Allow per-column foreign data wrapper options.

Shigeru Hanada, with fairly minor editing by me.

1 files changed, 106 insertions, 0 deletions

diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 82bb756c75e..4509cdab900 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -346,6 +346,8 @@ static void ATPrepAlterColumnType(List **wqueue,
 static bool ATColumnChangeRequiresRewrite(Node *expr, AttrNumber varattno);
 static void ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
 					  AlterTableCmd *cmd, LOCKMODE lockmode);
+static void ATExecAlterColumnGenericOptions(Relation rel, const char *colName,
+								List *options, LOCKMODE lockmode);
 static void ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab, LOCKMODE lockmode);
 static void ATPostAlterTypeParse(Oid oldId, char *cmd,
 					 List **wqueue, LOCKMODE lockmode, bool rewrite);
@@ -2648,6 +2650,7 @@ AlterTableGetLockLevel(List *cmds)
 			case AT_DropNotNull:		/* may change some SQL plans */
 			case AT_SetNotNull:
 			case AT_GenericOptions:
+			case AT_AlterColumnGenericOptions:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -2925,6 +2928,12 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			ATPrepAlterColumnType(wqueue, tab, rel, recurse, recursing, cmd, lockmode);
 			pass = AT_PASS_ALTER_TYPE;
 			break;
+		case AT_AlterColumnGenericOptions:
+			ATSimplePermissions(rel, ATT_FOREIGN_TABLE);
+			/* This command never recurses */
+			/* No command-specific prep needed */
+			pass = AT_PASS_MISC;
+			break;
 		case AT_ChangeOwner:	/* ALTER OWNER */
 			/* This command never recurses */
 			/* No command-specific prep needed */
@@ -3169,6 +3178,9 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		case AT_AlterColumnType:		/* ALTER COLUMN TYPE */
 			ATExecAlterColumnType(tab, rel, cmd, lockmode);
 			break;
+		case AT_AlterColumnGenericOptions:	/* ALTER COLUMN OPTIONS */
+			ATExecAlterColumnGenericOptions(rel, cmd->name, (List *) cmd->def, lockmode);
+			break;
 		case AT_ChangeOwner:	/* ALTER OWNER */
 			ATExecChangeOwner(RelationGetRelid(rel),
 							  get_role_oid(cmd->name, false),
@@ -7397,6 +7409,100 @@ ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
 	heap_freetuple(heapTup);
 }
 
+static void
+ATExecAlterColumnGenericOptions(Relation rel,
+								const char *colName,
+								List *options,
+								LOCKMODE lockmode)
+{
+	Relation	ftrel;
+	Relation	attrel;
+	ForeignServer *server;
+	ForeignDataWrapper *fdw;
+	HeapTuple	tuple;
+	HeapTuple	newtuple;
+	bool		isnull;
+	Datum		repl_val[Natts_pg_attribute];
+	bool		repl_null[Natts_pg_attribute];
+	bool		repl_repl[Natts_pg_attribute];
+	Datum		datum;
+	Form_pg_foreign_table fttableform;
+	Form_pg_attribute atttableform;
+
+	if (options == NIL)
+		return;
+
+	/* First, determine FDW validator associated to the foreign table. */
+	ftrel = heap_open(ForeignTableRelationId, AccessShareLock);
+	tuple = SearchSysCache1(FOREIGNTABLEREL, rel->rd_id);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_OBJECT),
+				 errmsg("foreign table \"%s\" does not exist",
+						RelationGetRelationName(rel))));
+	fttableform = (Form_pg_foreign_table) GETSTRUCT(tuple);
+	server = GetForeignServer(fttableform->ftserver);
+	fdw = GetForeignDataWrapper(server->fdwid);
+
+	heap_close(ftrel, AccessShareLock);
+	ReleaseSysCache(tuple);
+
+	attrel = heap_open(AttributeRelationId, RowExclusiveLock);
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						colName, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	if (atttableform->attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", colName)));
+
+
+	/* Initialize buffers for new tuple values */
+	memset(repl_val, 0, sizeof(repl_val));
+	memset(repl_null, false, sizeof(repl_null));
+	memset(repl_repl, false, sizeof(repl_repl));
+
+	/* Extract the current options */
+	datum = SysCacheGetAttr(ATTNAME,
+							tuple,
+							Anum_pg_attribute_attfdwoptions,
+							&isnull);
+	if (isnull)
+		datum = PointerGetDatum(NULL);
+
+	/* Transform the options */
+	datum = transformGenericOptions(AttributeRelationId,
+									datum,
+									options,
+									fdw->fdwvalidator);
+
+	if (PointerIsValid(DatumGetPointer(datum)))
+		repl_val[Anum_pg_attribute_attfdwoptions - 1] = datum;
+	else
+		repl_null[Anum_pg_attribute_attfdwoptions - 1] = true;
+
+	repl_repl[Anum_pg_attribute_attfdwoptions - 1] = true;
+
+	/* Everything looks good - update the tuple */
+
+	newtuple = heap_modify_tuple(tuple, RelationGetDescr(attrel),
+								 repl_val, repl_null, repl_repl);
+	ReleaseSysCache(tuple);
+
+	simple_heap_update(attrel, &newtuple->t_self, newtuple);
+	CatalogUpdateIndexes(attrel, newtuple);
+
+	heap_close(attrel, RowExclusiveLock);
+
+	heap_freetuple(newtuple);
+}
+
 /*
  * Cleanup after we've finished all the ALTER TYPE operations for a
  * particular relation.  We have to drop and recreate all the indexes