1 files changed, 45 insertions, 14 deletions

diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index 82ed9e41d9f..53fedb33c5a 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -3621,6 +3621,9 @@ create_foreign_modify(EState *estate,
 
 			Assert(!attr->attisdropped);
 
+			/* Ignore generated columns; they are set to DEFAULT */
+			if (attr->attgenerated)
+				continue;
 			getTypeOutputInfo(attr->atttypid, &typefnoid, &isvarlena);
 			fmgr_info(typefnoid, &fmstate->p_flinfo[fmstate->p_nums]);
 			fmstate->p_nums++;
@@ -3806,6 +3809,7 @@ convert_prep_stmt_params(PgFdwModifyState *fmstate,
 	/* get following parameters from slot */
 	if (slot != NULL && fmstate->target_attrs != NIL)
 	{
+		TupleDesc	tupdesc = RelationGetDescr(fmstate->rel);
 		int			nestlevel;
 		ListCell   *lc;
 
@@ -3814,9 +3818,13 @@ convert_prep_stmt_params(PgFdwModifyState *fmstate,
 		foreach(lc, fmstate->target_attrs)
 		{
 			int			attnum = lfirst_int(lc);
+			Form_pg_attribute attr = TupleDescAttr(tupdesc, attnum - 1);
 			Datum		value;
 			bool		isnull;
 
+			/* Ignore generated columns; they are set to DEFAULT */
+			if (attr->attgenerated)
+				continue;
 			value = slot_getattr(slot, attnum, &isnull);
 			if (isnull)
 				p_values[pindex] = NULL;
@@ -4728,6 +4736,7 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 	List	   *commands = NIL;
 	bool		import_collate = true;
 	bool		import_default = false;
+	bool		import_generated = true;
 	bool		import_not_null = true;
 	ForeignServer *server;
 	UserMapping *mapping;
@@ -4747,6 +4756,8 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 			import_collate = defGetBoolean(def);
 		else if (strcmp(def->defname, "import_default") == 0)
 			import_default = defGetBoolean(def);
+		else if (strcmp(def->defname, "import_generated") == 0)
+			import_generated = defGetBoolean(def);
 		else if (strcmp(def->defname, "import_not_null") == 0)
 			import_not_null = defGetBoolean(def);
 		else
@@ -4808,13 +4819,24 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 		 * include a schema name for types/functions in other schemas, which
 		 * is what we want.
 		 */
+		appendStringInfoString(&buf,
+							   "SELECT relname, "
+							   "  attname, "
+							   "  format_type(atttypid, atttypmod), "
+							   "  attnotnull, ");
+
+		/* Generated columns are supported since Postgres 12 */
+		if (PQserverVersion(conn) >= 120000)
+			appendStringInfoString(&buf,
+								   "  attgenerated, "
+								   "  pg_get_expr(adbin, adrelid), ");
+		else
+			appendStringInfoString(&buf,
+								   "  NULL, "
+								   "  pg_get_expr(adbin, adrelid), ");
+
 		if (import_collate)
 			appendStringInfoString(&buf,
-								   "SELECT relname, "
-								   "  attname, "
-								   "  format_type(atttypid, atttypmod), "
-								   "  attnotnull, "
-								   "  pg_get_expr(adbin, adrelid), "
 								   "  collname, "
 								   "  collnsp.nspname "
 								   "FROM pg_class c "
@@ -4831,11 +4853,6 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 								   "    collnsp.oid = collnamespace ");
 		else
 			appendStringInfoString(&buf,
-								   "SELECT relname, "
-								   "  attname, "
-								   "  format_type(atttypid, atttypmod), "
-								   "  attnotnull, "
-								   "  pg_get_expr(adbin, adrelid), "
 								   "  NULL, NULL "
 								   "FROM pg_class c "
 								   "  JOIN pg_namespace n ON "
@@ -4911,6 +4928,7 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 				char	   *attname;
 				char	   *typename;
 				char	   *attnotnull;
+				char	   *attgenerated;
 				char	   *attdefault;
 				char	   *collname;
 				char	   *collnamespace;
@@ -4922,12 +4940,14 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 				attname = PQgetvalue(res, i, 1);
 				typename = PQgetvalue(res, i, 2);
 				attnotnull = PQgetvalue(res, i, 3);
-				attdefault = PQgetisnull(res, i, 4) ? (char *) NULL :
+				attgenerated = PQgetisnull(res, i, 4) ? (char *) NULL :
 					PQgetvalue(res, i, 4);
-				collname = PQgetisnull(res, i, 5) ? (char *) NULL :
+				attdefault = PQgetisnull(res, i, 5) ? (char *) NULL :
 					PQgetvalue(res, i, 5);
-				collnamespace = PQgetisnull(res, i, 6) ? (char *) NULL :
+				collname = PQgetisnull(res, i, 6) ? (char *) NULL :
 					PQgetvalue(res, i, 6);
+				collnamespace = PQgetisnull(res, i, 7) ? (char *) NULL :
+					PQgetvalue(res, i, 7);
 
 				if (first_item)
 					first_item = false;
@@ -4955,9 +4975,20 @@ postgresImportForeignSchema(ImportForeignSchemaStmt *stmt, Oid serverOid)
 									 quote_identifier(collname));
 
 				/* Add DEFAULT if needed */
-				if (import_default && attdefault != NULL)
+				if (import_default && attdefault != NULL &&
+					(!attgenerated || !attgenerated[0]))
 					appendStringInfo(&buf, " DEFAULT %s", attdefault);
 
+				/* Add GENERATED if needed */
+				if (import_generated && attgenerated != NULL &&
+					attgenerated[0] == ATTRIBUTE_GENERATED_STORED)
+				{
+					Assert(attdefault != NULL);
+					appendStringInfo(&buf,
+									 " GENERATED ALWAYS AS (%s) STORED",
+									 attdefault);
+				}
+
 				/* Add NOT NULL if needed */
 				if (import_not_null && attnotnull[0] == 't')
 					appendStringInfoString(&buf, " NOT NULL");