Fix a problem with parallel workers being unable to restore role.

check_role() tries to verify that the user has permission to become the
requested role, but this is inappropriate in a parallel worker, which
needs to exactly recreate the master's authorization settings.  So skip
the check in that case.

This fixes a bug in commit 924bcf4f16d54c55310b28f77686608684734f42.

diff --git a/src/backend/access/transam/parallel.c b/src/backend/access/transam/parallel.c
index e09bdb20b0d9d56056a858989a652ad0de10a435..9c7428f5d6c6efdf4ca274001c1c384f4856c7dc 100644 (file)
--- a/src/backend/access/transam/parallel.c
+++ b/src/backend/access/transam/parallel.c
@@ -96,6 +96,9 @@ int                   ParallelWorkerNumber = -1;
 /* Is there a parallel message pending which we need to receive? */
 bool           ParallelMessagePending = false;
 
+/* Are we initializing a parallel worker? */
+bool           InitializingParallelWorker = false;
+
 /* Pointer to our fixed parallel state. */
 static FixedParallelState *MyFixedParallelState;
 
@@ -815,6 +818,9 @@ ParallelWorkerMain(Datum main_arg)
        char       *tstatespace;
        StringInfoData msgbuf;
 
+       /* Set flag to indicate that we're initializing a parallel worker. */
+       InitializingParallelWorker = true;
+
        /* Establish signal handlers. */
        pqsignal(SIGTERM, die);
        BackgroundWorkerUnblockSignals();
@@ -942,6 +948,7 @@ ParallelWorkerMain(Datum main_arg)
         * We've initialized all of our state now; nothing should change
         * hereafter.
         */
+       InitializingParallelWorker = false;
        EnterParallelMode();
 
        /*

diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c
index 2d0a44effe797e7f3d0c297dd5efb7989743b0dc..16c122a22bc7f1916cd5b2a1f84fb622e380cc23 100644 (file)
--- a/src/backend/commands/variable.c
+++ b/src/backend/commands/variable.c
@@ -19,6 +19,7 @@
 #include <ctype.h>
 
 #include "access/htup_details.h"
+#include "access/parallel.h"
 #include "access/xact.h"
 #include "access/xlog.h"
 #include "catalog/pg_authid.h"
@@ -877,9 +878,12 @@ check_role(char **newval, void **extra, GucSource source)
                ReleaseSysCache(roleTup);
 
                /*
-                * Verify that session user is allowed to become this role
+                * Verify that session user is allowed to become this role, but
+                * skip this in parallel mode, where we must blindly recreate the
+                * parallel leader's state.
                 */
-               if (!is_member_of_role(GetSessionUserId(), roleid))
+               if (!InitializingParallelWorker &&
+                       !is_member_of_role(GetSessionUserId(), roleid))
                {
                        GUC_check_errcode(ERRCODE_INSUFFICIENT_PRIVILEGE);
                        GUC_check_errmsg("permission denied to set role \"%s\"",

diff --git a/src/include/access/parallel.h b/src/include/access/parallel.h
index b029c1e88317fecb43916231bc22ccdea9d3f085..44f0616cb86547fbe96ca5e164a9fe51ac00f1b0 100644 (file)
--- a/src/include/access/parallel.h
+++ b/src/include/access/parallel.h
@@ -48,6 +48,7 @@ typedef struct ParallelContext
 
 extern bool ParallelMessagePending;
 extern int     ParallelWorkerNumber;
+extern bool InitializingParallelWorker;
 
 #define                IsParallelWorker()              (ParallelWorkerNumber >= 0)