4 files changed, 43 insertions, 6 deletions
diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index df0cd775588..d5bee10cd4b 100644
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -1402,10 +1402,6 @@ ParallelWorkerMain(Datum main_arg)
 	libraryspace = shm_toc_lookup(toc, PARALLEL_KEY_LIBRARY, false);
 	StartTransactionCommand();
 	RestoreLibraryState(libraryspace);
-
-	/* Restore GUC values from launching backend. */
-	gucspace = shm_toc_lookup(toc, PARALLEL_KEY_GUC, false);
-	RestoreGUCState(gucspace);
 	CommitTransactionCommand();
 
 	/* Crank up a transaction state appropriate to a parallel worker. */
@@ -1448,6 +1444,14 @@ ParallelWorkerMain(Datum main_arg)
 	InvalidateSystemCaches();
 
 	/*
+	 * Restore GUC values from launching backend.  We can't do this earlier,
+	 * because GUC check hooks that do catalog lookups need to see the same
+	 * database state as the leader.
+	 */
+	gucspace = shm_toc_lookup(toc, PARALLEL_KEY_GUC, false);
+	RestoreGUCState(gucspace);
+
+	/*
 	 * Restore current role id.  Skip verifying whether session user is
 	 * allowed to become this role and blindly restore the leader's state for
 	 * current role.
diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c
index e5ddcda0b4a..b2336ad7efd 100644
--- a/src/backend/commands/variable.c
+++ b/src/backend/commands/variable.c
@@ -519,14 +519,16 @@ check_transaction_read_only(bool *newval, void **extra, GucSource source)
  * We allow idempotent changes at any time, but otherwise this can only be
  * changed in a toplevel transaction that has not yet taken a snapshot.
  *
- * As in check_transaction_read_only, allow it if not inside a transaction.
+ * As in check_transaction_read_only, allow it if not inside a transaction,
+ * or if restoring state in a parallel worker.
  */
 bool
 check_XactIsoLevel(int *newval, void **extra, GucSource source)
 {
 	int			newXactIsoLevel = *newval;
 
-	if (newXactIsoLevel != XactIsoLevel && IsTransactionState())
+	if (newXactIsoLevel != XactIsoLevel &&
+		IsTransactionState() && !InitializingParallelWorker)
 	{
 		if (FirstSnapshotSet)
 		{
@@ -561,6 +563,10 @@ check_XactIsoLevel(int *newval, void **extra, GucSource source)
 bool
 check_transaction_deferrable(bool *newval, void **extra, GucSource source)
 {
+	/* Just accept the value when restoring state in a parallel worker */
+	if (InitializingParallelWorker)
+		return true;
+
 	if (IsSubTransaction())
 	{
 		GUC_check_errcode(ERRCODE_ACTIVE_SQL_TRANSACTION);
diff --git a/src/test/regress/expected/select_parallel.out b/src/test/regress/expected/select_parallel.out
index 91f74fe47a3..3c6887fcb97 100644
--- a/src/test/regress/expected/select_parallel.out
+++ b/src/test/regress/expected/select_parallel.out
@@ -1219,3 +1219,21 @@ SELECT 1 FROM tenk1_vw_sec
 (9 rows)
 
 rollback;
+-- test that a newly-created session role propagates to workers.
+begin;
+create role regress_parallel_worker;
+set session authorization regress_parallel_worker;
+select current_setting('session_authorization');
+     current_setting     
+-------------------------
+ regress_parallel_worker
+(1 row)
+
+set force_parallel_mode = 1;
+select current_setting('session_authorization');
+     current_setting     
+-------------------------
+ regress_parallel_worker
+(1 row)
+
+rollback;
diff --git a/src/test/regress/sql/select_parallel.sql b/src/test/regress/sql/select_parallel.sql
index 62fb68c7a04..11d861584ef 100644
--- a/src/test/regress/sql/select_parallel.sql
+++ b/src/test/regress/sql/select_parallel.sql
@@ -462,3 +462,12 @@ SELECT 1 FROM tenk1_vw_sec
   WHERE (SELECT sum(f1) FROM int4_tbl WHERE f1 < unique1) < 100;
 
 rollback;
+
+-- test that a newly-created session role propagates to workers.
+begin;
+create role regress_parallel_worker;
+set session authorization regress_parallel_worker;
+select current_setting('session_authorization');
+set force_parallel_mode = 1;
+select current_setting('session_authorization');
+rollback;