Fix use of wrong variable in _hash_kill_items()

In 82467f627bd I somehow ended up using 'so->currPos.buf' instead of the 'buf'
variable, which is incorrect when the buffer is not already pinned. At the
very least this can lead to assertion failures

Unfortunately this shows that this code path was not covered. Expand
src/test/modules/index/specs/killtuples.spec to test it.  Until now the
'result' step always reported either a 0 or 1 buffer accesses, but when
exercising hash overflows, more buffers are accessed.  To avoid depending on
the precise number of accesses, change the result step to return whether there
were any heap accesses. That makes the change a lot more verbose, but still
seems worth it.

Reported-by: Alexander Kuzmenkov <akuzmenkov@tigerdata.com>
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Reported-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://postgr.es/m/vjtmvwvbxt7w5uyacxpzibpj65ewcb7uqaqbhd4arvnjbp5jqz%405ksdh6fsyqve
Discussion: https://postgr.es/m/b9de8d05-3b02-4a27-9b0b-03972fa4bfd3@iki.fi

diff --git a/src/backend/access/hash/hashutil.c b/src/backend/access/hash/hashutil.c
index 3e16119d0276c68915bfd6e4dbc3261bad651eeb..081adbc88a602e5fe60cb97555780c8101e1f317 100644 (file)
--- a/src/backend/access/hash/hashutil.c
+++ b/src/backend/access/hash/hashutil.c
@@ -600,7 +600,7 @@ _hash_kill_items(IndexScanDesc scan)
                                         * update the page while just holding a share lock. If we
                                         * are not allowed, there's no point continuing.
                                         */
-                                       if (!BufferBeginSetHintBits(so->currPos.buf))
+                                       if (!BufferBeginSetHintBits(buf))
                                                goto unlock_page;
                                }
 
@@ -621,7 +621,7 @@ _hash_kill_items(IndexScanDesc scan)
        if (killedsomething)
        {
                opaque->hasho_flag |= LH_PAGE_HAS_DEAD_TUPLES;
-               BufferFinishSetHintBits(so->currPos.buf, true, true);
+               BufferFinishSetHintBits(buf, true, true);
        }
 
 unlock_page:

diff --git a/src/test/modules/index/expected/killtuples.out b/src/test/modules/index/expected/killtuples.out
index be7ddd756ef0e7c4b708a56a3dcf66ce18e10345..a3db2c409368975c95808ecac59016f55c09de3e 100644 (file)
--- a/src/test/modules/index/expected/killtuples.out
+++ b/src/test/modules/index/expected/killtuples.out
@@ -17,10 +17,10 @@ Index Scan using kill_prior_tuple_btree on kill_prior_tuple (actual rows=1.00 lo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
@@ -33,10 +33,10 @@ Index Scan using kill_prior_tuple_btree on kill_prior_tuple (actual rows=1.00 lo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step delete: DELETE FROM kill_prior_tuple;
@@ -51,10 +51,10 @@ Index Scan using kill_prior_tuple_btree on kill_prior_tuple (actual rows=0.00 lo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
@@ -67,10 +67,10 @@ Index Scan using kill_prior_tuple_btree on kill_prior_tuple (actual rows=0.00 lo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                0
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+f                    
 (1 row)
 
 step drop_table: DROP TABLE IF EXISTS kill_prior_tuple;
@@ -93,10 +93,10 @@ Index Scan using kill_prior_tuple_gist on kill_prior_tuple (actual rows=1.00 loo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
@@ -109,10 +109,10 @@ Index Scan using kill_prior_tuple_gist on kill_prior_tuple (actual rows=1.00 loo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step delete: DELETE FROM kill_prior_tuple;
@@ -127,10 +127,10 @@ Index Scan using kill_prior_tuple_gist on kill_prior_tuple (actual rows=0.00 loo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
@@ -143,10 +143,10 @@ Index Scan using kill_prior_tuple_gist on kill_prior_tuple (actual rows=0.00 loo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                0
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+f                    
 (1 row)
 
 step drop_table: DROP TABLE IF EXISTS kill_prior_tuple;
@@ -170,10 +170,10 @@ Index Scan using kill_prior_tuple_gist on kill_prior_tuple (actual rows=1.00 loo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
@@ -186,10 +186,10 @@ Index Scan using kill_prior_tuple_gist on kill_prior_tuple (actual rows=1.00 loo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step delete: DELETE FROM kill_prior_tuple;
@@ -204,10 +204,10 @@ Index Scan using kill_prior_tuple_gist on kill_prior_tuple (actual rows=0.00 loo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
@@ -220,10 +220,10 @@ Index Scan using kill_prior_tuple_gist on kill_prior_tuple (actual rows=0.00 loo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step drop_table: DROP TABLE IF EXISTS kill_prior_tuple;
@@ -246,10 +246,10 @@ Index Scan using kill_prior_tuple_hash on kill_prior_tuple (actual rows=1.00 loo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
@@ -262,10 +262,10 @@ Index Scan using kill_prior_tuple_hash on kill_prior_tuple (actual rows=1.00 loo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step delete: DELETE FROM kill_prior_tuple;
@@ -280,10 +280,10 @@ Index Scan using kill_prior_tuple_hash on kill_prior_tuple (actual rows=0.00 loo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
@@ -296,10 +296,85 @@ Index Scan using kill_prior_tuple_hash on kill_prior_tuple (actual rows=0.00 loo
 (3 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                0
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+f                    
+(1 row)
+
+step drop_table: DROP TABLE IF EXISTS kill_prior_tuple;
+
+starting permutation: create_table fill_same create_hash flush disable_seq disable_bitmap measure access flush result measure access flush result delete flush measure access flush result measure access flush result drop_table
+step create_table: CREATE TEMPORARY TABLE kill_prior_tuple(key int not null, cat text not null);
+step fill_same: INSERT INTO kill_prior_tuple(key, cat) SELECT 1, 'a' FROM generate_series(1, 408) g(i);
+step create_hash: CREATE INDEX kill_prior_tuple_hash ON kill_prior_tuple USING hash (key);
+step flush: SELECT FROM pg_stat_force_next_flush();
+step disable_seq: SET enable_seqscan = false;
+step disable_bitmap: SET enable_bitmapscan = false;
+step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
+step access: EXPLAIN (ANALYZE, COSTS OFF, TIMING OFF, SUMMARY OFF, BUFFERS OFF) SELECT * FROM kill_prior_tuple WHERE key = 1;
+QUERY PLAN                                                                             
+---------------------------------------------------------------------------------------
+Index Scan using kill_prior_tuple_hash on kill_prior_tuple (actual rows=408.00 loops=1)
+  Index Cond: (key = 1)                                                                
+  Index Searches: 1                                                                    
+(3 rows)
+
+step flush: SELECT FROM pg_stat_force_next_flush();
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
+(1 row)
+
+step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
+step access: EXPLAIN (ANALYZE, COSTS OFF, TIMING OFF, SUMMARY OFF, BUFFERS OFF) SELECT * FROM kill_prior_tuple WHERE key = 1;
+QUERY PLAN                                                                             
+---------------------------------------------------------------------------------------
+Index Scan using kill_prior_tuple_hash on kill_prior_tuple (actual rows=408.00 loops=1)
+  Index Cond: (key = 1)                                                                
+  Index Searches: 1                                                                    
+(3 rows)
+
+step flush: SELECT FROM pg_stat_force_next_flush();
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
+(1 row)
+
+step delete: DELETE FROM kill_prior_tuple;
+step flush: SELECT FROM pg_stat_force_next_flush();
+step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
+step access: EXPLAIN (ANALYZE, COSTS OFF, TIMING OFF, SUMMARY OFF, BUFFERS OFF) SELECT * FROM kill_prior_tuple WHERE key = 1;
+QUERY PLAN                                                                           
+-------------------------------------------------------------------------------------
+Index Scan using kill_prior_tuple_hash on kill_prior_tuple (actual rows=0.00 loops=1)
+  Index Cond: (key = 1)                                                              
+  Index Searches: 1                                                                  
+(3 rows)
+
+step flush: SELECT FROM pg_stat_force_next_flush();
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
+(1 row)
+
+step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
+step access: EXPLAIN (ANALYZE, COSTS OFF, TIMING OFF, SUMMARY OFF, BUFFERS OFF) SELECT * FROM kill_prior_tuple WHERE key = 1;
+QUERY PLAN                                                                           
+-------------------------------------------------------------------------------------
+Index Scan using kill_prior_tuple_hash on kill_prior_tuple (actual rows=0.00 loops=1)
+  Index Cond: (key = 1)                                                              
+  Index Searches: 1                                                                  
+(3 rows)
+
+step flush: SELECT FROM pg_stat_force_next_flush();
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+f                    
 (1 row)
 
 step drop_table: DROP TABLE IF EXISTS kill_prior_tuple;
@@ -326,10 +401,10 @@ Bitmap Heap Scan on kill_prior_tuple (actual rows=0.00 loops=1)
 (6 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step measure: UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple');
@@ -345,10 +420,10 @@ Bitmap Heap Scan on kill_prior_tuple (actual rows=0.00 loops=1)
 (6 rows)
 
 step flush: SELECT FROM pg_stat_force_next_flush();
-step result: SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
-new_heap_accesses
------------------
-                1
+step result: SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple';
+has_new_heap_accesses
+---------------------
+t                    
 (1 row)
 
 step drop_table: DROP TABLE IF EXISTS kill_prior_tuple;

diff --git a/src/test/modules/index/specs/killtuples.spec b/src/test/modules/index/specs/killtuples.spec
index 77fe8c689a7930eeb600d9a9fa5a08220024b1b7..3b98ff9f76d8db988e7914647126f2add46063b4 100644 (file)
--- a/src/test/modules/index/specs/killtuples.spec
+++ b/src/test/modules/index/specs/killtuples.spec
@@ -36,12 +36,14 @@ step fill_10 { INSERT INTO kill_prior_tuple(key, cat) SELECT g.i, 'a' FROM gener
 
 step fill_500 { INSERT INTO kill_prior_tuple(key, cat) SELECT g.i, 'a' FROM generate_series(1, 500) g(i); }
 
+step fill_same { INSERT INTO kill_prior_tuple(key, cat) SELECT 1, 'a' FROM generate_series(1, 408) g(i); }
+
 # column-less select to make output easier to read
 step flush { SELECT FROM pg_stat_force_next_flush(); }
 
 step measure { UPDATE counter SET heap_accesses = (SELECT heap_blks_read + heap_blks_hit FROM pg_statio_all_tables WHERE relname = 'kill_prior_tuple'); }
 
-step result { SELECT heap_blks_read + heap_blks_hit - counter.heap_accesses AS new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple'; }
+step result { SELECT ((heap_blks_read + heap_blks_hit - counter.heap_accesses) > 0) AS has_new_heap_accesses FROM counter, pg_statio_all_tables WHERE relname = 'kill_prior_tuple'; }
 
 step access { EXPLAIN (ANALYZE, COSTS OFF, TIMING OFF, SUMMARY OFF, BUFFERS OFF) SELECT * FROM kill_prior_tuple WHERE key = 1; }
 
@@ -116,6 +118,17 @@ permutation
   measure access flush result
   drop_table
 
+# Test the hash special case of use of the overflow page due to lots of duplicates
+permutation
+  create_table fill_same create_hash flush
+  disable_seq disable_bitmap
+  measure access flush result
+  measure access flush result
+  delete flush
+  measure access flush result
+  measure access flush result
+  drop_table
+
 # # Similar to first permutation, except that gin does not have killtuples support
 permutation
   create_table fill_500 create_ext_btree_gin create_gin flush