[Feature] Support Invisible Columns

src/backend/access/common/tupdesc.c

@@ -462,6 +462,8 @@ equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2)
 			return false;
 		if (attr1->attisdropped != attr2->attisdropped)
 			return false;
+		if (attr1->attisinvisible != attr2->attisinvisible)
+			return false;
 		if (attr1->attislocal != attr2->attislocal)
 			return false;
 		if (attr1->attinhcount != attr2->attinhcount)
@@ -644,6 +646,7 @@ TupleDescInitEntry(TupleDesc desc,
 	att->atthasmissing = false;
 	att->attidentity = '\0';
 	att->attisdropped = false;
+	att->attisinvisible = false;
 	att->attislocal = true;
 	att->attinhcount = 0;
 	/* attacl, attoptions and attfdwoptions are not present in tupledescs */
@@ -703,6 +706,7 @@ TupleDescInitBuiltinEntry(TupleDesc desc,
 	att->atthasmissing = false;
 	att->attidentity = '\0';
 	att->attisdropped = false;
+	att->attisinvisible = false;
 	att->attislocal = true;
 	att->attinhcount = 0;
 	/* attacl, attoptions and attfdwoptions are not present in tupledescs */

src/backend/catalog/heap.c

@@ -152,37 +152,37 @@ static List *insert_ordered_unique_oid(List *list, Oid datum);
 static FormData_pg_attribute a1 = {
 	0, {"ctid"}, TIDOID, 0, sizeof(ItemPointerData),
 	SelfItemPointerAttributeNumber, 0, -1, -1,
-	false, 'p', 's', true, false, false, '\0', false, true, 0
+	false, 'p', 's', true, false, false, '\0', false, false, true, 0
 };
 
 static FormData_pg_attribute a2 = {
 	0, {"oid"}, OIDOID, 0, sizeof(Oid),
 	ObjectIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, '\0', false, true, 0
+	true, 'p', 'i', true, false, false, '\0', false, false, true, 0
 };
 
 static FormData_pg_attribute a3 = {
 	0, {"xmin"}, XIDOID, 0, sizeof(TransactionId),
 	MinTransactionIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, '\0', false, true, 0
+	true, 'p', 'i', true, false, false, '\0', false, false, true, 0
 };
 
 static FormData_pg_attribute a4 = {
 	0, {"cmin"}, CIDOID, 0, sizeof(CommandId),
 	MinCommandIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, '\0', false, true, 0
+	true, 'p', 'i', true, false, false, '\0', false, false, true, 0
 };
 
 static FormData_pg_attribute a5 = {
 	0, {"xmax"}, XIDOID, 0, sizeof(TransactionId),
 	MaxTransactionIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, '\0', false, true, 0
+	true, 'p', 'i', true, false, false, '\0', false, false, true, 0
 };
 
 static FormData_pg_attribute a6 = {
 	0, {"cmax"}, CIDOID, 0, sizeof(CommandId),
 	MaxCommandIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, '\0', false, true, 0
+	true, 'p', 'i', true, false, false, '\0', false, false,  true, 0
 };
 
 /*
@@ -194,20 +194,20 @@ static FormData_pg_attribute a6 = {
 static FormData_pg_attribute a7 = {
 	0, {"tableoid"}, OIDOID, 0, sizeof(Oid),
 	TableOidAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, '\0', false, true, 0
+	true, 'p', 'i', true, false, false, '\0', false, false, true, 0
 };
 
 /* POLAR px */
 static FormData_pg_attribute a8 = {
 	0, {"_px_worker_id"}, INT4OID, 0, sizeof(PxWorkerId),
 	PxWorkerIdAttributeNumber, 0, -1, -1,
-	true, 'p', 'i', true, false, false, '\0', false, true, 0
+	true, 'p', 'i', true, false, false, '\0', false, false,  true, 0
 };
 
 static FormData_pg_attribute a9 = {
 	0, {"_root_ctid"}, TIDOID, 0, sizeof(ItemPointerData),
 	RootSelfItemPointerAttributeNumber, 0, -1, -1,
-	false, 'p', 's', true, false, false, '\0', false, true, 0
+	false, 'p', 's', true, false, false, '\0', false, false,  true, 0
 };
 /* POLAR end */
 
@@ -691,6 +691,7 @@ HeapTuple heaptuple_from_pg_attribute(Relation pg_attribute_rel,
 	values[Anum_pg_attribute_atthasmissing - 1] = BoolGetDatum(new_attribute->atthasmissing);
 	values[Anum_pg_attribute_attidentity - 1] = CharGetDatum(new_attribute->attidentity);
 	values[Anum_pg_attribute_attisdropped - 1] = BoolGetDatum(new_attribute->attisdropped);
+	values[Anum_pg_attribute_attisinvisible - 1] = BoolGetDatum(new_attribute->attisinvisible);
 	values[Anum_pg_attribute_attislocal - 1] = BoolGetDatum(new_attribute->attislocal);
 	values[Anum_pg_attribute_attinhcount - 1] = Int32GetDatum(new_attribute->attinhcount);
 	values[Anum_pg_attribute_attcollation - 1] = ObjectIdGetDatum(new_attribute->attcollation);

src/backend/commands/sequence.c

@@ -162,6 +162,7 @@ DefineSequence(ParseState *pstate, CreateSeqStmt *seq)
 		ColumnDef  *coldef = makeNode(ColumnDef);
 
 		coldef->inhcount = 0;
+		coldef->is_invisible = false;
 		coldef->is_local = true;
 		coldef->is_not_null = true;
 		coldef->is_from_type = false;

src/backend/commands/tablecmds.c

@@ -381,6 +381,10 @@ static ObjectAddress ATExecDropNotNull(Relation rel, const char *colName, LOCKMO
 static void ATPrepSetNotNull(Relation rel, bool recurse, bool recursing);
 static ObjectAddress ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 				 const char *colName, LOCKMODE lockmode);
+static ObjectAddress ATExecSetVisible(AlteredTableInfo *tab, Relation rel,
+				 const char *colName, LOCKMODE lockmode);
+static ObjectAddress ATExecSetInvisible(AlteredTableInfo *tab, Relation rel,
+				 const char *colName, LOCKMODE lockmode);
 static ObjectAddress ATExecColumnDefault(Relation rel, const char *colName,
 					Node *newDefault, LOCKMODE lockmode);
 static ObjectAddress ATExecAddIdentity(Relation rel, const char *colName,
@@ -772,6 +776,9 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
 
 		if (colDef->identity)
 			attr->attidentity = colDef->identity;
+
+		if (colDef->is_invisible)
+			attr->attisinvisible = colDef->is_invisible;
 	}
 
 	/*
@@ -3527,6 +3534,14 @@ AlterTableGetLockLevel(List *cmds)
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
+				/*
+				 * changing visibilty can affect concurrent SELECTs
+				 */
+			case AT_SetInvisible:
+			case AT_SetVisible:
+				cmd_lockmode = AccessExclusiveLock;
+				break;
+
 				/*
 				 * These subcommands affect write operations only.
 				 */
@@ -3816,6 +3831,16 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			/* No command-specific prep needed */
 			pass = AT_PASS_ADD_CONSTR;
 			break;
+		case AT_SetVisible:	/* ALTER COLUMN SET VISIBLE */
+			ATSimplePermissions(rel, ATT_TABLE | ATT_FOREIGN_TABLE);
+			ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
+			/* No command-specific prep needed */
+			pass = AT_PASS_ADD_CONSTR;
+		case AT_SetInvisible:	/* ALTER COLUMN SET INVISIBLE */
+			ATSimplePermissions(rel, ATT_TABLE | ATT_FOREIGN_TABLE);
+			ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
+			/* No command-specific prep needed */
+			pass = AT_PASS_ADD_CONSTR;
 		case AT_SetStatistics:	/* ALTER COLUMN SET STATISTICS */
 			ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
 			/* Performs own permission checks */
@@ -4149,6 +4174,12 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		case AT_SetNotNull:		/* ALTER COLUMN SET NOT NULL */
 			address = ATExecSetNotNull(tab, rel, cmd->name, lockmode);
 			break;
+		case AT_SetVisible:	/* ALTER COLUMN SET VISIBLE */
+			address = ATExecSetVisible(tab, rel, cmd->name, lockmode);
+			break;
+		case AT_SetInvisible:	/* ALTER COLUMN SET INVISIBLE */
+			address = ATExecSetInvisible(tab, rel, cmd->name, lockmode);
+			break;
 		case AT_SetStatistics:	/* ALTER COLUMN SET STATISTICS */
 			address = ATExecSetStatistics(rel, cmd->name, cmd->num, cmd->def, lockmode);
 			break;
@@ -5646,6 +5677,7 @@ ATExecAddColumn(List **wqueue, AlteredTableInfo *tab, Relation rel,
 	attribute.atthasmissing = false;
 	attribute.attidentity = colDef->identity;
 	attribute.attisdropped = false;
+	attribute.attisinvisible = colDef->is_invisible;
 	attribute.attislocal = colDef->is_local;
 	attribute.attinhcount = colDef->inhcount;
 	attribute.attcollation = collOid;
@@ -6228,6 +6260,118 @@ ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 	return address;
 }
 
+/*
+ * Return the address of the modified column.  If the column was already Invisible,
+ * InvalidObjectAddress is returned.
+ */
+static ObjectAddress
+ATExecSetVisible(AlteredTableInfo *tab, Relation rel,
+				 const char *colName, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	AttrNumber	attnum;
+	Relation	attr_rel;
+	ObjectAddress address;
+
+	/*
+	 * lookup the attribute
+	 */
+	attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
+
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						colName, RelationGetRelationName(rel))));
+
+	attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
+
+	/* Prevent them from altering a system attribute */
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"",
+						colName)));
+
+	if (((Form_pg_attribute) GETSTRUCT(tuple))->attisinvisible)
+	{
+		((Form_pg_attribute) GETSTRUCT(tuple))->attisinvisible = false;
+
+		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
+
+		ObjectAddressSubSet(address, RelationRelationId,
+							RelationGetRelid(rel), attnum);
+	}
+	else
+		address = InvalidObjectAddress;
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel), attnum);
+
+	heap_close(attr_rel, RowExclusiveLock);
+	heap_freetuple(tuple);
+
+	return address;
+}
+
+/*
+ * Return the address of the modified column.  If the column was already Invisible,
+ * InvalidObjectAddress is returned.
+ */
+static ObjectAddress
+ATExecSetInvisible(AlteredTableInfo *tab, Relation rel,
+				 const char *colName, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	AttrNumber	attnum;
+	Relation	attr_rel;
+	ObjectAddress address;
+
+	/*
+	 * lookup the attribute
+	 */
+	attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
+
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						colName, RelationGetRelationName(rel))));
+
+	attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
+
+	/* Prevent them from altering a system attribute */
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"",
+						colName)));
+
+	if (!((Form_pg_attribute) GETSTRUCT(tuple))->attisinvisible)
+	{
+		((Form_pg_attribute) GETSTRUCT(tuple))->attisinvisible = true;
+
+		CatalogTupleUpdate(attr_rel, &tuple->t_self, tuple);
+
+		ObjectAddressSubSet(address, RelationRelationId,
+							RelationGetRelid(rel), attnum);
+	}
+	else
+		address = InvalidObjectAddress;
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel), attnum);
+
+	heap_close(attr_rel, RowExclusiveLock);
+	heap_freetuple(tuple);
+
+	return address;
+}
+
 /*
  * ALTER TABLE ALTER COLUMN SET/DROP DEFAULT
  *

src/backend/nodes/makefuncs.c

@@ -493,6 +493,7 @@ makeColumnDef(const char *colname, Oid typeOid, int32 typmod, Oid collOid)
 	n->colname = pstrdup(colname);
 	n->typeName = makeTypeNameFromOid(typeOid, typmod);
 	n->inhcount = 0;
+	n->is_invisible = false;
 	n->is_local = true;
 	n->is_not_null = false;
 	n->is_from_type = false;

src/backend/nodes/outfuncs.c

@@ -3733,6 +3733,10 @@ _outConstraint(StringInfo str, const Constraint *node)
 			WRITE_CHAR_FIELD(generated_when);
 			break;
 
+		case CONSTR_INVISIBLE:
+			appendStringInfoString(str, "INVISIBLE");
+			break;
+
 		case CONSTR_CHECK:
 			appendStringInfoString(str, "CHECK");
 			WRITE_BOOL_FIELD(is_no_inherit);