Remove dead code in nodeGatherMerge.c.

Coverity noted that the last line of gather_merge_getnext() was
unreachable, since each arm of the preceding "if" ends in a "return".
Drop it as an oversight.  In passing, improve some nearby comments.

diff --git a/src/backend/executor/nodeGatherMerge.c b/src/backend/executor/nodeGatherMerge.c
index 62a6b1866dcf385cd86d3db79c71b6ca83eb7cab..72f30ab4e6bbf9f9b1ff604bb35b6f31083dc91b 100644 (file)
--- a/src/backend/executor/nodeGatherMerge.c
+++ b/src/backend/executor/nodeGatherMerge.c
@@ -423,8 +423,8 @@ reread:
 }
 
 /*
- * Clear out a slot in the tuple table for each gather merge
- * slot and return the clear cleared slot.
+ * Clear out the tuple table slots for each gather merge input,
+ * and return a cleared slot.
  */
 static TupleTableSlot *
 gather_merge_clear_slots(GatherMergeState *gm_state)
@@ -456,19 +456,21 @@ gather_merge_getnext(GatherMergeState *gm_state)
 {
        int                     i;
 
-       /*
-        * First time through: pull the first tuple from each participate, and set
-        * up the heap.
-        */
-       if (gm_state->gm_initialized == false)
+       if (!gm_state->gm_initialized)
+       {
+               /*
+                * First time through: pull the first tuple from each participant, and
+                * set up the heap.
+                */
                gather_merge_init(gm_state);
+       }
        else
        {
                /*
                 * Otherwise, pull the next tuple from whichever participant we
-                * returned from last time, and reinsert the index into the heap,
-                * because it might now compare differently against the existing
-                * elements of the heap.
+                * returned from last time, and reinsert that participant's index into
+                * the heap, because it might now compare differently against the
+                * other elements of the heap.
                 */
                i = DatumGetInt32(binaryheap_first(gm_state->gm_heap));
 
@@ -485,11 +487,10 @@ gather_merge_getnext(GatherMergeState *gm_state)
        }
        else
        {
+               /* Return next tuple from whichever participant has the leading one */
                i = DatumGetInt32(binaryheap_first(gm_state->gm_heap));
                return gm_state->gm_slots[i];
        }
-
-       return gather_merge_clear_slots(gm_state);
 }
 
 /*