ALTER TABLE fk_partitioned_fk ATTACH PARTITION fk_partitioned_fk_3 FOR VALUES IN (2500,2501,2502,2503);
+
+-- this insert fails
+INSERT INTO fk_partitioned_fk (a, b) VALUES (2502, 2503);
+INSERT INTO fk_partitioned_fk_3 (a, b) VALUES (2502, 2503);
+-- but since the FK is MATCH SIMPLE, this one doesn't
+INSERT INTO fk_partitioned_fk_3 (a, b) VALUES (2502, NULL);
+-- now create the referenced row ...
+INSERT INTO fk_notpartitioned_pk VALUES (2502, 2503);
+--- and now the same insert work
+INSERT INTO fk_partitioned_fk_3 (a, b) VALUES (2502, 2503);
+-- this always works
+INSERT INTO fk_partitioned_fk (a,b) VALUES (NULL, NULL);
+
+-- ON UPDATE SET NULL
+SELECT tableoid::regclass, a, b FROM fk_partitioned_fk WHERE b IS NULL ORDER BY a;
+UPDATE fk_notpartitioned_pk SET a = a + 1 WHERE a = 2502;
+SELECT tableoid::regclass, a, b FROM fk_partitioned_fk WHERE b IS NULL ORDER BY a;
+
+-- ON DELETE SET NULL
+INSERT INTO fk_partitioned_fk VALUES (2503, 2503);
+SELECT count(*) FROM fk_partitioned_fk WHERE a IS NULL;
+DELETE FROM fk_notpartitioned_pk;
+SELECT count(*) FROM fk_partitioned_fk WHERE a IS NULL;
+
+-- ON UPDATE/DELETE SET DEFAULT
+ALTER TABLE fk_partitioned_fk DROP CONSTRAINT fk_partitioned_fk_a_fkey;
+ALTER TABLE fk_partitioned_fk ADD FOREIGN KEY (a, b)
+  REFERENCES fk_notpartitioned_pk
+  ON DELETE SET DEFAULT ON UPDATE SET DEFAULT;
+INSERT INTO fk_notpartitioned_pk VALUES (2502, 2503);
+INSERT INTO fk_partitioned_fk_3 (a, b) VALUES (2502, 2503);
+-- this fails, because the defaults for the referencing table are not present
+-- in the referenced table:
+UPDATE fk_notpartitioned_pk SET a = 1500 WHERE a = 2502;
+-- but inserting the row we can make it work:
+INSERT INTO fk_notpartitioned_pk VALUES (2501, 142857);
+UPDATE fk_notpartitioned_pk SET a = 1500 WHERE a = 2502;
+SELECT * FROM fk_partitioned_fk WHERE b = 142857;
+
+-- ON UPDATE/DELETE CASCADE
+ALTER TABLE fk_partitioned_fk DROP CONSTRAINT fk_partitioned_fk_a_fkey;
+ALTER TABLE fk_partitioned_fk ADD FOREIGN KEY (a, b)
+  REFERENCES fk_notpartitioned_pk
+  ON DELETE CASCADE ON UPDATE CASCADE;
+UPDATE fk_notpartitioned_pk SET a = 2502 WHERE a = 2501;
+SELECT * FROM fk_partitioned_fk WHERE b = 142857;
+
+-- Now you see it ...
+SELECT * FROM fk_partitioned_fk WHERE b = 142857;
+DELETE FROM fk_notpartitioned_pk WHERE b = 142857;
+-- now you don't.
+SELECT * FROM fk_partitioned_fk WHERE a = 142857;
+
+-- verify that DROP works
+DROP TABLE fk_partitioned_fk_2;
+
+-- verify that attaching a table checks that the existing data satisfies the
+-- constraint
+CREATE TABLE fk_partitioned_fk_2 (a int, b int) PARTITION BY RANGE (b);
+CREATE TABLE fk_partitioned_fk_2_1 PARTITION OF fk_partitioned_fk_2 FOR VALUES FROM (0) TO (1000);
+CREATE TABLE fk_partitioned_fk_2_2 PARTITION OF fk_partitioned_fk_2 FOR VALUES FROM (1000) TO (2000);
+INSERT INTO fk_partitioned_fk_2 VALUES (1600, 601), (1600, 1601);
+ALTER TABLE fk_partitioned_fk ATTACH PARTITION fk_partitioned_fk_2
+  FOR VALUES IN (1600);
+INSERT INTO fk_notpartitioned_pk VALUES (1600, 601), (1600, 1601);
+ALTER TABLE fk_partitioned_fk ATTACH PARTITION fk_partitioned_fk_2
+  FOR VALUES IN (1600);
+
+-- leave these tables around intentionally

src/test/regress/sql/inherit.sql

@@ -409,6 +409,18 @@ DROP TABLE test_foreign_constraints_inh;
 DROP TABLE test_foreign_constraints;
 DROP TABLE test_primary_constraints;
 
+-- Test foreign key behavior
+create table inh_fk_1 (a int primary key);
+insert into inh_fk_1 values (1), (2), (3);
+create table inh_fk_2 (x int primary key, y int references inh_fk_1 on delete cascade);
+insert into inh_fk_2 values (11, 1), (22, 2), (33, 3);
+create table inh_fk_2_child () inherits (inh_fk_2);
+insert into inh_fk_2_child values (111, 1), (222, 2);
+delete from inh_fk_1 where a = 1;
+select * from inh_fk_1 order by 1;
+select * from inh_fk_2 order by 1, 2;
+drop table inh_fk_1, inh_fk_2, inh_fk_2_child;
+
 -- Test that parent and child CHECK constraints can be created in either order
 create table p1(f1 int);
 create table p1_c1() inherits(p1);