3 files changed, 41 insertions, 11 deletions
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 4da4dc84580..24d3765aa20 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -2147,6 +2147,19 @@ heapam_scan_bitmap_next_tuple(TableScanDesc scan,
 			 */
 			ExecStoreAllNullTuple(slot);
 			bscan->rs_empty_tuples_pending--;
+
+			/*
+			 * We do not recheck all NULL tuples. Because the streaming read
+			 * API only yields TBMIterateResults for blocks actually fetched
+			 * from the heap, we must unset `recheck` ourselves here to ensure
+			 * correct results.
+			 *
+			 * Our read stream callback accrues a count of empty tuples to
+			 * emit and then emits them after emitting tuples from the next
+			 * fetched block. If no blocks need fetching, we'll emit the
+			 * accrued count at the end of the scan.
+			 */
+			*recheck = false;
 			return true;
 		}
 
@@ -2510,13 +2523,14 @@ BitmapHeapScanNextBlock(TableScanDesc scan,
 		}
 
 		/*
-		 * Bitmap is exhausted. Time to emit empty tuples if relevant. We emit
-		 * all empty tuples at the end instead of emitting them per block we
-		 * skip fetching. This is necessary because the streaming read API
-		 * will only return TBMIterateResults for blocks actually fetched.
-		 * When we skip fetching a block, we keep track of how many empty
-		 * tuples to emit at the end of the BitmapHeapScan. We do not recheck
-		 * all NULL tuples.
+		 * The bitmap is exhausted. Now emit any remaining empty tuples. The
+		 * read stream API only returns TBMIterateResults for blocks actually
+		 * fetched from the heap. Our callback will accrue a count of empty
+		 * tuples to emit for all blocks we skipped fetching. So, if we skip
+		 * fetching heap blocks at the end of the relation (or no heap blocks
+		 * are fetched) we need to ensure we emit empty tuples before ending
+		 * the scan. We don't recheck empty tuples so ensure `recheck` is
+		 * unset.
 		 */
 		*recheck = false;
 		return bscan->rs_empty_tuples_pending > 0;
diff --git a/src/test/regress/expected/bitmapops.out b/src/test/regress/expected/bitmapops.out
index 3570973e3ca..64068e0469c 100644
--- a/src/test/regress/expected/bitmapops.out
+++ b/src/test/regress/expected/bitmapops.out
@@ -8,7 +8,7 @@
 -- there's a maximum number of a,b combinations in the table.
 -- That allows us to test all the different combinations of
 -- lossy and non-lossy pages with the minimum amount of data
-CREATE TABLE bmscantest (a int, b int, t text);
+CREATE TABLE bmscantest (a int, b int, t text) WITH (autovacuum_enabled = false);
 INSERT INTO bmscantest
   SELECT (r%53), (r%59), 'foooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo'
   FROM generate_series(1,70000) r;
@@ -20,7 +20,17 @@ set enable_indexscan=false;
 set enable_seqscan=false;
 -- Lower work_mem to trigger use of lossy bitmaps
 set work_mem = 64;
--- Test bitmap-and.
+-- Test bitmap-and without the skip fetch optimization.
+SELECT count(*) FROM bmscantest WHERE a = 1 AND b = 1;
+ count 
+-------
+    23
+(1 row)
+
+-- Test that we return correct results when using the skip fetch optimization
+-- VACUUM FREEZE will set all the pages in the relation all-visible, enabling
+-- the optimization.
+VACUUM (FREEZE) bmscantest;
 SELECT count(*) FROM bmscantest WHERE a = 1 AND b = 1;
  count 
 -------
diff --git a/src/test/regress/sql/bitmapops.sql b/src/test/regress/sql/bitmapops.sql
index 498f4721b51..1b175f6ff96 100644
--- a/src/test/regress/sql/bitmapops.sql
+++ b/src/test/regress/sql/bitmapops.sql
@@ -12,7 +12,7 @@
 -- That allows us to test all the different combinations of
 -- lossy and non-lossy pages with the minimum amount of data
 
-CREATE TABLE bmscantest (a int, b int, t text);
+CREATE TABLE bmscantest (a int, b int, t text) WITH (autovacuum_enabled = false);
 
 INSERT INTO bmscantest
   SELECT (r%53), (r%59), 'foooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo'
@@ -29,8 +29,14 @@ set enable_seqscan=false;
 -- Lower work_mem to trigger use of lossy bitmaps
 set work_mem = 64;
 
+-- Test bitmap-and without the skip fetch optimization.
+SELECT count(*) FROM bmscantest WHERE a = 1 AND b = 1;
+
+-- Test that we return correct results when using the skip fetch optimization
+-- VACUUM FREEZE will set all the pages in the relation all-visible, enabling
+-- the optimization.
+VACUUM (FREEZE) bmscantest;
 
--- Test bitmap-and.
 SELECT count(*) FROM bmscantest WHERE a = 1 AND b = 1;
 
 -- Test bitmap-or.