PG16 - Add GENERIC_PLAN option to EXPLAIN

src/backend/distributed/planner/multi_explain.c

@@ -992,12 +992,18 @@ BuildRemoteExplainQuery(char *queryString, ExplainState *es)
 	appendStringInfo(explainQuery,
 					 "EXPLAIN (ANALYZE %s, VERBOSE %s, "
 					 "COSTS %s, BUFFERS %s, WAL %s, "
+#if PG_VERSION_NUM >= PG_VERSION_16
+					 "GENERIC_PLAN %s, "
+#endif
 					 "TIMING %s, SUMMARY %s, FORMAT %s) %s",
 					 es->analyze ? "TRUE" : "FALSE",
 					 es->verbose ? "TRUE" : "FALSE",
 					 es->costs ? "TRUE" : "FALSE",
 					 es->buffers ? "TRUE" : "FALSE",
 					 es->wal ? "TRUE" : "FALSE",
+#if PG_VERSION_NUM >= PG_VERSION_16
+					 es->generic ? "TRUE" : "FALSE",
+#endif
 					 es->timing ? "TRUE" : "FALSE",
 					 es->summary ? "TRUE" : "FALSE",
 					 formatStr,

src/test/regress/expected/pg16.out

@@ -65,6 +65,46 @@ SET citus.log_remote_commands TO OFF;
 -- only verifying it works and not printing log
 -- remote commands because it can be flaky
 VACUUM (ONLY_DATABASE_STATS);
+-- New GENERIC_PLAN option in EXPLAIN
+-- Relevant PG commit:
+-- https://github.com/postgres/postgres/commit/3c05284
+CREATE TABLE tenk1 (
+	unique1 int4,
+	unique2 int4,
+    thousand int4
+);
+SELECT create_distributed_table('tenk1', 'unique1');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+SET citus.log_remote_commands TO on;
+EXPLAIN (GENERIC_PLAN) SELECT unique1 FROM tenk1 WHERE thousand = 1000;
+NOTICE:  issuing BEGIN TRANSACTION ISOLATION LEVEL READ COMMITTED;SELECT assign_distributed_transaction_id(xx, xx, 'xxxxxxx');
+DETAIL:  on server postgres@localhost:xxxxx connectionId: xxxxxxx
+NOTICE:  issuing SAVEPOINT citus_explain_savepoint
+DETAIL:  on server postgres@localhost:xxxxx connectionId: xxxxxxx
+NOTICE:  issuing EXPLAIN (ANALYZE FALSE, VERBOSE FALSE, COSTS TRUE, BUFFERS FALSE, WAL FALSE, GENERIC_PLAN TRUE, TIMING FALSE, SUMMARY FALSE, FORMAT TEXT) SELECT unique1 FROM pg16.tenk1_950001 tenk1 WHERE (thousand OPERATOR(pg_catalog.=) 1000)
+DETAIL:  on server postgres@localhost:xxxxx connectionId: xxxxxxx
+NOTICE:  issuing ROLLBACK TO SAVEPOINT citus_explain_savepoint
+DETAIL:  on server postgres@localhost:xxxxx connectionId: xxxxxxx
+NOTICE:  issuing COMMIT
+DETAIL:  on server postgres@localhost:xxxxx connectionId: xxxxxxx
+                                   QUERY PLAN
+---------------------------------------------------------------------
+ Custom Scan (Citus Adaptive)  (cost=0.00..0.00 rows=0 width=0)
+   Task Count: 1
+   Tasks Shown: All
+   ->  Task
+         Node: host=localhost port=xxxxx dbname=regression
+         ->  Seq Scan on tenk1_950001 tenk1  (cost=0.00..35.50 rows=10 width=4)
+               Filter: (thousand = 1000)
+(7 rows)
+
+EXPLAIN (GENERIC_PLAN, ANALYZE) SELECT unique1 FROM tenk1 WHERE thousand = 1000;
+ERROR:  EXPLAIN options ANALYZE and GENERIC_PLAN cannot be used together
+SET citus.log_remote_commands TO off;
 -- Proper error when creating statistics without a name on a Citus table
 -- Relevant PG commit:
 -- https://github.com/postgres/postgres/commit/624aa2a13bd02dd584bb0995c883b5b93b2152df

src/test/regress/sql/pg16.sql

@@ -45,6 +45,22 @@ SET citus.log_remote_commands TO OFF;
 -- remote commands because it can be flaky
 VACUUM (ONLY_DATABASE_STATS);
 
+-- New GENERIC_PLAN option in EXPLAIN
+-- Relevant PG commit:
+-- https://github.com/postgres/postgres/commit/3c05284
+
+CREATE TABLE tenk1 (
+	unique1 int4,
+	unique2 int4,
+    thousand int4
+);
+SELECT create_distributed_table('tenk1', 'unique1');
+
+SET citus.log_remote_commands TO on;
+EXPLAIN (GENERIC_PLAN) SELECT unique1 FROM tenk1 WHERE thousand = 1000;
+EXPLAIN (GENERIC_PLAN, ANALYZE) SELECT unique1 FROM tenk1 WHERE thousand = 1000;
+SET citus.log_remote_commands TO off;
+
 -- Proper error when creating statistics without a name on a Citus table
 -- Relevant PG commit:
 -- https://github.com/postgres/postgres/commit/624aa2a13bd02dd584bb0995c883b5b93b2152df