Add construct_array_builtin, deconstruct_array_builtin

There were many calls to construct_array() and deconstruct_array() for
built-in types, for example, when dealing with system catalog columns.
These all hardcoded the type attributes necessary to pass to these
functions.

To simplify this a bit, add construct_array_builtin(),
deconstruct_array_builtin() as wrappers that centralize this hardcoded
knowledge.  This simplifies many call sites and reduces the amount of
hardcoded stuff that is spread around.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/2914356f-9e5f-8c59-2995-5997fc48bcba%40enterprisedb.com

contrib/hstore/hstore_gin.c

@@ -118,9 +118,7 @@ gin_extract_hstore_query(PG_FUNCTION_ARGS)
 					j;
 		text	   *item;
 
-		deconstruct_array(query,
+		deconstruct_array_builtin(query, TEXTOID, &key_datums, &key_nulls, &key_count);
-						  TEXTOID, -1, false, TYPALIGN_INT,
-						  &key_datums, &key_nulls, &key_count);
 
 		entries = (Datum *) palloc(sizeof(Datum) * key_count);
 

contrib/hstore/hstore_gist.c

@@ -560,9 +560,7 @@ ghstore_consistent(PG_FUNCTION_ARGS)
 		int			key_count;
 		int			i;
 
-		deconstruct_array(query,
+		deconstruct_array_builtin(query, TEXTOID, &key_datums, &key_nulls, &key_count);
-						  TEXTOID, -1, false, TYPALIGN_INT,
-						  &key_datums, &key_nulls, &key_count);
 
 		for (i = 0; res && i < key_count; ++i)
 		{
@@ -583,9 +581,7 @@ ghstore_consistent(PG_FUNCTION_ARGS)
 		int			key_count;
 		int			i;
 
-		deconstruct_array(query,
+		deconstruct_array_builtin(query, TEXTOID, &key_datums, &key_nulls, &key_count);
-						  TEXTOID, -1, false, TYPALIGN_INT,
-						  &key_datums, &key_nulls, &key_count);
 
 		res = false;
 

contrib/hstore/hstore_io.c

@@ -567,9 +567,7 @@ hstore_from_arrays(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
 				 errmsg("wrong number of array subscripts")));
 
-	deconstruct_array(key_array,
+	deconstruct_array_builtin(key_array, TEXTOID, &key_datums, &key_nulls, &key_count);
-					  TEXTOID, -1, false, TYPALIGN_INT,
-					  &key_datums, &key_nulls, &key_count);
 
 	/* see discussion in hstoreArrayToPairs() */
 	if (key_count > MaxAllocSize / sizeof(Pairs))
@@ -606,9 +604,7 @@ hstore_from_arrays(PG_FUNCTION_ARGS)
 					(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
 					 errmsg("arrays must have same bounds")));
 
-		deconstruct_array(value_array,
+		deconstruct_array_builtin(value_array, TEXTOID, &value_datums, &value_nulls, &value_count);
-						  TEXTOID, -1, false, TYPALIGN_INT,
-						  &value_datums, &value_nulls, &value_count);
 
 		Assert(key_count == value_count);
 	}
@@ -696,9 +692,7 @@ hstore_from_array(PG_FUNCTION_ARGS)
 					 errmsg("wrong number of array subscripts")));
 	}
 
-	deconstruct_array(in_array,
+	deconstruct_array_builtin(in_array, TEXTOID, &in_datums, &in_nulls, &in_count);
-					  TEXTOID, -1, false, TYPALIGN_INT,
-					  &in_datums, &in_nulls, &in_count);
 
 	count = in_count / 2;
 

contrib/hstore/hstore_op.c

@@ -80,9 +80,7 @@ hstoreArrayToPairs(ArrayType *a, int *npairs)
 	int			i,
 				j;
 
-	deconstruct_array(a,
+	deconstruct_array_builtin(a, TEXTOID, &key_datums, &key_nulls, &key_count);
-					  TEXTOID, -1, false, TYPALIGN_INT,
-					  &key_datums, &key_nulls, &key_count);
 
 	if (key_count == 0)
 	{
@@ -582,9 +580,7 @@ hstore_slice_to_array(PG_FUNCTION_ARGS)
 	int			key_count;
 	int			i;
 
-	deconstruct_array(key_array,
+	deconstruct_array_builtin(key_array, TEXTOID, &key_datums, &key_nulls, &key_count);
-					  TEXTOID, -1, false, TYPALIGN_INT,
-					  &key_datums, &key_nulls, &key_count);
 
 	if (key_count == 0)
 	{
@@ -719,8 +715,7 @@ hstore_akeys(PG_FUNCTION_ARGS)
 		d[i] = PointerGetDatum(t);
 	}
 
-	a = construct_array(d, count,
+	a = construct_array_builtin(d, count, TEXTOID);
-						TEXTOID, -1, false, TYPALIGN_INT);
 
 	PG_RETURN_POINTER(a);
 }

contrib/pageinspect/btreefuncs.c

@@ -425,11 +425,7 @@ bt_page_print_tuples(struct user_args *uargs)
 		tids_datum = (Datum *) palloc(nposting * sizeof(Datum));
 		for (int i = 0; i < nposting; i++)
 			tids_datum[i] = ItemPointerGetDatum(&tids[i]);
-		values[j++] = PointerGetDatum(construct_array(tids_datum,
+		values[j++] = PointerGetDatum(construct_array_builtin(tids_datum, nposting, TIDOID));
-													  nposting,
-													  TIDOID,
-													  sizeof(ItemPointerData),
-													  false, TYPALIGN_SHORT));
 		pfree(tids_datum);
 	}
 	else

contrib/pageinspect/ginfuncs.c

@@ -166,9 +166,7 @@ gin_page_opaque_info(PG_FUNCTION_ARGS)
 
 	values[0] = Int64GetDatum(opaq->rightlink);
 	values[1] = Int32GetDatum(opaq->maxoff);
-	values[2] = PointerGetDatum(construct_array(flags, nflags,
+	values[2] = PointerGetDatum(construct_array_builtin(flags, nflags, TEXTOID));
-												TEXTOID,
-												-1, false, TYPALIGN_INT));
 
 	/* Build and return the result tuple. */
 	resultTuple = heap_form_tuple(tupdesc, values, nulls);
@@ -273,11 +271,7 @@ gin_leafpage_items(PG_FUNCTION_ARGS)
 		tids_datum = (Datum *) palloc(ndecoded * sizeof(Datum));
 		for (i = 0; i < ndecoded; i++)
 			tids_datum[i] = ItemPointerGetDatum(&tids[i]);
-		values[2] = PointerGetDatum(construct_array(tids_datum,
+		values[2] = PointerGetDatum(construct_array_builtin(tids_datum, ndecoded, TIDOID));
-													ndecoded,
-													TIDOID,
-													sizeof(ItemPointerData),
-													false, TYPALIGN_SHORT));
 		pfree(tids_datum);
 		pfree(tids);
 

contrib/pageinspect/gistfuncs.c

@@ -104,9 +104,7 @@ gist_page_opaque_info(PG_FUNCTION_ARGS)
 	values[0] = LSNGetDatum(PageGetLSN(page));
 	values[1] = LSNGetDatum(GistPageGetNSN(page));
 	values[2] = Int64GetDatum(opaq->rightlink);
-	values[3] = PointerGetDatum(construct_array(flags, nflags,
+	values[3] = PointerGetDatum(construct_array_builtin(flags, nflags, TEXTOID));
-												TEXTOID,
-												-1, false, TYPALIGN_INT));
 
 	/* Build and return the result tuple. */
 	resultTuple = heap_form_tuple(tupdesc, values, nulls);

contrib/pageinspect/hashfuncs.c

@@ -564,21 +564,11 @@ hash_metapage_info(PG_FUNCTION_ARGS)
 
 	for (i = 0; i < HASH_MAX_SPLITPOINTS; i++)
 		spares[i] = Int64GetDatum((int64) metad->hashm_spares[i]);
-	values[j++] = PointerGetDatum(construct_array(spares,
+	values[j++] = PointerGetDatum(construct_array_builtin(spares, HASH_MAX_SPLITPOINTS, INT8OID));
-												  HASH_MAX_SPLITPOINTS,
-												  INT8OID,
-												  sizeof(int64),
-												  FLOAT8PASSBYVAL,
-												  TYPALIGN_DOUBLE));
 
 	for (i = 0; i < HASH_MAX_BITMAPS; i++)
 		mapp[i] = Int64GetDatum((int64) metad->hashm_mapp[i]);
-	values[j++] = PointerGetDatum(construct_array(mapp,
+	values[j++] = PointerGetDatum(construct_array_builtin(mapp, HASH_MAX_BITMAPS, INT8OID));
-												  HASH_MAX_BITMAPS,
-												  INT8OID,
-												  sizeof(int64),
-												  FLOAT8PASSBYVAL,
-												  TYPALIGN_DOUBLE));
 
 	tuple = heap_form_tuple(tupleDesc, values, nulls);
 

contrib/pageinspect/heapfuncs.c

@@ -590,7 +590,7 @@ heap_tuple_infomask_flags(PG_FUNCTION_ARGS)
 
 	/* build value */
 	Assert(cnt <= bitcnt);
-	a = construct_array(flags, cnt, TEXTOID, -1, false, TYPALIGN_INT);
+	a = construct_array_builtin(flags, cnt, TEXTOID);
 	values[0] = PointerGetDatum(a);
 
 	/*
@@ -612,7 +612,7 @@ heap_tuple_infomask_flags(PG_FUNCTION_ARGS)
 	if (cnt == 0)
 		a = construct_empty_array(TEXTOID);
 	else
-		a = construct_array(flags, cnt, TEXTOID, -1, false, TYPALIGN_INT);
+		a = construct_array_builtin(flags, cnt, TEXTOID);
 	pfree(flags);
 	values[1] = PointerGetDatum(a);
 

contrib/pg_trgm/trgm_op.c

@@ -977,12 +977,7 @@ show_trgm(PG_FUNCTION_ARGS)
 		d[i] = PointerGetDatum(item);
 	}
 
-	a = construct_array(d,
+	a = construct_array_builtin(d, ARRNELEM(trg), TEXTOID);
-						ARRNELEM(trg),
-						TEXTOID,
-						-1,
-						false,
-						TYPALIGN_INT);
 
 	for (i = 0; i < ARRNELEM(trg); i++)
 		pfree(DatumGetPointer(d[i]));

contrib/pgcrypto/pgp-pgsql.c

@@ -774,13 +774,8 @@ parse_key_value_arrays(ArrayType *key_array, ArrayType *val_array,
 	if (nkdims == 0)
 		return 0;
 
-	deconstruct_array(key_array,
+	deconstruct_array_builtin(key_array, TEXTOID, &key_datums, &key_nulls, &key_count);
-					  TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(val_array, TEXTOID, &val_datums, &val_nulls, &val_count);
-					  &key_datums, &key_nulls, &key_count);
-
-	deconstruct_array(val_array,
-					  TEXTOID, -1, false, TYPALIGN_INT,
-					  &val_datums, &val_nulls, &val_count);
 
 	if (key_count != val_count)
 		ereport(ERROR,

src/backend/access/common/reloptions.c

@@ -1177,8 +1177,7 @@ transformRelOptions(Datum oldOptions, List *defList, const char *namspace,
 		int			noldoptions;
 		int			i;
 
-		deconstruct_array(array, TEXTOID, -1, false, TYPALIGN_INT,
+		deconstruct_array_builtin(array, TEXTOID, &oldoptions, NULL, &noldoptions);
-						  &oldoptions, NULL, &noldoptions);
 
 		for (i = 0; i < noldoptions; i++)
 		{
@@ -1345,8 +1344,7 @@ untransformRelOptions(Datum options)
 
 	array = DatumGetArrayTypeP(options);
 
-	deconstruct_array(array, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(array, TEXTOID, &optiondatums, NULL, &noptions);
-					  &optiondatums, NULL, &noptions);
 
 	for (i = 0; i < noptions; i++)
 	{
@@ -1436,8 +1434,7 @@ parseRelOptionsInternal(Datum options, bool validate,
 	int			noptions;
 	int			i;
 
-	deconstruct_array(array, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(array, TEXTOID, &optiondatums, NULL, &noptions);
-					  &optiondatums, NULL, &noptions);
 
 	for (i = 0; i < noptions; i++)
 	{

src/backend/catalog/objectaddress.c

@@ -2099,8 +2099,7 @@ textarray_to_strvaluelist(ArrayType *arr)
 	List	   *list = NIL;
 	int			i;
 
-	deconstruct_array(arr, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(arr, TEXTOID, &elems, &nulls, &nelems);
-					  &elems, &nulls, &nelems);
 
 	for (i = 0; i < nelems; i++)
 	{
@@ -2156,8 +2155,7 @@ pg_get_object_address(PG_FUNCTION_ARGS)
 		bool	   *nulls;
 		int			nelems;
 
-		deconstruct_array(namearr, TEXTOID, -1, false, TYPALIGN_INT,
+		deconstruct_array_builtin(namearr, TEXTOID, &elems, &nulls, &nelems);
-						  &elems, &nulls, &nelems);
 		if (nelems != 1)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
@@ -2174,8 +2172,7 @@ pg_get_object_address(PG_FUNCTION_ARGS)
 		bool	   *nulls;
 		int			nelems;
 
-		deconstruct_array(namearr, TEXTOID, -1, false, TYPALIGN_INT,
+		deconstruct_array_builtin(namearr, TEXTOID, &elems, &nulls, &nelems);
-						  &elems, &nulls, &nelems);
 		if (nelems != 1)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
@@ -2213,8 +2210,7 @@ pg_get_object_address(PG_FUNCTION_ARGS)
 		int			nelems;
 		int			i;
 
-		deconstruct_array(argsarr, TEXTOID, -1, false, TYPALIGN_INT,
+		deconstruct_array_builtin(argsarr, TEXTOID, &elems, &nulls, &nelems);
-						  &elems, &nulls, &nelems);
 
 		args = NIL;
 		for (i = 0; i < nelems; i++)

src/backend/catalog/pg_constraint.c

@@ -112,8 +112,7 @@ CreateConstraintEntry(const char *constraintName,
 		conkey = (Datum *) palloc(constraintNKeys * sizeof(Datum));
 		for (i = 0; i < constraintNKeys; i++)
 			conkey[i] = Int16GetDatum(constraintKey[i]);
-		conkeyArray = construct_array(conkey, constraintNKeys,
+		conkeyArray = construct_array_builtin(conkey, constraintNKeys, INT2OID);
-									  INT2OID, 2, true, TYPALIGN_SHORT);
 	}
 	else
 		conkeyArray = NULL;
@@ -125,27 +124,22 @@ CreateConstraintEntry(const char *constraintName,
 		fkdatums = (Datum *) palloc(foreignNKeys * sizeof(Datum));
 		for (i = 0; i < foreignNKeys; i++)
 			fkdatums[i] = Int16GetDatum(foreignKey[i]);
-		confkeyArray = construct_array(fkdatums, foreignNKeys,
+		confkeyArray = construct_array_builtin(fkdatums, foreignNKeys, INT2OID);
-									   INT2OID, 2, true, TYPALIGN_SHORT);
 		for (i = 0; i < foreignNKeys; i++)
 			fkdatums[i] = ObjectIdGetDatum(pfEqOp[i]);
-		conpfeqopArray = construct_array(fkdatums, foreignNKeys,
+		conpfeqopArray = construct_array_builtin(fkdatums, foreignNKeys, OIDOID);
-										 OIDOID, sizeof(Oid), true, TYPALIGN_INT);
 		for (i = 0; i < foreignNKeys; i++)
 			fkdatums[i] = ObjectIdGetDatum(ppEqOp[i]);
-		conppeqopArray = construct_array(fkdatums, foreignNKeys,
+		conppeqopArray = construct_array_builtin(fkdatums, foreignNKeys, OIDOID);
-										 OIDOID, sizeof(Oid), true, TYPALIGN_INT);
 		for (i = 0; i < foreignNKeys; i++)
 			fkdatums[i] = ObjectIdGetDatum(ffEqOp[i]);
-		conffeqopArray = construct_array(fkdatums, foreignNKeys,
+		conffeqopArray = construct_array_builtin(fkdatums, foreignNKeys, OIDOID);
-										 OIDOID, sizeof(Oid), true, TYPALIGN_INT);
 
 		if (numFkDeleteSetCols > 0)
 		{
 			for (i = 0; i < numFkDeleteSetCols; i++)
 				fkdatums[i] = Int16GetDatum(fkDeleteSetCols[i]);
-			confdelsetcolsArray = construct_array(fkdatums, numFkDeleteSetCols,
+			confdelsetcolsArray = construct_array_builtin(fkdatums, numFkDeleteSetCols, INT2OID);
-												  INT2OID, 2, true, TYPALIGN_SHORT);
 		}
 		else
 			confdelsetcolsArray = NULL;
@@ -166,8 +160,7 @@ CreateConstraintEntry(const char *constraintName,
 		opdatums = (Datum *) palloc(constraintNKeys * sizeof(Datum));
 		for (i = 0; i < constraintNKeys; i++)
 			opdatums[i] = ObjectIdGetDatum(exclOp[i]);
-		conexclopArray = construct_array(opdatums, constraintNKeys,
+		conexclopArray = construct_array_builtin(opdatums, constraintNKeys, OIDOID);
-										 OIDOID, sizeof(Oid), true, TYPALIGN_INT);
 	}
 	else
 		conexclopArray = NULL;

src/backend/catalog/pg_proc.c

@@ -1193,10 +1193,7 @@ oid_array_to_list(Datum datum)
 	int			i;
 	List	   *result = NIL;
 
-	deconstruct_array(array,
+	deconstruct_array_builtin(array, OIDOID, &values, NULL, &nelems);
-					  OIDOID,
-					  sizeof(Oid), true, TYPALIGN_INT,
-					  &values, NULL, &nelems);
 	for (i = 0; i < nelems; i++)
 		result = lappend_oid(result, values[i]);
 	return result;

src/backend/catalog/pg_subscription.c

@@ -260,9 +260,7 @@ textarray_to_stringlist(ArrayType *textarray)
 				i;
 	List	   *res = NIL;
 
-	deconstruct_array(textarray,
+	deconstruct_array_builtin(textarray, TEXTOID, &elems, NULL, &nelems);
-					  TEXTOID, -1, false, TYPALIGN_INT,
-					  &elems, NULL, &nelems);
 
 	if (nelems == 0)
 		return NIL;

src/backend/commands/analyze.c

@@ -1688,10 +1688,7 @@ update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
 
 				for (n = 0; n < nnum; n++)
 					numdatums[n] = Float4GetDatum(stats->stanumbers[k][n]);
-				/* XXX knows more than it should about type float4: */
+				arry = construct_array_builtin(numdatums, nnum, FLOAT4OID);
-				arry = construct_array(numdatums, nnum,
-									   FLOAT4OID,
-									   sizeof(float4), true, TYPALIGN_INT);
 				values[i++] = PointerGetDatum(arry);	/* stanumbersN */
 			}
 			else

src/backend/commands/event_trigger.c

@@ -351,8 +351,7 @@ filter_list_to_array(List *filterlist)
 		pfree(result);
 	}
 
-	return PointerGetDatum(construct_array(data, l, TEXTOID,
+	return PointerGetDatum(construct_array_builtin(data, l, TEXTOID));
-										   -1, false, TYPALIGN_INT));
 }
 
 /*

src/backend/commands/extension.c

@@ -2251,9 +2251,7 @@ convert_requires_to_datum(List *requires)
 		datums[ndatums++] =
 			DirectFunctionCall1(namein, CStringGetDatum(curreq));
 	}
-	a = construct_array(datums, ndatums,
+	a = construct_array_builtin(datums, ndatums, NAMEOID);
-						NAMEOID,
-						NAMEDATALEN, false, TYPALIGN_CHAR);
 	return PointerGetDatum(a);
 }
 
@@ -2433,9 +2431,7 @@ pg_extension_config_dump(PG_FUNCTION_ARGS)
 		arrayLength = 0;
 		arrayIndex = 1;
 
-		a = construct_array(&elementDatum, 1,
+		a = construct_array_builtin(&elementDatum, 1, OIDOID);
-							OIDOID,
-							sizeof(Oid), true, TYPALIGN_INT);
 	}
 	else
 	{
@@ -2486,9 +2482,7 @@ pg_extension_config_dump(PG_FUNCTION_ARGS)
 		if (arrayLength != 0)
 			elog(ERROR, "extconfig and extcondition arrays do not match");
 
-		a = construct_array(&elementDatum, 1,
+		a = construct_array_builtin(&elementDatum, 1, TEXTOID);
-							TEXTOID,
-							-1, false, TYPALIGN_INT);
 	}
 	else
 	{
@@ -2630,14 +2624,12 @@ extension_config_remove(Oid extensionoid, Oid tableoid)
 		int			i;
 
 		/* We already checked there are no nulls */
-		deconstruct_array(a, OIDOID, sizeof(Oid), true, TYPALIGN_INT,
+		deconstruct_array_builtin(a, OIDOID, &dvalues, NULL, &nelems);
-						  &dvalues, NULL, &nelems);
 
 		for (i = arrayIndex; i < arrayLength - 1; i++)
 			dvalues[i] = dvalues[i + 1];
 
-		a = construct_array(dvalues, arrayLength - 1,
+		a = construct_array_builtin(dvalues, arrayLength - 1, OIDOID);
-							OIDOID, sizeof(Oid), true, TYPALIGN_INT);
 
 		repl_val[Anum_pg_extension_extconfig - 1] = PointerGetDatum(a);
 	}
@@ -2676,14 +2668,12 @@ extension_config_remove(Oid extensionoid, Oid tableoid)
 		int			i;
 
 		/* We already checked there are no nulls */
-		deconstruct_array(a, TEXTOID, -1, false, TYPALIGN_INT,
+		deconstruct_array_builtin(a, TEXTOID, &dvalues, NULL, &nelems);
-						  &dvalues, NULL, &nelems);
 
 		for (i = arrayIndex; i < arrayLength - 1; i++)
 			dvalues[i] = dvalues[i + 1];
 
-		a = construct_array(dvalues, arrayLength - 1,
+		a = construct_array_builtin(dvalues, arrayLength - 1, TEXTOID);
-							TEXTOID, -1, false, TYPALIGN_INT);
 
 		repl_val[Anum_pg_extension_extcondition - 1] = PointerGetDatum(a);
 	}

src/backend/commands/functioncmds.c

@@ -468,10 +468,8 @@ interpret_function_parameter_list(ParseState *pstate,
 
 	if (outCount > 0 || varCount > 0)
 	{
-		*allParameterTypes = construct_array(allTypes, parameterCount, OIDOID,
+		*allParameterTypes = construct_array_builtin(allTypes, parameterCount, OIDOID);
-											 sizeof(Oid), true, TYPALIGN_INT);
+		*parameterModes = construct_array_builtin(paramModes, parameterCount, CHAROID);
-		*parameterModes = construct_array(paramModes, parameterCount, CHAROID,
-										  1, true, TYPALIGN_CHAR);
 		if (outCount > 1)
 			*requiredResultType = RECORDOID;
 		/* otherwise we set requiredResultType correctly above */
@@ -489,8 +487,7 @@ interpret_function_parameter_list(ParseState *pstate,
 			if (paramNames[i] == PointerGetDatum(NULL))
 				paramNames[i] = CStringGetTextDatum("");
 		}
-		*parameterNames = construct_array(paramNames, parameterCount, TEXTOID,
+		*parameterNames = construct_array_builtin(paramNames, parameterCount, TEXTOID);
-										  -1, false, TYPALIGN_INT);
 	}
 	else
 		*parameterNames = NULL;
@@ -1222,8 +1219,7 @@ CreateFunction(ParseState *pstate, CreateFunctionStmt *stmt)
 		i = 0;
 		foreach(lc, trftypes_list)
 			arr[i++] = ObjectIdGetDatum(lfirst_oid(lc));
-		trftypes = construct_array(arr, list_length(trftypes_list),
+		trftypes = construct_array_builtin(arr, list_length(trftypes_list), OIDOID);
-								   OIDOID, sizeof(Oid), true, TYPALIGN_INT);
 	}
 	else
 	{

src/backend/commands/policy.c

@@ -500,8 +500,7 @@ RemoveRoleFromObjectPolicy(Oid roleid, Oid classid, Oid policy_id)
 		memset(isnull, 0, sizeof(isnull));
 
 		/* This is the array for the new tuple */
-		role_ids = construct_array(role_oids, num_roles, OIDOID,
+		role_ids = construct_array_builtin(role_oids, num_roles, OIDOID);
-								   sizeof(Oid), true, TYPALIGN_INT);
 
 		replaces[Anum_pg_policy_polroles - 1] = true;
 		values[Anum_pg_policy_polroles - 1] = PointerGetDatum(role_ids);
@@ -617,8 +616,7 @@ CreatePolicy(CreatePolicyStmt *stmt)
 
 	/* Collect role ids */
 	role_oids = policy_role_list_to_array(stmt->roles, &nitems);
-	role_ids = construct_array(role_oids, nitems, OIDOID,
+	role_ids = construct_array_builtin(role_oids, nitems, OIDOID);
-							   sizeof(Oid), true, TYPALIGN_INT);
 
 	/* Parse the supplied clause */
 	qual_pstate = make_parsestate(NULL);
@@ -801,8 +799,7 @@ AlterPolicy(AlterPolicyStmt *stmt)
 	if (stmt->roles != NULL)
 	{
 		role_oids = policy_role_list_to_array(stmt->roles, &nitems);
-		role_ids = construct_array(role_oids, nitems, OIDOID,
+		role_ids = construct_array_builtin(role_oids, nitems, OIDOID);
-								   sizeof(Oid), true, TYPALIGN_INT);
 	}
 
 	/* Get id of table.  Also handles permissions checks. */

src/backend/commands/prepare.c

@@ -722,8 +722,6 @@ build_regtype_array(Oid *param_types, int num_params)
 	for (i = 0; i < num_params; i++)
 		tmp_ary[i] = ObjectIdGetDatum(param_types[i]);
 
-	/* XXX: this hardcodes assumptions about the regtype type */
+	result = construct_array_builtin(tmp_ary, num_params, REGTYPEOID);
-	result = construct_array(tmp_ary, num_params, REGTYPEOID,
-							 4, true, TYPALIGN_INT);
 	return PointerGetDatum(result);
 }

src/backend/commands/statscmds.c

@@ -467,7 +467,7 @@ CreateStatistics(CreateStatsStmt *stmt)
 	if (build_expressions)
 		types[ntypes++] = CharGetDatum(STATS_EXT_EXPRESSIONS);
 	Assert(ntypes > 0 && ntypes <= lengthof(types));
-	stxkind = construct_array(types, ntypes, CHAROID, 1, true, TYPALIGN_CHAR);
+	stxkind = construct_array_builtin(types, ntypes, CHAROID);
 
 	/* convert the expressions (if any) to a text datum */
 	if (stxexprs != NIL)

src/backend/commands/subscriptioncmds.c

@@ -494,8 +494,7 @@ publicationListToArray(List *publist)
 
 	MemoryContextSwitchTo(oldcxt);
 
-	arr = construct_array(datums, list_length(publist),
+	arr = construct_array_builtin(datums, list_length(publist), TEXTOID);
-						  TEXTOID, -1, false, TYPALIGN_INT);
 
 	MemoryContextDelete(memcxt);
 

src/backend/commands/typecmds.c

@@ -1893,12 +1893,9 @@ makeMultirangeConstructors(const char *name, Oid namespace,
 	/* n-arg constructor - vararg */
 	argtypes = buildoidvector(&rangeArrayOid, 1);
 	allParamTypes = ObjectIdGetDatum(rangeArrayOid);
-	allParameterTypes = construct_array(&allParamTypes,
+	allParameterTypes = construct_array_builtin(&allParamTypes, 1, OIDOID);
-										1, OIDOID,
-										sizeof(Oid), true, TYPALIGN_INT);
 	paramModes = CharGetDatum(FUNC_PARAM_VARIADIC);
-	parameterModes = construct_array(&paramModes, 1, CHAROID,
+	parameterModes = construct_array_builtin(&paramModes, 1, CHAROID);
-									 1, true, TYPALIGN_CHAR);
 	myself = ProcedureCreate(name,	/* name: same as multirange type */
 							 namespace,
 							 false, /* replace */

src/backend/executor/nodeTidscan.c

@@ -206,9 +206,7 @@ TidListEval(TidScanState *tidstate)
 			if (isNull)
 				continue;
 			itemarray = DatumGetArrayTypeP(arraydatum);
-			deconstruct_array(itemarray,
+			deconstruct_array_builtin(itemarray, TIDOID, &ipdatums, &ipnulls, &ndatums);
-							  TIDOID, sizeof(ItemPointerData), false, TYPALIGN_SHORT,
-							  &ipdatums, &ipnulls, &ndatums);
 			if (numTids + ndatums > numAllocTids)
 			{
 				numAllocTids = numTids + ndatums;

src/backend/parser/parse_type.c

@@ -411,9 +411,7 @@ typenameTypeMod(ParseState *pstate, const TypeName *typeName, Type typ)
 		datums[n++] = CStringGetDatum(cstr);
 	}
 
-	/* hardwired knowledge about cstring's representation details here */
+	arrtypmod = construct_array_builtin(datums, n, CSTRINGOID);
-	arrtypmod = construct_array(datums, n, CSTRINGOID,
-								-2, false, TYPALIGN_CHAR);
 
 	/* arrange to report location if type's typmodin function fails */
 	setup_parser_errposition_callback(&pcbstate, pstate, typeName->location);

src/backend/parser/parse_utilcmd.c

@@ -1642,9 +1642,7 @@ generateClonedIndexStmt(RangeVar *heapRel, Relation source_idx,
 					elog(ERROR, "null conexclop for constraint %u",
 						 constraintId);
 
-				deconstruct_array(DatumGetArrayTypeP(datum),
+				deconstruct_array_builtin(DatumGetArrayTypeP(datum), OIDOID, &elems, NULL, &nElems);
-								  OIDOID, sizeof(Oid), true, TYPALIGN_INT,
-								  &elems, NULL, &nElems);
 
 				for (i = 0; i < nElems; i++)
 				{

src/backend/replication/logical/logicalfuncs.c

@@ -172,8 +172,7 @@ pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool bin
 
 		Assert(ARR_ELEMTYPE(arr) == TEXTOID);
 
-		deconstruct_array(arr, TEXTOID, -1, false, TYPALIGN_INT,
+		deconstruct_array_builtin(arr, TEXTOID, &datum_opts, NULL, &nelems);
-						  &datum_opts, NULL, &nelems);
 
 		if (nelems % 2 != 0)
 			ereport(ERROR,

src/backend/statistics/extended_stats.c

@@ -2345,10 +2345,7 @@ serialize_expr_stats(AnlExprData *exprdata, int nexprs)
 
 				for (n = 0; n < nnum; n++)
 					numdatums[n] = Float4GetDatum(stats->stanumbers[k][n]);
-				/* XXX knows more than it should about type float4: */
+				arry = construct_array_builtin(numdatums, nnum, FLOAT4OID);
-				arry = construct_array(numdatums, nnum,
-									   FLOAT4OID,
-									   sizeof(float4), true, TYPALIGN_INT);
 				values[i++] = PointerGetDatum(arry);	/* stanumbersN */
 			}
 			else

src/backend/tsearch/dict.c

@@ -68,12 +68,7 @@ ts_lexize(PG_FUNCTION_ARGS)
 		ptr++;
 	}
 
-	a = construct_array(da,
+	a = construct_array_builtin(da, ptr - res, TEXTOID);
-						ptr - res,
-						TEXTOID,
-						-1,
-						false,
-						TYPALIGN_INT);
 
 	ptr = res;
 	while (ptr->lexeme)

src/backend/utils/adt/arrayfuncs.c

@@ -3330,6 +3330,92 @@ construct_array(Datum *elems, int nelems,
 							  elmtype, elmlen, elmbyval, elmalign);
 }
 
+/*
+ * Like construct_array(), where elmtype must be a built-in type, and
+ * elmlen/elmbyval/elmalign is looked up from hardcoded data.  This is often
+ * useful when manipulating arrays from/for system catalogs.
+ */
+ArrayType *
+construct_array_builtin(Datum *elems, int nelems, Oid elmtype)
+{
+	int			elmlen;
+	bool		elmbyval;
+	char		elmalign;
+
+	switch (elmtype)
+	{
+		case CHAROID:
+			elmlen = 1;
+			elmbyval = true;
+			elmalign = TYPALIGN_CHAR;
+			break;
+
+		case CSTRINGOID:
+			elmlen = -2;
+			elmbyval = false;
+			elmalign = TYPALIGN_CHAR;
+			break;
+
+		case FLOAT4OID:
+			elmlen = sizeof(float4);
+			elmbyval = true;
+			elmalign = TYPALIGN_INT;
+			break;
+
+		case INT2OID:
+			elmlen = sizeof(int16);
+			elmbyval = true;
+			elmalign = TYPALIGN_SHORT;
+			break;
+
+		case INT4OID:
+			elmlen = sizeof(int32);
+			elmbyval = true;
+			elmalign = TYPALIGN_INT;
+			break;
+
+		case INT8OID:
+			elmlen = sizeof(int64);
+			elmbyval = FLOAT8PASSBYVAL;
+			elmalign = TYPALIGN_DOUBLE;
+			break;
+
+		case NAMEOID:
+			elmlen = NAMEDATALEN;
+			elmbyval = false;
+			elmalign = TYPALIGN_CHAR;
+			break;
+
+		case OIDOID:
+		case REGTYPEOID:
+			elmlen = sizeof(Oid);
+			elmbyval = true;
+			elmalign = TYPALIGN_INT;
+			break;
+
+		case TEXTOID:
+			elmlen = -1;
+			elmbyval = false;
+			elmalign = TYPALIGN_INT;
+			break;
+
+		case TIDOID:
+			elmlen = sizeof(ItemPointerData);
+			elmbyval = false;
+			elmalign = TYPALIGN_SHORT;
+			break;
+
+		default:
+			elog(ERROR, "type %u not supported by construct_array_builtin()", elmtype);
+			/* keep compiler quiet */
+			elmlen = 0;
+			elmbyval = false;
+			elmalign = 0;
+	}
+
+	return construct_array(elems, nelems, elmtype, elmlen, elmbyval, elmalign);
+}
+
 /*
  * construct_md_array	--- simple method for constructing an array object
  *							with arbitrary dimensions and possible NULLs
@@ -3483,9 +3569,9 @@ construct_empty_expanded_array(Oid element_type,
  * be pointers into the array object.
  *
  * NOTE: it would be cleaner to look up the elmlen/elmbval/elmalign info
- * from the system catalogs, given the elmtype.  However, in most current
+ * from the system catalogs, given the elmtype.  However, the caller is
- * uses the type is hard-wired into the caller and so we can save a lookup
+ * in a better position to cache this info across multiple uses, or even
- * cycle by hard-wiring the type info as well.
+ * to hard-wire values if the element type is hard-wired.
  */
 void
 deconstruct_array(ArrayType *array,
@@ -3548,6 +3634,75 @@ deconstruct_array(ArrayType *array,
 	}
 }
 
+/*
+ * Like deconstruct_array(), where elmtype must be a built-in type, and
+ * elmlen/elmbyval/elmalign is looked up from hardcoded data.  This is often
+ * useful when manipulating arrays from/for system catalogs.
+ */
+void
+deconstruct_array_builtin(ArrayType *array,
+						  Oid elmtype,
+						  Datum **elemsp, bool **nullsp, int *nelemsp)
+{
+	int			elmlen;
+	bool		elmbyval;
+	char		elmalign;
+
+	switch (elmtype)
+	{
+		case CHAROID:
+			elmlen = 1;
+			elmbyval = true;
+			elmalign = TYPALIGN_CHAR;
+			break;
+
+		case CSTRINGOID:
+			elmlen = -2;
+			elmbyval = false;
+			elmalign = TYPALIGN_CHAR;
+			break;
+
+		case FLOAT8OID:
+			elmlen = sizeof(float8);
+			elmbyval = FLOAT8PASSBYVAL;
+			elmalign = TYPALIGN_DOUBLE;
+			break;
+
+		case INT2OID:
+			elmlen = sizeof(int16);
+			elmbyval = true;
+			elmalign = TYPALIGN_SHORT;
+			break;
+
+		case OIDOID:
+			elmlen = sizeof(Oid);
+			elmbyval = true;
+			elmalign = TYPALIGN_INT;
+			break;
+
+		case TEXTOID:
+			elmlen = -1;
+			elmbyval = false;
+			elmalign = TYPALIGN_INT;
+			break;
+
+		case TIDOID:
+			elmlen = sizeof(ItemPointerData);
+			elmbyval = false;
+			elmalign = TYPALIGN_SHORT;
+			break;
+
+		default:
+			elog(ERROR, "type %u not supported by deconstruct_array_builtin()", elmtype);
+			/* keep compiler quiet */
+			elmlen = 0;
+			elmbyval = false;
+			elmalign = 0;
+	}
+
+	deconstruct_array(array, elmtype, elmlen, elmbyval, elmalign, elemsp, nullsp, nelemsp);
+}
+
 /*
  * array_contains_nulls --- detect whether an array has any null elements
  *

src/backend/utils/adt/arrayutils.c

@@ -249,10 +249,7 @@ ArrayGetIntegerTypmods(ArrayType *arr, int *n)
 				(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
 				 errmsg("typmod array must not contain nulls")));
 
-	/* hardwired knowledge about cstring's representation details here */
+	deconstruct_array_builtin(arr, CSTRINGOID, &elem_values, NULL, n);
-	deconstruct_array(arr, CSTRINGOID,
-					  -2, false, TYPALIGN_CHAR,
-					  &elem_values, NULL, n);
 
 	result = (int32 *) palloc(*n * sizeof(int32));
 

src/backend/utils/adt/hbafuncs.c

@@ -151,7 +151,7 @@ get_hba_options(HbaLine *hba)
 	Assert(noptions <= MAX_HBA_OPTIONS);
 
 	if (noptions > 0)
-		return construct_array(options, noptions, TEXTOID, -1, false, TYPALIGN_INT);
+		return construct_array_builtin(options, noptions, TEXTOID);
 	else
 		return NULL;
 }

src/backend/utils/adt/json.c

@@ -1450,9 +1450,7 @@ json_object(PG_FUNCTION_ARGS)
 					 errmsg("wrong number of array subscripts")));
 	}
 
-	deconstruct_array(in_array,
+	deconstruct_array_builtin(in_array, TEXTOID, &in_datums, &in_nulls, &in_count);
-					  TEXTOID, -1, false, TYPALIGN_INT,
-					  &in_datums, &in_nulls, &in_count);
 
 	count = in_count / 2;
 
@@ -1526,13 +1524,8 @@ json_object_two_arg(PG_FUNCTION_ARGS)
 	if (nkdims == 0)
 		PG_RETURN_DATUM(CStringGetTextDatum("{}"));
 
-	deconstruct_array(key_array,
+	deconstruct_array_builtin(key_array, TEXTOID, &key_datums, &key_nulls, &key_count);
-					  TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(val_array, TEXTOID, &val_datums, &val_nulls, &val_count);
-					  &key_datums, &key_nulls, &key_count);
-
-	deconstruct_array(val_array,
-					  TEXTOID, -1, false, TYPALIGN_INT,
-					  &val_datums, &val_nulls, &val_count);
 
 	if (key_count != val_count)
 		ereport(ERROR,

src/backend/utils/adt/jsonb.c

@@ -1378,9 +1378,7 @@ jsonb_object(PG_FUNCTION_ARGS)
 					 errmsg("wrong number of array subscripts")));
 	}
 
-	deconstruct_array(in_array,
+	deconstruct_array_builtin(in_array, TEXTOID, &in_datums, &in_nulls, &in_count);
-					  TEXTOID, -1, false, TYPALIGN_INT,
-					  &in_datums, &in_nulls, &in_count);
 
 	count = in_count / 2;
 
@@ -1466,13 +1464,8 @@ jsonb_object_two_arg(PG_FUNCTION_ARGS)
 	if (nkdims == 0)
 		goto close_object;
 
-	deconstruct_array(key_array,
+	deconstruct_array_builtin(key_array, TEXTOID, &key_datums, &key_nulls, &key_count);
-					  TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(val_array, TEXTOID, &val_datums, &val_nulls, &val_count);
-					  &key_datums, &key_nulls, &key_count);
-
-	deconstruct_array(val_array,
-					  TEXTOID, -1, false, TYPALIGN_INT,
-					  &val_datums, &val_nulls, &val_count);
 
 	if (key_count != val_count)
 		ereport(ERROR,

src/backend/utils/adt/jsonb_gin.c

@@ -885,9 +885,7 @@ gin_extract_jsonb_query(PG_FUNCTION_ARGS)
 		int			i,
 					j;
 
-		deconstruct_array(query,
+		deconstruct_array_builtin(query, TEXTOID, &key_datums, &key_nulls, &key_count);
-						  TEXTOID, -1, false, TYPALIGN_INT,
-						  &key_datums, &key_nulls, &key_count);
 
 		entries = (Datum *) palloc(sizeof(Datum) * key_count);
 

src/backend/utils/adt/jsonb_op.c

@@ -53,8 +53,7 @@ jsonb_exists_any(PG_FUNCTION_ARGS)
 	bool	   *key_nulls;
 	int			elem_count;
 
-	deconstruct_array(keys, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(keys, TEXTOID, &key_datums, &key_nulls, &elem_count);
-					  &key_datums, &key_nulls, &elem_count);
 
 	for (i = 0; i < elem_count; i++)
 	{
@@ -86,8 +85,7 @@ jsonb_exists_all(PG_FUNCTION_ARGS)
 	bool	   *key_nulls;
 	int			elem_count;
 
-	deconstruct_array(keys, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(keys, TEXTOID, &key_datums, &key_nulls, &elem_count);
-					  &key_datums, &key_nulls, &elem_count);
 
 	for (i = 0; i < elem_count; i++)
 	{

src/backend/utils/adt/jsonfuncs.c

@@ -1000,8 +1000,7 @@ get_path_all(FunctionCallInfo fcinfo, bool as_text)
 	if (array_contains_nulls(path))
 		PG_RETURN_NULL();
 
-	deconstruct_array(path, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(path, TEXTOID, &pathtext, &pathnulls, &npath);
-					  &pathtext, &pathnulls, &npath);
 
 	tpath = palloc(npath * sizeof(char *));
 	ipath = palloc(npath * sizeof(int));
@@ -1456,8 +1455,7 @@ get_jsonb_path_all(FunctionCallInfo fcinfo, bool as_text)
 	if (array_contains_nulls(path))
 		PG_RETURN_NULL();
 
-	deconstruct_array(path, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(path, TEXTOID, &pathtext, &pathnulls, &npath);
-					  &pathtext, &pathnulls, &npath);
 
 	res = jsonb_get_element(jb, pathtext, npath, &isnull, as_text);
 
@@ -4370,8 +4368,7 @@ jsonb_delete_array(PG_FUNCTION_ARGS)
 	if (JB_ROOT_COUNT(in) == 0)
 		PG_RETURN_JSONB_P(in);
 
-	deconstruct_array(keys, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(keys, TEXTOID, &keys_elems, &keys_nulls, &keys_len);
-					  &keys_elems, &keys_nulls, &keys_len);
 
 	if (keys_len == 0)
 		PG_RETURN_JSONB_P(in);
@@ -4523,8 +4520,7 @@ jsonb_set(PG_FUNCTION_ARGS)
 	if (JB_ROOT_COUNT(in) == 0 && !create)
 		PG_RETURN_JSONB_P(in);
 
-	deconstruct_array(path, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(path, TEXTOID, &path_elems, &path_nulls, &path_len);
-					  &path_elems, &path_nulls, &path_len);
 
 	if (path_len == 0)
 		PG_RETURN_JSONB_P(in);
@@ -4635,8 +4631,7 @@ jsonb_delete_path(PG_FUNCTION_ARGS)
 	if (JB_ROOT_COUNT(in) == 0)
 		PG_RETURN_JSONB_P(in);
 
-	deconstruct_array(path, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(path, TEXTOID, &path_elems, &path_nulls, &path_len);
-					  &path_elems, &path_nulls, &path_len);
 
 	if (path_len == 0)
 		PG_RETURN_JSONB_P(in);
@@ -4681,8 +4676,7 @@ jsonb_insert(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 				 errmsg("cannot set path in scalar")));
 
-	deconstruct_array(path, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(path, TEXTOID, &path_elems, &path_nulls, &path_len);
-					  &path_elems, &path_nulls, &path_len);
 
 	if (path_len == 0)
 		PG_RETURN_JSONB_P(in);

src/backend/utils/adt/lockfuncs.c

@@ -538,10 +538,7 @@ pg_blocking_pids(PG_FUNCTION_ARGS)
 	/* Assert we didn't overrun arrayelems[] */
 	Assert(narrayelems <= lockData->nlocks);
 
-	/* Construct array, using hardwired knowledge about int4 type */
+	PG_RETURN_ARRAYTYPE_P(construct_array_builtin(arrayelems, narrayelems, INT4OID));
-	PG_RETURN_ARRAYTYPE_P(construct_array(arrayelems, narrayelems,
-										  INT4OID,
-										  sizeof(int32), true, TYPALIGN_INT));
 }
 
 
@@ -579,10 +576,7 @@ pg_safe_snapshot_blocking_pids(PG_FUNCTION_ARGS)
 	else
 		blocker_datums = NULL;
 
-	/* Construct array, using hardwired knowledge about int4 type */
+	PG_RETURN_ARRAYTYPE_P(construct_array_builtin(blocker_datums, num_blockers, INT4OID));
-	PG_RETURN_ARRAYTYPE_P(construct_array(blocker_datums, num_blockers,
-										  INT4OID,
-										  sizeof(int32), true, TYPALIGN_INT));
 }
 
 

src/backend/utils/adt/name.c

@@ -314,11 +314,7 @@ current_schemas(PG_FUNCTION_ARGS)
 	}
 	list_free(search_path);
 
-	array = construct_array(names, i,
+	array = construct_array_builtin(names, i, NAMEOID);
-							NAMEOID,
-							NAMEDATALEN,	/* sizeof(Name) */
-							false,	/* Name is not by-val */
-							TYPALIGN_CHAR); /* alignment of Name */
 
 	PG_RETURN_POINTER(array);
 }

src/backend/utils/adt/orderedsetaggs.c

@@ -759,12 +759,10 @@ percentile_disc_multi_final(PG_FUNCTION_ARGS)
 		PG_RETURN_NULL();
 	param = PG_GETARG_ARRAYTYPE_P(1);
 
-	deconstruct_array(param, FLOAT8OID,
+	deconstruct_array_builtin(param, FLOAT8OID,
-	/* hard-wired info on type float8 */
+							  &percentiles_datum,
-					  sizeof(float8), FLOAT8PASSBYVAL, TYPALIGN_DOUBLE,
+							  &percentiles_null,
-					  &percentiles_datum,
+							  &num_percentiles);
-					  &percentiles_null,
-					  &num_percentiles);
 
 	if (num_percentiles == 0)
 		PG_RETURN_POINTER(construct_empty_array(osastate->qstate->sortColType));
@@ -883,12 +881,10 @@ percentile_cont_multi_final_common(FunctionCallInfo fcinfo,
 		PG_RETURN_NULL();
 	param = PG_GETARG_ARRAYTYPE_P(1);
 
-	deconstruct_array(param, FLOAT8OID,
+	deconstruct_array_builtin(param, FLOAT8OID,
-	/* hard-wired info on type float8 */
+							  &percentiles_datum,
-					  sizeof(float8), FLOAT8PASSBYVAL, TYPALIGN_DOUBLE,
+							  &percentiles_null,
-					  &percentiles_datum,
+							  &num_percentiles);
-					  &percentiles_null,
-					  &num_percentiles);
 
 	if (num_percentiles == 0)
 		PG_RETURN_POINTER(construct_empty_array(osastate->qstate->sortColType));

src/backend/utils/adt/pg_upgrade_support.c

@@ -214,9 +214,7 @@ binary_upgrade_create_empty_extension(PG_FUNCTION_ARGS)
 		int			ndatums;
 		int			i;
 
-		deconstruct_array(textArray,
+		deconstruct_array_builtin(textArray, TEXTOID, &textDatums, NULL, &ndatums);
-						  TEXTOID, -1, false, TYPALIGN_INT,
-						  &textDatums, NULL, &ndatums);
 		for (i = 0; i < ndatums; i++)
 		{
 			char	   *extName = TextDatumGetCString(textDatums[i]);

src/backend/utils/adt/ruleutils.c

@@ -2406,9 +2406,8 @@ pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
 					if (isnull)
 						elog(ERROR, "null indkey for index %u", indexId);
 
-					deconstruct_array(DatumGetArrayTypeP(cols),
+					deconstruct_array_builtin(DatumGetArrayTypeP(cols), INT2OID,
-									  INT2OID, 2, true, TYPALIGN_SHORT,
+											  &keys, NULL, &nKeys);
-									  &keys, NULL, &nKeys);
 
 					for (j = keyatts; j < nKeys; j++)
 					{
@@ -2531,9 +2530,8 @@ pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
 					elog(ERROR, "null conexclop for constraint %u",
 						 constraintId);
 
-				deconstruct_array(DatumGetArrayTypeP(val),
+				deconstruct_array_builtin(DatumGetArrayTypeP(val), OIDOID,
-								  OIDOID, sizeof(Oid), true, TYPALIGN_INT,
+										  &elems, NULL, &nElems);
-								  &elems, NULL, &nElems);
 
 				operators = (Oid *) palloc(nElems * sizeof(Oid));
 				for (i = 0; i < nElems; i++)
@@ -2587,9 +2585,8 @@ decompile_column_index_array(Datum column_index_array, Oid relId,
 	int			j;
 
 	/* Extract data from array of int16 */
-	deconstruct_array(DatumGetArrayTypeP(column_index_array),
+	deconstruct_array_builtin(DatumGetArrayTypeP(column_index_array), INT2OID,
-					  INT2OID, 2, true, TYPALIGN_SHORT,
+							  &keys, NULL, &nKeys);
-					  &keys, NULL, &nKeys);
 
 	for (j = 0; j < nKeys; j++)
 	{
@@ -12752,9 +12749,8 @@ get_reloptions(StringInfo buf, Datum reloptions)
 	int			noptions;
 	int			i;
 
-	deconstruct_array(DatumGetArrayTypeP(reloptions),
+	deconstruct_array_builtin(DatumGetArrayTypeP(reloptions), TEXTOID,
-					  TEXTOID, -1, false, TYPALIGN_INT,
+							  &options, NULL, &noptions);
-					  &options, NULL, &noptions);
 
 	for (i = 0; i < noptions; i++)
 	{

src/backend/utils/adt/tsvector_op.c

@@ -308,8 +308,7 @@ tsvector_setweight_by_filter(PG_FUNCTION_ARGS)
 	memcpy(tsout, tsin, VARSIZE(tsin));
 	entry = ARRPTR(tsout);
 
-	deconstruct_array(lexemes, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(lexemes, TEXTOID, &dlexemes, &nulls, &nlexemes);
-					  &dlexemes, &nulls, &nlexemes);
 
 	/*
 	 * Assuming that lexemes array is significantly shorter than tsvector we
@@ -586,8 +585,7 @@ tsvector_delete_arr(PG_FUNCTION_ARGS)
 	Datum	   *dlexemes;
 	bool	   *nulls;
 
-	deconstruct_array(lexemes, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(lexemes, TEXTOID, &dlexemes, &nulls, &nlex);
-					  &dlexemes, &nulls, &nlex);
 
 	/*
 	 * In typical use case array of lexemes to delete is relatively small. So
@@ -694,10 +692,8 @@ tsvector_unnest(PG_FUNCTION_ARGS)
 																	  1));
 			}
 
-			values[1] = PointerGetDatum(construct_array(positions, posv->npos,
+			values[1] = PointerGetDatum(construct_array_builtin(positions, posv->npos, INT2OID));
-														INT2OID, 2, true, TYPALIGN_SHORT));
+			values[2] = PointerGetDatum(construct_array_builtin(weights, posv->npos, TEXTOID));
-			values[2] = PointerGetDatum(construct_array(weights, posv->npos,
-														TEXTOID, -1, false, TYPALIGN_INT));
 		}
 		else
 		{
@@ -733,7 +729,7 @@ tsvector_to_array(PG_FUNCTION_ARGS)
 															   arrin[i].len));
 	}
 
-	array = construct_array(elements, tsin->size, TEXTOID, -1, false, TYPALIGN_INT);
+	array = construct_array_builtin(elements, tsin->size, TEXTOID);
 
 	pfree(elements);
 	PG_FREE_IF_COPY(tsin, 0);
@@ -757,7 +753,7 @@ array_to_tsvector(PG_FUNCTION_ARGS)
 				datalen = 0;
 	char	   *cur;
 
-	deconstruct_array(v, TEXTOID, -1, false, TYPALIGN_INT, &dlexemes, &nulls, &nitems);
+	deconstruct_array_builtin(v, TEXTOID, &dlexemes, &nulls, &nitems);
 
 	/*
 	 * Reject nulls and zero length strings (maybe we should just ignore them,
@@ -833,8 +829,7 @@ tsvector_filter(PG_FUNCTION_ARGS)
 	int			cur_pos = 0;
 	char		mask = 0;
 
-	deconstruct_array(weights, CHAROID, 1, true, TYPALIGN_CHAR,
+	deconstruct_array_builtin(weights, CHAROID, &dweights, &nulls, &nweights);
-					  &dweights, &nulls, &nweights);
 
 	for (i = 0; i < nweights; i++)
 	{

src/backend/utils/adt/xml.c

@@ -4017,9 +4017,9 @@ xpath_internal(text *xpath_expr_text, xmltype *data, ArrayType *namespaces,
 
 		Assert(ARR_ELEMTYPE(namespaces) == TEXTOID);
 
-		deconstruct_array(namespaces, TEXTOID, -1, false, TYPALIGN_INT,
+		deconstruct_array_builtin(namespaces, TEXTOID,
-						  &ns_names_uris, &ns_names_uris_nulls,
+								  &ns_names_uris, &ns_names_uris_nulls,
-						  &ns_count);
+								  &ns_count);
 
 		Assert((ns_count % 2) == 0);	/* checked above */
 		ns_count /= 2;			/* count pairs only */

src/backend/utils/cache/evtcache.c

@@ -228,8 +228,7 @@ DecodeTextArrayToBitmapset(Datum array)
 
 	if (ARR_NDIM(arr) != 1 || ARR_HASNULL(arr) || ARR_ELEMTYPE(arr) != TEXTOID)
 		elog(ERROR, "expected 1-D text array");
-	deconstruct_array(arr, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(arr, TEXTOID, &elems, NULL, &nelems);
-					  &elems, NULL, &nelems);
 
 	for (bms = NULL, i = 0; i < nelems; ++i)
 	{

src/backend/utils/fmgr/funcapi.c

@@ -1390,9 +1390,8 @@ get_func_arg_info(HeapTuple procTup,
 		*p_argnames = NULL;
 	else
 	{
-		deconstruct_array(DatumGetArrayTypeP(proargnames),
+		deconstruct_array_builtin(DatumGetArrayTypeP(proargnames), TEXTOID,
-						  TEXTOID, -1, false, TYPALIGN_INT,
+								  &elems, NULL, &nelems);
-						  &elems, NULL, &nelems);
 		if (nelems != numargs)	/* should not happen */
 			elog(ERROR, "proargnames must have the same number of elements as the function has arguments");
 		*p_argnames = (char **) palloc(sizeof(char *) * numargs);
@@ -1506,8 +1505,7 @@ get_func_input_arg_names(Datum proargnames, Datum proargmodes,
 		ARR_HASNULL(arr) ||
 		ARR_ELEMTYPE(arr) != TEXTOID)
 		elog(ERROR, "proargnames is not a 1-D text array or it contains nulls");
-	deconstruct_array(arr, TEXTOID, -1, false, TYPALIGN_INT,
+	deconstruct_array_builtin(arr, TEXTOID, &argnames, NULL, &numargs);
-					  &argnames, NULL, &numargs);
 	if (proargmodes != PointerGetDatum(NULL))
 	{
 		arr = DatumGetArrayTypeP(proargmodes);	/* ensure not toasted */
@@ -1621,8 +1619,7 @@ get_func_result_name(Oid functionId)
 			ARR_ELEMTYPE(arr) != TEXTOID)
 			elog(ERROR, "proargnames is not a 1-D text array of length %d or it contains nulls",
 				 numargs);
-		deconstruct_array(arr, TEXTOID, -1, false, TYPALIGN_INT,
+		deconstruct_array_builtin(arr, TEXTOID, &argnames, NULL, &nargnames);
-						  &argnames, NULL, &nargnames);
 		Assert(nargnames == numargs);
 
 		/* scan for output argument(s) */
@@ -1770,8 +1767,7 @@ build_function_result_tupdesc_d(char prokind,
 			ARR_ELEMTYPE(arr) != TEXTOID)
 			elog(ERROR, "proargnames is not a 1-D text array of length %d or it contains nulls",
 				 numargs);
-		deconstruct_array(arr, TEXTOID, -1, false, TYPALIGN_INT,
+		deconstruct_array_builtin(arr, TEXTOID, &argnames, NULL, &nargnames);
-						  &argnames, NULL, &nargnames);
 		Assert(nargnames == numargs);
 	}
 

src/backend/utils/misc/guc.c

@@ -9974,7 +9974,7 @@ pg_settings_get_flags(PG_FUNCTION_ARGS)
 	Assert(cnt <= MAX_GUC_FLAGS);
 
 	/* Returns the record as Datum */
-	a = construct_array(flags, cnt, TEXTOID, -1, false, TYPALIGN_INT);
+	a = construct_array_builtin(flags, cnt, TEXTOID);
 	PG_RETURN_ARRAYTYPE_P(a);
 }
 
@@ -11507,9 +11507,7 @@ GUCArrayAdd(ArrayType *array, const char *name, const char *value)
 					  TYPALIGN_INT /* TEXT's typalign */ );
 	}
 	else
-		a = construct_array(&datum, 1,
+		a = construct_array_builtin(&datum, 1, TEXTOID);
-							TEXTOID,
-							-1, false, TYPALIGN_INT);
 
 	return a;
 }
@@ -11576,9 +11574,7 @@ GUCArrayDelete(ArrayType *array, const char *name)
 								 false /* TEXT's typbyval */ ,
 								 TYPALIGN_INT /* TEXT's typalign */ );
 		else
-			newarray = construct_array(&d, 1,
+			newarray = construct_array_builtin(&d, 1, TEXTOID);
-									   TEXTOID,
-									   -1, false, TYPALIGN_INT);
 
 		index++;
 	}
@@ -11644,9 +11640,7 @@ GUCArrayReset(ArrayType *array)
 								 false /* TEXT's typbyval */ ,
 								 TYPALIGN_INT /* TEXT's typalign */ );
 		else
-			newarray = construct_array(&d, 1,
+			newarray = construct_array_builtin(&d, 1, TEXTOID);
-									   TEXTOID,
-									   -1, false, TYPALIGN_INT);
 
 		index++;
 		pfree(val);

src/include/utils/array.h

@@ -387,6 +387,7 @@ extern void array_bitmap_copy(bits8 *destbitmap, int destoffset,
 extern ArrayType *construct_array(Datum *elems, int nelems,
 								  Oid elmtype,
 								  int elmlen, bool elmbyval, char elmalign);
+extern ArrayType *construct_array_builtin(Datum *elems, int nelems, Oid elmtype);
 extern ArrayType *construct_md_array(Datum *elems,
 									 bool *nulls,
 									 int ndims,
@@ -401,6 +402,9 @@ extern void deconstruct_array(ArrayType *array,
 							  Oid elmtype,
 							  int elmlen, bool elmbyval, char elmalign,
 							  Datum **elemsp, bool **nullsp, int *nelemsp);
+extern void deconstruct_array_builtin(ArrayType *array,
+									  Oid elmtype,
+									  Datum **elemsp, bool **nullsp, int *nelemsp);
 extern bool array_contains_nulls(ArrayType *array);
 
 extern ArrayBuildState *initArrayResult(Oid element_type,

src/test/modules/test_rls_hooks/test_rls_hooks.c

@@ -70,7 +70,7 @@ test_rls_hooks_permissive(CmdType cmdtype, Relation relation)
 
 	policy->policy_name = pstrdup("extension policy");
 	policy->polcmd = '*';
-	policy->roles = construct_array(&role, 1, OIDOID, sizeof(Oid), true, TYPALIGN_INT);
+	policy->roles = construct_array_builtin(&role, 1, OIDOID);
 
 	/*
 	 * policy->qual = (Expr *) makeConst(BOOLOID, -1, InvalidOid,
@@ -138,7 +138,7 @@ test_rls_hooks_restrictive(CmdType cmdtype, Relation relation)
 
 	policy->policy_name = pstrdup("extension policy");
 	policy->polcmd = '*';
-	policy->roles = construct_array(&role, 1, OIDOID, sizeof(Oid), true, TYPALIGN_INT);
+	policy->roles = construct_array_builtin(&role, 1, OIDOID);
 
 	n = makeFuncCall(list_make2(makeString("pg_catalog"),
 								makeString("current_user")),