Bug#10178 - failure to find a row in heap table by concurrent UPDATEs

Bug#10568 - Function 'LAST_DAY(date)' does not return NULL for invalid argument.
Manual merge.

include/my_global.h

@@ -295,10 +295,8 @@ C_MODE_END
 #include <alloca.h>
 #endif
 #ifdef HAVE_ATOMIC_ADD
-#if defined(__ia64__)
 #define new my_arg_new
 #define need_to_restore_new 1
-#endif
 C_MODE_START
 #include <asm/atomic.h>
 C_MODE_END

mysql-test/r/heap_hash.result

@@ -231,18 +231,19 @@ explain select * from t1 where a='aaad';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	a	a	8	const	1	Using where
 insert into t1 select * from t1;
+flush tables;
 explain select * from t1 where a='aaaa';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 explain select * from t1 where a='aaab';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 explain select * from t1 where a='aaac';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 explain select * from t1 where a='aaad';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 flush tables;
 explain select * from t1 where a='aaaa';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -261,16 +262,16 @@ delete from t1;
 insert into t1 select * from t2;
 explain select * from t1 where a='aaaa';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 explain select * from t1 where a='aaab';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 explain select * from t1 where a='aaac';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 explain select * from t1 where a='aaad';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ref	a	a	8	const	1	Using where
+1	SIMPLE	t1	ref	a	a	8	const	2	Using where
 drop table t1, t2;
 create table t1 (
 id int unsigned not null primary key auto_increment, 
@@ -345,14 +346,14 @@ insert into t3 select name, name from t1;
 show index from t3;
 Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment
 t3	1	a	1	a	NULL	NULL	NULL	NULL		HASH	
-t3	1	a	2	b	NULL	15	NULL	NULL		HASH	
+t3	1	a	2	b	NULL	13	NULL	NULL		HASH	
 show index from t3;
 Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment
 t3	1	a	1	a	NULL	NULL	NULL	NULL		HASH	
-t3	1	a	2	b	NULL	15	NULL	NULL		HASH	
+t3	1	a	2	b	NULL	13	NULL	NULL		HASH	
 explain select * from t1 ignore key(btree_idx), t3 where t1.name='matt' and t3.a = concat('',t1.name) and t3.b=t1.name;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t3	ref	a	a	44	const,const	6	Using where
+1	SIMPLE	t3	ref	a	a	44	const,const	7	Using where
 1	SIMPLE	t1	ref	heap_idx	heap_idx	22	const	7	Using where
 drop table t1, t2, t3;
 create temporary table t1 ( a int, index (a) ) engine=memory;

mysql-test/t/heap_hash.test

@@ -169,6 +169,8 @@ explain select * from t1 where a='aaac';
 explain select * from t1 where a='aaad';
 insert into t1 select * from t1;
 
+# avoid statistics differences between normal and ps-protocol tests
+flush tables;
 explain select * from t1 where a='aaaa';
 explain select * from t1 where a='aaab';
 explain select * from t1 where a='aaac';

sql/ha_heap.cc

@@ -65,7 +65,15 @@ int ha_heap::open(const char *name, int mode, uint test_if_locked)
   {
     /* Initialize variables for the opened table */
     set_keys_for_scanning();
-    update_key_stats();
+    /*
+      We cannot run update_key_stats() here because we do not have a
+      lock on the table. The 'records' count might just be changed
+      temporarily at this moment and we might get wrong statistics (Bug
+      #10178). Instead we request for update. This will be done in
+      ha_heap::info(), which is always called before key statistics are
+      used.
+    */
+    key_stats_ok= FALSE;
   }
   return (file ? 0 : 1);
 }
@@ -118,6 +126,8 @@ void ha_heap::update_key_stats()
     }
   }
   records_changed= 0;
+  /* At the end of update_key_stats() we can proudly claim they are OK. */
+  key_stats_ok= TRUE;
 }
 
 
@@ -132,7 +142,7 @@ int ha_heap::write_row(byte * buf)
   res= heap_write(file,buf);
   if (!res && (++records_changed*HEAP_STATS_UPDATE_THRESHOLD > 
                file->s->records))
-    update_key_stats();
+    key_stats_ok= FALSE;
   return res;
 }
 
@@ -145,7 +155,7 @@ int ha_heap::update_row(const byte * old_data, byte * new_data)
   res= heap_update(file,old_data,new_data);
   if (!res && ++records_changed*HEAP_STATS_UPDATE_THRESHOLD > 
               file->s->records)
-    update_key_stats();
+    key_stats_ok= FALSE;
   return res;
 }
 
@@ -156,7 +166,7 @@ int ha_heap::delete_row(const byte * buf)
   res= heap_delete(file,buf);
   if (!res && table->s->tmp_table == NO_TMP_TABLE && 
       ++records_changed*HEAP_STATS_UPDATE_THRESHOLD > file->s->records)
-    update_key_stats();
+    key_stats_ok= FALSE;
   return res;
 }
 
@@ -278,6 +288,13 @@ void ha_heap::info(uint flag)
   delete_length= info.deleted * info.reclength;
   if (flag & HA_STATUS_AUTO)
     auto_increment_value= info.auto_increment;
+  /*
+    If info() is called for the first time after open(), we will still
+    have to update the key statistics. Hoping that a table lock is now
+    in place.
+  */
+  if (! key_stats_ok)
+    update_key_stats();
 }
 
 int ha_heap::extra(enum ha_extra_function operation)
@@ -289,7 +306,7 @@ int ha_heap::delete_all_rows()
 {
   heap_clear(file);
   if (table->s->tmp_table == NO_TMP_TABLE)
-    update_key_stats();
+    key_stats_ok= FALSE;
   return 0;
 }
 
@@ -448,6 +465,9 @@ ha_rows ha_heap::records_in_range(uint inx, key_range *min_key,
       min_key->flag != HA_READ_KEY_EXACT ||
       max_key->flag != HA_READ_AFTER_KEY)
     return HA_POS_ERROR;			// Can only use exact keys
+
+  /* Assert that info() did run. We need current statistics here. */
+  DBUG_ASSERT(key_stats_ok);
   return key->rec_per_key[key->key_parts-1];
 }
 

sql/ha_heap.h

@@ -29,8 +29,10 @@ class ha_heap: public handler
   key_map btree_keys;
   /* number of records changed since last statistics update */
   uint    records_changed;
+  bool    key_stats_ok;
 public:
-  ha_heap(TABLE *table): handler(table), file(0), records_changed(0) {}
+  ha_heap(TABLE *table): handler(table), file(0), records_changed(0),
+      key_stats_ok(0) {}
   ~ha_heap() {}
   const char *table_type() const
   {