diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c
index 28802e6588..75e5bbf209 100644
--- a/src/backend/executor/nodeAgg.c
+++ b/src/backend/executor/nodeAgg.c
@@ -2704,8 +2704,8 @@ agg_refill_hash_table(AggState *aggstate)
 
 	if (spill_initialized)
 	{
-		hash_agg_update_metrics(aggstate, true, spill.npartitions);
 		hashagg_spill_finish(aggstate, &spill, batch->setno);
+		hash_agg_update_metrics(aggstate, true, spill.npartitions);
 	}
 	else
 		hash_agg_update_metrics(aggstate, true, 0);
diff --git a/src/backend/utils/sort/logtape.c b/src/backend/utils/sort/logtape.c
index d6d1e1911e..28905124f9 100644
--- a/src/backend/utils/sort/logtape.c
+++ b/src/backend/utils/sort/logtape.c
@@ -1264,9 +1264,19 @@ LogicalTapeTell(LogicalTapeSet *lts, int tapenum,
 
 /*
  * Obtain total disk space currently used by a LogicalTapeSet, in blocks.
+ *
+ * This should not be called while there are open write buffers; otherwise it
+ * may not account for buffered data.
  */
 long
 LogicalTapeSetBlocks(LogicalTapeSet *lts)
 {
-	return lts->nBlocksAllocated - lts->nHoleBlocks;
+#ifdef USE_ASSERT_CHECKING
+	for (int i = 0; i < lts->nTapes; i++)
+	{
+		LogicalTape *lt = &lts->tapes[i];
+		Assert(!lt->writing || lt->buffer == NULL);
+	}
+#endif
+	return lts->nBlocksWritten - lts->nHoleBlocks;
 }