Merge remote-tracking branch 'origin/10.5' into 10.6

mysql-test/main/range.result

@@ -3635,6 +3635,25 @@ SELECT * FROM t1 LEFT JOIN t2 ON a = pk WHERE b >= 0 AND pk IS NULL;
 a pk b
 DROP TABLE t1, t2;
 SET @@optimizer_switch= @save_optimizer_switch;
+
+# MDEV-28858 Wrong result with table elimination combined with
+# not_null_range_scan
+#
+CREATE TABLE t1 (a INT, b INT) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (10,1),(null,2);
+CREATE TABLE t2 (pk INT PRIMARY KEY) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (1),(2);
+SET @save_optimizer_switch= @@optimizer_switch;
+SET optimizer_switch= 'not_null_range_scan=on';
+SELECT t1.b FROM t1 LEFT JOIN t2 ON t1.a = t2.pk WHERE t1.a IS NULL ORDER BY t1.b;
+b
+2
+SET optimizer_switch= 'not_null_range_scan=off';
+SELECT t1.b FROM t1 LEFT JOIN t2 ON t1.a = t2.pk WHERE t1.a IS NULL ORDER BY t1.b;
+b
+2
+SET @@optimizer_switch=@save_optimizer_switch;
+drop table t1,t2;
 #
 # End of 10.5 tests
 #

mysql-test/main/range.test

@@ -2492,6 +2492,24 @@ DROP TABLE t1, t2;
 
 SET @@optimizer_switch= @save_optimizer_switch;
 
+--echo
+--echo # MDEV-28858 Wrong result with table elimination combined with
+--echo # not_null_range_scan
+--echo #
+
+CREATE TABLE t1 (a INT, b INT) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (10,1),(null,2);
+CREATE TABLE t2 (pk INT PRIMARY KEY) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (1),(2);
+
+SET @save_optimizer_switch= @@optimizer_switch;
+SET optimizer_switch= 'not_null_range_scan=on';
+SELECT t1.b FROM t1 LEFT JOIN t2 ON t1.a = t2.pk WHERE t1.a IS NULL ORDER BY t1.b;
+SET optimizer_switch= 'not_null_range_scan=off';
+SELECT t1.b FROM t1 LEFT JOIN t2 ON t1.a = t2.pk WHERE t1.a IS NULL ORDER BY t1.b;
+SET @@optimizer_switch=@save_optimizer_switch;
+drop table t1,t2;
+
 --echo #
 --echo # End of 10.5 tests
 --echo #

mysql-test/main/range_mrr_icp.result

@@ -3624,6 +3624,25 @@ SELECT * FROM t1 LEFT JOIN t2 ON a = pk WHERE b >= 0 AND pk IS NULL;
 a pk b
 DROP TABLE t1, t2;
 SET @@optimizer_switch= @save_optimizer_switch;
+
+# MDEV-28858 Wrong result with table elimination combined with
+# not_null_range_scan
+#
+CREATE TABLE t1 (a INT, b INT) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (10,1),(null,2);
+CREATE TABLE t2 (pk INT PRIMARY KEY) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (1),(2);
+SET @save_optimizer_switch= @@optimizer_switch;
+SET optimizer_switch= 'not_null_range_scan=on';
+SELECT t1.b FROM t1 LEFT JOIN t2 ON t1.a = t2.pk WHERE t1.a IS NULL ORDER BY t1.b;
+b
+2
+SET optimizer_switch= 'not_null_range_scan=off';
+SELECT t1.b FROM t1 LEFT JOIN t2 ON t1.a = t2.pk WHERE t1.a IS NULL ORDER BY t1.b;
+b
+2
+SET @@optimizer_switch=@save_optimizer_switch;
+drop table t1,t2;
 #
 # End of 10.5 tests
 #

sql/sql_select.cc

@@ -29976,11 +29976,12 @@ bool build_notnull_conds_for_range_scans(JOIN *join, Item *cond,
 
  DBUG_ENTER("build_notnull_conds_for_range_scans");
 
- for (JOIN_TAB *s= join->join_tab + join->const_tables ;
+ for (JOIN_TAB *s= join->join_tab;
  s < join->join_tab + join->table_count ; s++)
  {
  /* Clear all needed bitmaps to mark found fields */
- if (allowed & s->table->map)
+ if ((allowed & s->table->map) &&
+ !(s->table->map && join->const_table_map))
  bitmap_clear_all(&s->table->tmp_set);
  }
 
@@ -29995,17 +29996,18 @@ bool build_notnull_conds_for_range_scans(JOIN *join, Item *cond,
  For each table t from 'allowed' build a conjunction of NOT NULL predicates
  constructed for all found fields if they are included in some indexes.
  If the construction of the conjunction succeeds attach the formula to
- t->table->notnull_cond. The condition will be used to look for complementary
- range scans.
+ t->table->notnull_cond. The condition will be used to look for
+ complementary range scans.
  */
- for (JOIN_TAB *s= join->join_tab + join->const_tables ;
+ for (JOIN_TAB *s= join->join_tab ;
  s < join->join_tab + join->table_count ; s++)
  {
  TABLE *tab= s->table;
  List<Item> notnull_list;
  Item *notnull_cond= 0;
 
- if (!(allowed & tab->map))
+ if (!(allowed & tab->map) ||
+ (s->table->map && join->const_table_map))
  continue;
 
  for (Field** field_ptr= tab->field; *field_ptr; field_ptr++)

tpool/tpool_generic.cc

@@ -327,21 +327,22 @@ class thread_pool_generic : public thread_pool
  int m_period;
  std::mutex m_mtx;
  bool m_on;
- std::atomic<bool> m_running;
+ std::atomic<int> m_running;
 
  void run()
  {
  /*
  In rare cases, multiple callbacks can be scheduled,
- e.g with set_time(0,0) in a loop.
- We do not allow parallel execution, as user is not prepared.
+ at the same time,. e.g with set_time(0,0) in a loop.
+ We do not allow parallel execution, since it is against the expectations.
  */
- bool expected = false;
- if (!m_running.compare_exchange_strong(expected, true))
+ if (m_running.fetch_add(1, std::memory_order_acquire) > 0)
  return;
-
- m_callback(m_data);
- m_running = false;
+ do
+ {
+ m_callback(m_data);
+ }
+ while (m_running.fetch_sub(1, std::memory_order_release) != 1);
 
  if (m_pool && m_period)
  {