Handle empty result set in libpqrcv_exec

Always return tupleslot and tupledesc from libpqrcv_exec.  This avoids
requiring callers to handle that separately.

Author: Petr Jelinek <petr.jelinek@2ndquadrant.com>
Reported-by: Michael Banck <michael.banck@credativ.de>

diff --git a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
index 4dd8eef1f92d6cf8bcb611145cd49d241e8010ec..9d7bb25d3976a305cc940b288a391b26851cd803 100644 (file)
--- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
+++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
@@ -803,10 +803,6 @@ libpqrcv_processTuples(PGresult *pgres, WalRcvExecResult *walres,
        MemoryContext   rowcontext;
        MemoryContext   oldcontext;
 
-       /* No point in doing anything here if there were no tuples returned. */
-       if (PQntuples(pgres) == 0)
-               return;
-
        /* Make sure we got expected number of fields. */
        if (nfields != nRetTypes)
                ereport(ERROR,
@@ -824,6 +820,10 @@ libpqrcv_processTuples(PGresult *pgres, WalRcvExecResult *walres,
                                                   PQfname(pgres, coln), retTypes[coln], -1, 0);
        attinmeta = TupleDescGetAttInMetadata(walres->tupledesc);
 
+       /* No point in doing more here if there were no tuples returned. */
+       if (PQntuples(pgres) == 0)
+               return;
+
        /* Create temporary context for local allocations. */
        rowcontext = AllocSetContextCreate(CurrentMemoryContext,
                                                                           "libpqrcv query result context",