v1-0002-add-sql-support.patch

diff --git a/doc/src/sgml/keywords.sgml b/doc/src/sgml/keywords.sgml
index a37d0b7..fa32a88 100644
--- a/doc/src/sgml/keywords.sgml
+++ b/doc/src/sgml/keywords.sgml
@@ -4522,6 +4522,13 @@
     <entry>reserved</entry>
    </row>
    <row>
+    <entry><token>SUPPORT</token></entry>
+    <entry>non-reserved</entry>
+    <entry></entry>
+    <entry></entry>
+    <entry></entry>
+   </row>
+   <row>
     <entry><token>SYMMETRIC</token></entry>
     <entry>reserved</entry>
     <entry>reserved</entry>
diff --git a/doc/src/sgml/ref/alter_function.sgml b/doc/src/sgml/ref/alter_function.sgml
index d8747e0..03ffa59 100644
--- a/doc/src/sgml/ref/alter_function.sgml
+++ b/doc/src/sgml/ref/alter_function.sgml
@@ -40,6 +40,7 @@ ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="param
     PARALLEL { UNSAFE | RESTRICTED | SAFE }
     COST <replaceable class="parameter">execution_cost</replaceable>
     ROWS <replaceable class="parameter">result_rows</replaceable>
+    SUPPORT <replaceable class="parameter">support_function</replaceable>
     SET <replaceable class="parameter">configuration_parameter</replaceable> { TO | = } { <replaceable class="parameter">value</replaceable> | DEFAULT }
     SET <replaceable class="parameter">configuration_parameter</replaceable> FROM CURRENT
     RESET <replaceable class="parameter">configuration_parameter</replaceable>
@@ -248,6 +249,24 @@ ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="param
      </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term><literal>SUPPORT</literal> <replaceable class="parameter">support_function</replaceable></term>
+
+    <listitem>
+     <para>
+      Set or change the planner support function to use for this function.
+      See <xref linkend="xfunc-optimization"/> for details.  You must be
+      superuser to use this option.
+     </para>
+
+     <para>
+      This option cannot be used to remove the support function altogether,
+      since it must name a new support function.  Use <command>CREATE OR
+      REPLACE FUNCTION</command> if you need to do that.
+     </para>
+    </listitem>
+   </varlistentry>
+
      <varlistentry>
       <term><replaceable>configuration_parameter</replaceable></term>
       <term><replaceable>value</replaceable></term>
diff --git a/doc/src/sgml/ref/create_function.sgml b/doc/src/sgml/ref/create_function.sgml
index 4072543..dd6a2f7 100644
--- a/doc/src/sgml/ref/create_function.sgml
+++ b/doc/src/sgml/ref/create_function.sgml
@@ -33,6 +33,7 @@ CREATE [ OR REPLACE ] FUNCTION
     | PARALLEL { UNSAFE | RESTRICTED | SAFE }
     | COST <replaceable class="parameter">execution_cost</replaceable>
     | ROWS <replaceable class="parameter">result_rows</replaceable>
+    | SUPPORT <replaceable class="parameter">support_function</replaceable>
     | SET <replaceable class="parameter">configuration_parameter</replaceable> { TO <replaceable class="parameter">value</replaceable> | = <replaceable class="parameter">value</replaceable> | FROM CURRENT }
     | AS '<replaceable class="parameter">definition</replaceable>'
     | AS '<replaceable class="parameter">obj_file</replaceable>', '<replaceable class="parameter">link_symbol</replaceable>'
@@ -478,6 +479,19 @@ CREATE [ OR REPLACE ] FUNCTION
     </varlistentry>
 
     <varlistentry>
+     <term><literal>SUPPORT</literal> <replaceable class="parameter">support_function</replaceable></term>
+
+     <listitem>
+      <para>
+       The name (optionally schema-qualified) of a <firstterm>planner support
+       function</firstterm> to use for this function.  See
+       <xref linkend="xfunc-optimization"/> for details.
+       You must be superuser to use this option.
+      </para>
+     </listitem>
+    </varlistentry>
+
+    <varlistentry>
      <term><replaceable>configuration_parameter</replaceable></term>
      <term><replaceable>value</replaceable></term>
      <listitem>
diff --git a/src/backend/catalog/pg_aggregate.c b/src/backend/catalog/pg_aggregate.c
index cc3806e..19e3171 100644
--- a/src/backend/catalog/pg_aggregate.c
+++ b/src/backend/catalog/pg_aggregate.c
@@ -632,6 +632,7 @@ AggregateCreate(const char *aggName,
 							 parameterDefaults, /* parameterDefaults */
 							 PointerGetDatum(NULL), /* trftypes */
 							 PointerGetDatum(NULL), /* proconfig */
+							 InvalidOid,	/* no prosupport */
 							 1, /* procost */
 							 0);	/* prorows */
 	procOid = myself.objectId;
diff --git a/src/backend/catalog/pg_depend.c b/src/backend/catalog/pg_depend.c
index 2b8f651..23b01f8 100644
--- a/src/backend/catalog/pg_depend.c
+++ b/src/backend/catalog/pg_depend.c
@@ -286,9 +286,12 @@ deleteDependencyRecordsForClass(Oid classId, Oid objectId,
  * newRefObjectId is the new referenced object (must be of class refClassId).
  *
  * Note the lack of objsubid parameters.  If there are subobject references
- * they will all be readjusted.
+ * they will all be readjusted.  Also, there is an expectation that we are
+ * dealing with NORMAL dependencies: if we have to replace an (implicit)
+ * dependency on a pinned object with an explicit dependency on an unpinned
+ * one, the new one will be NORMAL.
  *
- * Returns the number of records updated.
+ * Returns the number of records updated -- zero indicates a problem.
  */
 long
 changeDependencyFor(Oid classId, Oid objectId,
@@ -301,35 +304,52 @@ changeDependencyFor(Oid classId, Oid objectId,
 	SysScanDesc scan;
 	HeapTuple	tup;
 	ObjectAddress objAddr;
+	ObjectAddress depAddr;
+	bool		oldIsPinned;
 	bool		newIsPinned;
 
 	depRel = table_open(DependRelationId, RowExclusiveLock);
 
 	/*
-	 * If oldRefObjectId is pinned, there won't be any dependency entries on
-	 * it --- we can't cope in that case.  (This isn't really worth expending
-	 * code to fix, in current usage; it just means you can't rename stuff out
-	 * of pg_catalog, which would likely be a bad move anyway.)
+	 * Check to see if either oldRefObjectId or newRefObjectId is pinned.
+	 * Pinned objects should not have any dependency entries pointing to them,
+	 * so in these cases we should add or remove a pg_depend entry, or do
+	 * nothing at all, rather than update an entry as in the normal case.
 	 */
 	objAddr.classId = refClassId;
 	objAddr.objectId = oldRefObjectId;
 	objAddr.objectSubId = 0;
 
-	if (isObjectPinned(&objAddr, depRel))
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("cannot remove dependency on %s because it is a system object",
-						getObjectDescription(&objAddr))));
+	oldIsPinned = isObjectPinned(&objAddr, depRel);
 
-	/*
-	 * We can handle adding a dependency on something pinned, though, since
-	 * that just means deleting the dependency entry.
-	 */
 	objAddr.objectId = newRefObjectId;
 
 	newIsPinned = isObjectPinned(&objAddr, depRel);
 
-	/* Now search for dependency records */
+	if (oldIsPinned)
+	{
+		table_close(depRel, RowExclusiveLock);
+
+		/*
+		 * If both are pinned, we need do nothing.  However, return 1 not 0,
+		 * else callers will think this is an error case.
+		 */
+		if (newIsPinned)
+			return 1;
+
+		/*
+		 * There is no old dependency record, but we should insert a new one.
+		 * Assume a normal dependency is wanted.
+		 */
+		depAddr.classId = classId;
+		depAddr.objectId = objectId;
+		depAddr.objectSubId = 0;
+		recordDependencyOn(&depAddr, &objAddr, DEPENDENCY_NORMAL);
+
+		return 1;
+	}
+
+	/* There should be existing dependency record(s), so search. */
 	ScanKeyInit(&key[0],
 				Anum_pg_depend_classid,
 				BTEqualStrategyNumber, F_OIDEQ,
diff --git a/src/backend/catalog/pg_proc.c b/src/backend/catalog/pg_proc.c
index 3a86f1e..557e0ea 100644
--- a/src/backend/catalog/pg_proc.c
+++ b/src/backend/catalog/pg_proc.c
@@ -88,6 +88,7 @@ ProcedureCreate(const char *procedureName,
 				List *parameterDefaults,
 				Datum trftypes,
 				Datum proconfig,
+				Oid prosupport,
 				float4 procost,
 				float4 prorows)
 {
@@ -319,7 +320,7 @@ ProcedureCreate(const char *procedureName,
 	values[Anum_pg_proc_procost - 1] = Float4GetDatum(procost);
 	values[Anum_pg_proc_prorows - 1] = Float4GetDatum(prorows);
 	values[Anum_pg_proc_provariadic - 1] = ObjectIdGetDatum(variadicType);
-	values[Anum_pg_proc_prosupport - 1] = ObjectIdGetDatum(InvalidOid);
+	values[Anum_pg_proc_prosupport - 1] = ObjectIdGetDatum(prosupport);
 	values[Anum_pg_proc_prokind - 1] = CharGetDatum(prokind);
 	values[Anum_pg_proc_prosecdef - 1] = BoolGetDatum(security_definer);
 	values[Anum_pg_proc_proleakproof - 1] = BoolGetDatum(isLeakProof);
@@ -656,6 +657,15 @@ ProcedureCreate(const char *procedureName,
 		recordDependencyOnExpr(&myself, (Node *) parameterDefaults,
 							   NIL, DEPENDENCY_NORMAL);
 
+	/* dependency on support function, if any */
+	if (OidIsValid(prosupport))
+	{
+		referenced.classId = ProcedureRelationId;
+		referenced.objectId = prosupport;
+		referenced.objectSubId = 0;
+		recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
+	}
+
 	/* dependency on owner */
 	if (!is_update)
 		recordDependencyOnOwner(ProcedureRelationId, retval, proowner);
diff --git a/src/backend/commands/functioncmds.c b/src/backend/commands/functioncmds.c
index eae2b09..4b13fdb 100644
--- a/src/backend/commands/functioncmds.c
+++ b/src/backend/commands/functioncmds.c
@@ -480,6 +480,7 @@ compute_common_attribute(ParseState *pstate,
 						 List **set_items,
 						 DefElem **cost_item,
 						 DefElem **rows_item,
+						 DefElem **support_item,
 						 DefElem **parallel_item)
 {
 	if (strcmp(defel->defname, "volatility") == 0)
@@ -538,6 +539,15 @@ compute_common_attribute(ParseState *pstate,
 
 		*rows_item = defel;
 	}
+	else if (strcmp(defel->defname, "support") == 0)
+	{
+		if (is_procedure)
+			goto procedure_error;
+		if (*support_item)
+			goto duplicate_error;
+
+		*support_item = defel;
+	}
 	else if (strcmp(defel->defname, "parallel") == 0)
 	{
 		if (is_procedure)
@@ -636,6 +646,45 @@ update_proconfig_value(ArrayType *a, List *set_items)
 	return a;
 }
 
+static Oid
+interpret_func_support(DefElem *defel)
+{
+	List	   *procName = defGetQualifiedName(defel);
+	Oid			procOid;
+	Oid			argList[1];
+
+	/*
+	 * Support functions always take one INTERNAL argument and return
+	 * INTERNAL.
+	 */
+	argList[0] = INTERNALOID;
+
+	procOid = LookupFuncName(procName, 1, argList, true);
+	if (!OidIsValid(procOid))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_FUNCTION),
+				 errmsg("function %s does not exist",
+						func_signature_string(procName, 1, NIL, argList))));
+
+	if (get_func_rettype(procOid) != INTERNALOID)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+				 errmsg("support function %s must return type %s",
+						NameListToString(procName), "internal")));
+
+	/*
+	 * Someday we might want an ACL check here; but for now, we insist that
+	 * you be superuser to specify a support function, so privilege on the
+	 * support function is moot.
+	 */
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to specify a support function")));
+
+	return procOid;
+}
+
 
 /*
  * Dissect the list of options assembled in gram.y into function
@@ -656,6 +705,7 @@ compute_function_attributes(ParseState *pstate,
 							ArrayType **proconfig,
 							float4 *procost,
 							float4 *prorows,
+							Oid *prosupport,
 							char *parallel_p)
 {
 	ListCell   *option;
@@ -670,6 +720,7 @@ compute_function_attributes(ParseState *pstate,
 	List	   *set_items = NIL;
 	DefElem    *cost_item = NULL;
 	DefElem    *rows_item = NULL;
+	DefElem    *support_item = NULL;
 	DefElem    *parallel_item = NULL;
 
 	foreach(option, options)
@@ -727,6 +778,7 @@ compute_function_attributes(ParseState *pstate,
 										  &set_items,
 										  &cost_item,
 										  &rows_item,
+										  &support_item,
 										  &parallel_item))
 		{
 			/* recognized common option */
@@ -789,6 +841,8 @@ compute_function_attributes(ParseState *pstate,
 					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 					 errmsg("ROWS must be positive")));
 	}
+	if (support_item)
+		*prosupport = interpret_func_support(support_item);
 	if (parallel_item)
 		*parallel_p = interpret_func_parallel(parallel_item);
 }
@@ -894,6 +948,7 @@ CreateFunction(ParseState *pstate, CreateFunctionStmt *stmt)
 	ArrayType  *proconfig;
 	float4		procost;
 	float4		prorows;
+	Oid			prosupport;
 	HeapTuple	languageTuple;
 	Form_pg_language languageStruct;
 	List	   *as_clause;
@@ -918,6 +973,7 @@ CreateFunction(ParseState *pstate, CreateFunctionStmt *stmt)
 	proconfig = NULL;
 	procost = -1;				/* indicates not set */
 	prorows = -1;				/* indicates not set */
+	prosupport = InvalidOid;
 	parallel = PROPARALLEL_UNSAFE;
 
 	/* Extract non-default attributes from stmt->options list */
@@ -927,7 +983,8 @@ CreateFunction(ParseState *pstate, CreateFunctionStmt *stmt)
 								&as_clause, &language, &transformDefElem,
 								&isWindowFunc, &volatility,
 								&isStrict, &security, &isLeakProof,
-								&proconfig, &procost, &prorows, &parallel);
+								&proconfig, &procost, &prorows,
+								&prosupport, &parallel);
 
 	/* Look up the language and validate permissions */
 	languageTuple = SearchSysCache1(LANGNAME, PointerGetDatum(language));
@@ -1114,6 +1171,7 @@ CreateFunction(ParseState *pstate, CreateFunctionStmt *stmt)
 						   parameterDefaults,
 						   PointerGetDatum(trftypes),
 						   PointerGetDatum(proconfig),
+						   prosupport,
 						   procost,
 						   prorows);
 }
@@ -1188,6 +1246,7 @@ AlterFunction(ParseState *pstate, AlterFunctionStmt *stmt)
 	List	   *set_items = NIL;
 	DefElem    *cost_item = NULL;
 	DefElem    *rows_item = NULL;
+	DefElem    *support_item = NULL;
 	DefElem    *parallel_item = NULL;
 	ObjectAddress address;
 
@@ -1195,6 +1254,8 @@ AlterFunction(ParseState *pstate, AlterFunctionStmt *stmt)
 
 	funcOid = LookupFuncWithArgs(stmt->objtype, stmt->func, false);
 
+	ObjectAddressSet(address, ProcedureRelationId, funcOid);
+
 	tup = SearchSysCacheCopy1(PROCOID, ObjectIdGetDatum(funcOid));
 	if (!HeapTupleIsValid(tup)) /* should not happen */
 		elog(ERROR, "cache lookup failed for function %u", funcOid);
@@ -1229,6 +1290,7 @@ AlterFunction(ParseState *pstate, AlterFunctionStmt *stmt)
 									 &set_items,
 									 &cost_item,
 									 &rows_item,
+									 &support_item,
 									 &parallel_item) == false)
 			elog(ERROR, "option \"%s\" not recognized", defel->defname);
 	}
@@ -1267,6 +1329,28 @@ AlterFunction(ParseState *pstate, AlterFunctionStmt *stmt)
 					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 					 errmsg("ROWS is not applicable when function does not return a set")));
 	}
+	if (support_item)
+	{
+		/* interpret_func_support handles the privilege check */
+		Oid			newsupport = interpret_func_support(support_item);
+
+		/* Add or replace dependency on support function */
+		if (OidIsValid(procForm->prosupport))
+			changeDependencyFor(ProcedureRelationId, funcOid,
+								ProcedureRelationId, procForm->prosupport,
+								newsupport);
+		else
+		{
+			ObjectAddress referenced;
+
+			referenced.classId = ProcedureRelationId;
+			referenced.objectId = newsupport;
+			referenced.objectSubId = 0;
+			recordDependencyOn(&address, &referenced, DEPENDENCY_NORMAL);
+		}
+
+		procForm->prosupport = newsupport;
+	}
 	if (set_items)
 	{
 		Datum		datum;
@@ -1309,8 +1393,6 @@ AlterFunction(ParseState *pstate, AlterFunctionStmt *stmt)
 
 	InvokeObjectPostAlterHook(ProcedureRelationId, funcOid, 0);
 
-	ObjectAddressSet(address, ProcedureRelationId, funcOid);
-
 	table_close(rel, NoLock);
 	heap_freetuple(tup);
 
diff --git a/src/backend/commands/proclang.c b/src/backend/commands/proclang.c
index c2e9e41..59c4e8d 100644
--- a/src/backend/commands/proclang.c
+++ b/src/backend/commands/proclang.c
@@ -141,6 +141,7 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 									  NIL,
 									  PointerGetDatum(NULL),
 									  PointerGetDatum(NULL),
+									  InvalidOid,
 									  1,
 									  0);
 			handlerOid = tmpAddr.objectId;
@@ -180,6 +181,7 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 										  NIL,
 										  PointerGetDatum(NULL),
 										  PointerGetDatum(NULL),
+										  InvalidOid,
 										  1,
 										  0);
 				inlineOid = tmpAddr.objectId;
@@ -222,6 +224,7 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 										  NIL,
 										  PointerGetDatum(NULL),
 										  PointerGetDatum(NULL),
+										  InvalidOid,
 										  1,
 										  0);
 				valOid = tmpAddr.objectId;
diff --git a/src/backend/commands/typecmds.c b/src/backend/commands/typecmds.c
index 35a6485..b0a61a3 100644
--- a/src/backend/commands/typecmds.c
+++ b/src/backend/commands/typecmds.c
@@ -1664,6 +1664,7 @@ makeRangeConstructors(const char *name, Oid namespace,
 								 NIL,	/* parameterDefaults */
 								 PointerGetDatum(NULL), /* trftypes */
 								 PointerGetDatum(NULL), /* proconfig */
+								 InvalidOid,	/* prosupport */
 								 1.0,	/* procost */
 								 0.0);	/* prorows */
 
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index d8a3c2d..4c5f00d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -677,7 +677,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
 	SERIALIZABLE SERVER SESSION SESSION_USER SET SETS SETOF SHARE SHOW
 	SIMILAR SIMPLE SKIP SMALLINT SNAPSHOT SOME SQL_P STABLE STANDALONE_P
 	START STATEMENT STATISTICS STDIN STDOUT STORAGE STRICT_P STRIP_P
-	SUBSCRIPTION SUBSTRING SYMMETRIC SYSID SYSTEM_P
+	SUBSCRIPTION SUBSTRING SUPPORT SYMMETRIC SYSID SYSTEM_P
 
 	TABLE TABLES TABLESAMPLE TABLESPACE TEMP TEMPLATE TEMPORARY TEXT_P THEN
 	TIES TIME TIMESTAMP TO TRAILING TRANSACTION TRANSFORM
@@ -7888,6 +7888,10 @@ common_func_opt_item:
 				{
 					$$ = makeDefElem("rows", (Node *)$2, @1);
 				}
+			| SUPPORT any_name
+				{
+					$$ = makeDefElem("support", (Node *)$2, @1);
+				}
 			| FunctionSetResetClause
 				{
 					/* we abuse the normal content of a DefElem here */
@@ -15218,6 +15222,7 @@ unreserved_keyword:
 			| STRICT_P
 			| STRIP_P
 			| SUBSCRIPTION
+			| SUPPORT
 			| SYSID
 			| SYSTEM_P
 			| TABLES
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 302df16..4bda11c 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -2638,6 +2638,21 @@ pg_get_functiondef(PG_FUNCTION_ARGS)
 	if (proc->prorows > 0 && proc->prorows != 1000)
 		appendStringInfo(&buf, " ROWS %g", proc->prorows);
 
+	if (proc->prosupport)
+	{
+		Oid			argtypes[1];
+
+		/*
+		 * We should qualify the support function's name if it wouldn't be
+		 * resolved by lookup in the current search path.
+		 */
+		argtypes[0] = INTERNALOID;
+		appendStringInfo(&buf, " SUPPORT %s",
+						 generate_function_name(proc->prosupport, 1,
+												NIL, argtypes,
+												false, NULL, EXPR_KIND_NONE));
+	}
+
 	if (oldlen != buf.len)
 		appendStringInfoChar(&buf, '\n');
 
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 2b1a947..615d997 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -11466,6 +11466,7 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 	char	   *proconfig;
 	char	   *procost;
 	char	   *prorows;
+	char	   *prosupport;
 	char	   *proparallel;
 	char	   *lanname;
 	char	   *rettypename;
@@ -11488,7 +11489,26 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 	asPart = createPQExpBuffer();
 
 	/* Fetch function-specific details */
-	if (fout->remoteVersion >= 110000)
+	if (fout->remoteVersion >= 120000)
+	{
+		/*
+		 * prosupport was added in 12
+		 */
+		appendPQExpBuffer(query,
+						  "SELECT proretset, prosrc, probin, "
+						  "pg_catalog.pg_get_function_arguments(oid) AS funcargs, "
+						  "pg_catalog.pg_get_function_identity_arguments(oid) AS funciargs, "
+						  "pg_catalog.pg_get_function_result(oid) AS funcresult, "
+						  "array_to_string(protrftypes, ' ') AS protrftypes, "
+						  "prokind, provolatile, proisstrict, prosecdef, "
+						  "proleakproof, proconfig, procost, prorows, "
+						  "prosupport, proparallel, "
+						  "(SELECT lanname FROM pg_catalog.pg_language WHERE oid = prolang) AS lanname "
+						  "FROM pg_catalog.pg_proc "
+						  "WHERE oid = '%u'::pg_catalog.oid",
+						  finfo->dobj.catId.oid);
+	}
+	else if (fout->remoteVersion >= 110000)
 	{
 		/*
 		 * prokind was added in 11
@@ -11501,7 +11521,7 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 						  "array_to_string(protrftypes, ' ') AS protrftypes, "
 						  "prokind, provolatile, proisstrict, prosecdef, "
 						  "proleakproof, proconfig, procost, prorows, "
-						  "proparallel, "
+						  "'-' AS prosupport, proparallel, "
 						  "(SELECT lanname FROM pg_catalog.pg_language WHERE oid = prolang) AS lanname "
 						  "FROM pg_catalog.pg_proc "
 						  "WHERE oid = '%u'::pg_catalog.oid",
@@ -11521,7 +11541,7 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 						  "CASE WHEN proiswindow THEN 'w' ELSE 'f' END AS prokind, "
 						  "provolatile, proisstrict, prosecdef, "
 						  "proleakproof, proconfig, procost, prorows, "
-						  "proparallel, "
+						  "'-' AS prosupport, proparallel, "
 						  "(SELECT lanname FROM pg_catalog.pg_language WHERE oid = prolang) AS lanname "
 						  "FROM pg_catalog.pg_proc "
 						  "WHERE oid = '%u'::pg_catalog.oid",
@@ -11541,6 +11561,7 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 						  "CASE WHEN proiswindow THEN 'w' ELSE 'f' END AS prokind, "
 						  "provolatile, proisstrict, prosecdef, "
 						  "proleakproof, proconfig, procost, prorows, "
+						  "'-' AS prosupport, "
 						  "(SELECT lanname FROM pg_catalog.pg_language WHERE oid = prolang) AS lanname "
 						  "FROM pg_catalog.pg_proc "
 						  "WHERE oid = '%u'::pg_catalog.oid",
@@ -11559,6 +11580,7 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 						  "CASE WHEN proiswindow THEN 'w' ELSE 'f' END AS prokind, "
 						  "provolatile, proisstrict, prosecdef, "
 						  "proleakproof, proconfig, procost, prorows, "
+						  "'-' AS prosupport, "
 						  "(SELECT lanname FROM pg_catalog.pg_language WHERE oid = prolang) AS lanname "
 						  "FROM pg_catalog.pg_proc "
 						  "WHERE oid = '%u'::pg_catalog.oid",
@@ -11579,6 +11601,7 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 						  "provolatile, proisstrict, prosecdef, "
 						  "false AS proleakproof, "
 						  " proconfig, procost, prorows, "
+						  "'-' AS prosupport, "
 						  "(SELECT lanname FROM pg_catalog.pg_language WHERE oid = prolang) AS lanname "
 						  "FROM pg_catalog.pg_proc "
 						  "WHERE oid = '%u'::pg_catalog.oid",
@@ -11593,6 +11616,7 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 						  "provolatile, proisstrict, prosecdef, "
 						  "false AS proleakproof, "
 						  "proconfig, procost, prorows, "
+						  "'-' AS prosupport, "
 						  "(SELECT lanname FROM pg_catalog.pg_language WHERE oid = prolang) AS lanname "
 						  "FROM pg_catalog.pg_proc "
 						  "WHERE oid = '%u'::pg_catalog.oid",
@@ -11607,6 +11631,7 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 						  "provolatile, proisstrict, prosecdef, "
 						  "false AS proleakproof, "
 						  "null AS proconfig, 0 AS procost, 0 AS prorows, "
+						  "'-' AS prosupport, "
 						  "(SELECT lanname FROM pg_catalog.pg_language WHERE oid = prolang) AS lanname "
 						  "FROM pg_catalog.pg_proc "
 						  "WHERE oid = '%u'::pg_catalog.oid",
@@ -11623,6 +11648,7 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 						  "provolatile, proisstrict, prosecdef, "
 						  "false AS proleakproof, "
 						  "null AS proconfig, 0 AS procost, 0 AS prorows, "
+						  "'-' AS prosupport, "
 						  "(SELECT lanname FROM pg_catalog.pg_language WHERE oid = prolang) AS lanname "
 						  "FROM pg_catalog.pg_proc "
 						  "WHERE oid = '%u'::pg_catalog.oid",
@@ -11660,6 +11686,7 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 	proconfig = PQgetvalue(res, 0, PQfnumber(res, "proconfig"));
 	procost = PQgetvalue(res, 0, PQfnumber(res, "procost"));
 	prorows = PQgetvalue(res, 0, PQfnumber(res, "prorows"));
+	prosupport = PQgetvalue(res, 0, PQfnumber(res, "prosupport"));
 
 	if (PQfnumber(res, "proparallel") != -1)
 		proparallel = PQgetvalue(res, 0, PQfnumber(res, "proparallel"));
@@ -11873,6 +11900,12 @@ dumpFunc(Archive *fout, FuncInfo *finfo)
 		strcmp(prorows, "0") != 0 && strcmp(prorows, "1000") != 0)
 		appendPQExpBuffer(q, " ROWS %s", prorows);
 
+	if (strcmp(prosupport, "-") != 0)
+	{
+		/* We rely on regprocout to provide quoting and qualification */
+		appendPQExpBuffer(q, " SUPPORT %s", prosupport);
+	}
+
 	if (proparallel != NULL && proparallel[0] != PROPARALLEL_UNSAFE)
 	{
 		if (proparallel[0] == PROPARALLEL_SAFE)
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl
index 4ff358a..d22ca73 100644
--- a/src/bin/pg_dump/t/002_pg_dump.pl
+++ b/src/bin/pg_dump/t/002_pg_dump.pl
@@ -1774,6 +1774,20 @@ my %tests = (
 		unlike => { exclude_dump_test_schema => 1, },
 	},
 
+	'CREATE FUNCTION ... SUPPORT' => {
+		create_order => 41,
+		create_sql =>
+		  'CREATE FUNCTION dump_test.func_with_support() RETURNS int LANGUAGE sql AS $$ SELECT 1 $$ SUPPORT varchar_support;',
+		regexp => qr/^
+			\QCREATE FUNCTION dump_test.func_with_support() RETURNS integer\E
+			\n\s+\QLANGUAGE sql SUPPORT varchar_support\E
+			\n\s+AS\ \$\$\Q SELECT 1 \E\$\$;
+			/xm,
+		like =>
+		  { %full_runs, %dump_test_schema_runs, section_pre_data => 1, },
+		unlike => { exclude_dump_test_schema => 1, },
+	},
+
 	'CREATE PROCEDURE dump_test.ptest1' => {
 		create_order => 41,
 		create_sql   => 'CREATE PROCEDURE dump_test.ptest1(a int)
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index b433769..e5270d2 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -201,6 +201,7 @@ extern ObjectAddress ProcedureCreate(const char *procedureName,
 				List *parameterDefaults,
 				Datum trftypes,
 				Datum proconfig,
+				Oid prosupport,
 				float4 procost,
 				float4 prorows);
 
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index adeb834..f054440 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -387,6 +387,7 @@ PG_KEYWORD("strict", STRICT_P, UNRESERVED_KEYWORD)
 PG_KEYWORD("strip", STRIP_P, UNRESERVED_KEYWORD)
 PG_KEYWORD("subscription", SUBSCRIPTION, UNRESERVED_KEYWORD)
 PG_KEYWORD("substring", SUBSTRING, COL_NAME_KEYWORD)
+PG_KEYWORD("support", SUPPORT, UNRESERVED_KEYWORD)
 PG_KEYWORD("symmetric", SYMMETRIC, RESERVED_KEYWORD)
 PG_KEYWORD("sysid", SYSID, UNRESERVED_KEYWORD)
 PG_KEYWORD("system", SYSTEM_P, UNRESERVED_KEYWORD)
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index 7bb8ca9..4db792c 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -3050,10 +3050,9 @@ DETAIL:  System catalog modifications are currently disallowed.
 -- instead create in public first, move to catalog
 CREATE TABLE new_system_table(id serial primary key, othercol text);
 ALTER TABLE new_system_table SET SCHEMA pg_catalog;
--- XXX: it's currently impossible to move relations out of pg_catalog
 ALTER TABLE new_system_table SET SCHEMA public;
-ERROR:  cannot remove dependency on schema pg_catalog because it is a system object
--- move back, will be ignored -- already there
+ALTER TABLE new_system_table SET SCHEMA pg_catalog;
+-- will be ignored -- already there:
 ALTER TABLE new_system_table SET SCHEMA pg_catalog;
 ALTER TABLE new_system_table RENAME TO old_system_table;
 CREATE INDEX old_system_table__othercol ON old_system_table (othercol);
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index a498e4e..d806430 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -1896,10 +1896,9 @@ CREATE TABLE pg_catalog.new_system_table();
 -- instead create in public first, move to catalog
 CREATE TABLE new_system_table(id serial primary key, othercol text);
 ALTER TABLE new_system_table SET SCHEMA pg_catalog;
-
--- XXX: it's currently impossible to move relations out of pg_catalog
 ALTER TABLE new_system_table SET SCHEMA public;
--- move back, will be ignored -- already there
+ALTER TABLE new_system_table SET SCHEMA pg_catalog;
+-- will be ignored -- already there:
 ALTER TABLE new_system_table SET SCHEMA pg_catalog;
 ALTER TABLE new_system_table RENAME TO old_system_table;
 CREATE INDEX old_system_table__othercol ON old_system_table (othercol);