In the final emptying phase of the new GiST buffering build, set the

queuedForEmptying flag correctly on buffer when adding it to the queue.
Also, don't add buffer to the queue if it's there already. These were
harmless oversights; failing to set the flag just means that a buffer might
get added to the queue twice if more tuples are added to it (although that
can't actually happen at this point because all the upper buffers have
already been emptied), and having the same buffer twice in the emptying
queue is harmless. But better be tidy.

diff --git a/src/backend/access/gist/gistbuild.c b/src/backend/access/gist/gistbuild.c
index 58f1ef221e12196dc735a0aeece0036aaff0669a..0046c7b3ab3a106cf1343070bf39acb7db1cdc55 100644 (file)
--- a/src/backend/access/gist/gistbuild.c
+++ b/src/backend/access/gist/gistbuild.c
@@ -964,10 +964,14 @@ gistEmptyAllBuffers(GISTBuildState *buildstate)
                                 * Add this buffer to the emptying queue, and proceed to empty
                                 * the queue.
                                 */
-                               MemoryContextSwitchTo(gfbb->context);
-                               gfbb->bufferEmptyingQueue =
-                                       lcons(nodeBuffer, gfbb->bufferEmptyingQueue);
-                               MemoryContextSwitchTo(buildstate->tmpCtx);
+                               if (!nodeBuffer->queuedForEmptying)
+                               {
+                                       MemoryContextSwitchTo(gfbb->context);
+                                       nodeBuffer->queuedForEmptying = true;
+                                       gfbb->bufferEmptyingQueue =
+                                               lcons(nodeBuffer, gfbb->bufferEmptyingQueue);
+                                       MemoryContextSwitchTo(buildstate->tmpCtx);
+                               }
                                gistProcessEmptyingQueue(buildstate);
                        }
                        else