Fix assert failure triggered by "CREATE INDEX CONCURRENTLY"

src/backend/commands/indexcmds.c

@@ -5444,6 +5444,17 @@ update_relispartition(Oid relationId, bool newval)
 static inline void
 set_indexsafe_procflags(void)
 {
+	/*
+	 * A catalog snapshot taken earlier in this transaction (for example, by
+	 * resource-group slot assignment during StartTransaction) leaves a valid
+	 * xmin advertised in MyProc.  Drop it here so the assertion below holds;
+	 * CREATE INDEX CONCURRENTLY phases must not hold any snapshot at this
+	 * point anyway.
+	 */
+	if (MyProc->xid != InvalidTransactionId ||
+		MyProc->xmin != InvalidTransactionId)
+		InvalidateCatalogSnapshot();
+
 	/*
 	 * This should only be called before installing xid or xmin in MyProc;
 	 * otherwise, concurrent processes could see an Xmin that moves backwards.

src/test/isolation2/expected/resgroup/resgroup_transaction.out

@@ -237,3 +237,16 @@ DROP
 -- cleanup
 DROP VIEW rg_test_monitor;
 DROP
+
+-- ----------------------------------------------------------------------
+-- Test: "CREATE INDEX CONCURRENTLY" when compiled with enable-cassert
+-- ----------------------------------------------------------------------
+
+CREATE TABLE t(a text, b text);
+CREATE
+CREATE INDEX CONCURRENTLY t_idx ON t(a, b);
+CREATE
+DROP INDEX CONCURRENTLY t_idx;
+DROP
+DROP TABLE t;
+DROP

src/test/isolation2/sql/resgroup/resgroup_transaction.sql

@@ -134,3 +134,12 @@ DROP FUNCTION rg_drop_func();
 
 -- cleanup
 DROP VIEW rg_test_monitor;
+
+-- ----------------------------------------------------------------------
+-- Test: "CREATE INDEX CONCURRENTLY" when compiled with enable-cassert
+-- ----------------------------------------------------------------------
+
+CREATE TABLE t(a text, b text);
+CREATE INDEX CONCURRENTLY t_idx ON t(a, b);
+DROP INDEX CONCURRENTLY t_idx;
+DROP TABLE t;