WL#4443

Changed Item according to second reviewers comments.
(checking can_be_evaluated_now in const_item)

Also fixed a bug found by first reviewer:
INSERT INTO t VALUES ((subselect)) evaluated selects before
locking.

Author: Mattias Jonsson

mysql-test/r/func_if.result

@@ -225,4 +225,3 @@ foo
 0.1
 Warnings:
 Warning	1292	Truncated incorrect DOUBLE value: 'a'
-Warning	1292	Truncated incorrect DOUBLE value: 'a'

mysql-test/r/partition_locking.result

@@ -3364,7 +3364,88 @@ DROP TABLE t1;
 # Test of subqueries in INSERT
 #
 CREATE TABLE t1 (a INT, b VARCHAR(64));
+CREATE TABLE t2 (a INT, b VARCHAR(64)) PARTITION BY HASH (a) PARTITIONS 3;
 INSERT INTO t1 VALUES (1, "test 1");
-INSERT INTO t1 VALUES (SELECT * FROM t1);
+INSERT INTO t2 VALUES (SELECT * FROM t1);
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SELECT * FROM t1)' at line 1
+FLUSH STATUS;
+INSERT INTO t2 VALUES ((SELECT a FROM t1), (SELECT b FROM t1));
+SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS
+WHERE VARIABLE_NAME LIKE 'HANDLER_%' AND VARIABLE_VALUE > 0;
+VARIABLE_NAME	VARIABLE_VALUE
+HANDLER_COMMIT	1
+HANDLER_EXTERNAL_LOCK	12
+HANDLER_READ_FIRST	2
+HANDLER_READ_KEY	2
+HANDLER_READ_RND_NEXT	4
+HANDLER_WRITE	18
+# 12 locks (3 tables + 3 partitions) x lock/unlock
+# I.e. No lock pruning possible
+DROP TABLE t1, t2;
+CREATE TABLE t1 (a INT, b INT);
+CREATE TABLE t2 (a INT, b INT) PARTITION BY HASH (a) PARTITIONS 3;
+INSERT INTO t1 VALUES (1, 1), (2, 0), (4, -1), (5, 2), (7, -3), (8, -9),
+(10, 5), (11, 9);
+FLUSH STATUS;
+INSERT INTO t2 VALUES ((SELECT max(a) FROM t1), (SELECT min(a) FROM t1));
+SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS
+WHERE VARIABLE_NAME LIKE 'HANDLER_%' AND VARIABLE_VALUE > 0;
+VARIABLE_NAME	VARIABLE_VALUE
+HANDLER_COMMIT	1
+HANDLER_EXTERNAL_LOCK	12
+HANDLER_READ_FIRST	2
+HANDLER_READ_KEY	2
+HANDLER_READ_RND_NEXT	18
+HANDLER_WRITE	18
+# 12 locks (3 tables + 3 partitions) x lock/unlock
+# I.e. No lock pruning possible
+FLUSH STATUS;
+EXPLAIN PARTITIONS INSERT INTO t2 VALUES ((SELECT max(a) FROM t1),
+(SELECT min(a) FROM t1));
+id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	SUBQUERY	t1	NULL	ALL	NULL	NULL	NULL	NULL	8	NULL
+2	SUBQUERY	t1	NULL	ALL	NULL	NULL	NULL	NULL	8	NULL
+SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS
+WHERE VARIABLE_NAME LIKE 'HANDLER_%' AND VARIABLE_VALUE > 0;
+VARIABLE_NAME	VARIABLE_VALUE
+HANDLER_COMMIT	1
+HANDLER_EXTERNAL_LOCK	12
+HANDLER_WRITE	17
+# 12 locks (3 tables + 3 partitions) x lock/unlock
+# I.e. No lock pruning possible
+FLUSH STATUS;
+INSERT INTO t2 VALUES ((SELECT a FROM t1 WHERE a = 1),
+(SELECT b FROM t1 WHERE a = 2));
+SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS
+WHERE VARIABLE_NAME LIKE 'HANDLER_%' AND VARIABLE_VALUE > 0;
+VARIABLE_NAME	VARIABLE_VALUE
+HANDLER_COMMIT	1
+HANDLER_EXTERNAL_LOCK	12
+HANDLER_READ_FIRST	2
+HANDLER_READ_KEY	2
+HANDLER_READ_RND_NEXT	18
+HANDLER_WRITE	18
+# 12 locks (3 tables + 3 partitions) x lock/unlock
+# I.e. No lock pruning possible
+FLUSH STATUS;
+EXPLAIN PARTITIONS INSERT INTO t2 VALUES ((SELECT a FROM t1 WHERE a = 1),
+(SELECT b FROM t1 WHERE a = 2));
+id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	SUBQUERY	t1	NULL	ALL	NULL	NULL	NULL	NULL	8	Using where
+2	SUBQUERY	t1	NULL	ALL	NULL	NULL	NULL	NULL	8	Using where
+SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS
+WHERE VARIABLE_NAME LIKE 'HANDLER_%' AND VARIABLE_VALUE > 0;
+VARIABLE_NAME	VARIABLE_VALUE
+HANDLER_COMMIT	1
+HANDLER_EXTERNAL_LOCK	12
+HANDLER_WRITE	17
+# 12 locks (3 tables + 3 partitions) x lock/unlock
+# I.e. No lock pruning possible
+SELECT * FROM t2 ORDER BY a, b;
+a	b
+1	0
+11	1
 DROP TABLE t1;
+DROP TABLE t2;

mysql-test/suite/opt_trace/r/range_no_prot.result

@@ -3932,11 +3932,13 @@ EXPLAIN SELECT 1 FROM
                         "chosen": true
                       } /* best_covering_index_scan */,
                       "setup_range_conditions": [
+                        {
+                          "impossible_condition": {
+                            "cause": "comparison_with_null_always_false"
+                          } /* impossible_condition */
+                        }
                       ] /* setup_range_conditions */,
-                      "group_index_range": {
-                        "chosen": false,
-                        "cause": "not_single_table"
-                      } /* group_index_range */
+                      "impossible_range": true
                     } /* range_analysis */
                   } /* rows_estimation_per_outer_row */
                 },
@@ -3963,11 +3965,13 @@ EXPLAIN SELECT 1 FROM
                         "chosen": true
                       } /* best_covering_index_scan */,
                       "setup_range_conditions": [
+                        {
+                          "impossible_condition": {
+                            "cause": "comparison_with_null_always_false"
+                          } /* impossible_condition */
+                        }
                       ] /* setup_range_conditions */,
-                      "group_index_range": {
-                        "chosen": false,
-                        "cause": "not_single_table"
-                      } /* group_index_range */
+                      "impossible_range": true
                     } /* range_analysis */
                   } /* rows_estimation_per_outer_row */
                 }
@@ -4266,11 +4270,13 @@ EXPLAIN SELECT 1 FROM
                         "chosen": true
                       } /* best_covering_index_scan */,
                       "setup_range_conditions": [
+                        {
+                          "impossible_condition": {
+                            "cause": "comparison_with_null_always_false"
+                          } /* impossible_condition */
+                        }
                       ] /* setup_range_conditions */,
-                      "group_index_range": {
-                        "chosen": false,
-                        "cause": "not_single_table"
-                      } /* group_index_range */
+                      "impossible_range": true
                     } /* range_analysis */
                   } /* rows_estimation_per_outer_row */
                 }

mysql-test/t/partition_locking.test

@@ -1552,8 +1552,43 @@ DROP TABLE t1;
 --echo # Test of subqueries in INSERT
 --echo #
 CREATE TABLE t1 (a INT, b VARCHAR(64));
+CREATE TABLE t2 (a INT, b VARCHAR(64)) PARTITION BY HASH (a) PARTITIONS 3;
 INSERT INTO t1 VALUES (1, "test 1");
 --error ER_PARSE_ERROR
-INSERT INTO t1 VALUES (SELECT * FROM t1);
+INSERT INTO t2 VALUES (SELECT * FROM t1);
+FLUSH STATUS;
+INSERT INTO t2 VALUES ((SELECT a FROM t1), (SELECT b FROM t1));
+eval $get_handler_status_counts;
+--echo # 12 locks (3 tables + 3 partitions) x lock/unlock
+--echo # I.e. No lock pruning possible
+DROP TABLE t1, t2;
+CREATE TABLE t1 (a INT, b INT);
+CREATE TABLE t2 (a INT, b INT) PARTITION BY HASH (a) PARTITIONS 3;
+INSERT INTO t1 VALUES (1, 1), (2, 0), (4, -1), (5, 2), (7, -3), (8, -9),
+                      (10, 5), (11, 9);
+FLUSH STATUS;
+INSERT INTO t2 VALUES ((SELECT max(a) FROM t1), (SELECT min(a) FROM t1));
+eval $get_handler_status_counts;
+--echo # 12 locks (3 tables + 3 partitions) x lock/unlock
+--echo # I.e. No lock pruning possible
+FLUSH STATUS;
+EXPLAIN PARTITIONS INSERT INTO t2 VALUES ((SELECT max(a) FROM t1),
+                                          (SELECT min(a) FROM t1));
+eval $get_handler_status_counts;
+--echo # 12 locks (3 tables + 3 partitions) x lock/unlock
+--echo # I.e. No lock pruning possible
+FLUSH STATUS;
+INSERT INTO t2 VALUES ((SELECT a FROM t1 WHERE a = 1),
+                       (SELECT b FROM t1 WHERE a = 2));
+eval $get_handler_status_counts;
+--echo # 12 locks (3 tables + 3 partitions) x lock/unlock
+--echo # I.e. No lock pruning possible
+FLUSH STATUS;
+EXPLAIN PARTITIONS INSERT INTO t2 VALUES ((SELECT a FROM t1 WHERE a = 1),
+                                          (SELECT b FROM t1 WHERE a = 2));
+eval $get_handler_status_counts;
+--echo # 12 locks (3 tables + 3 partitions) x lock/unlock
+--echo # I.e. No lock pruning possible
+SELECT * FROM t2 ORDER BY a, b;
 DROP TABLE t1;
-
+DROP TABLE t2;

mysql-test/t/partition_pruning.test

@@ -622,7 +622,6 @@ insert into t3 values (5),(15);
 explain partitions select * from t3 where a=11;
 explain partitions select * from t3 where a=10;
 explain partitions select * from t3 where a=20;
-
 explain partitions select * from t3 where a=30;
 
 # LIST(expr) partitioning

mysys/my_bitmap.c

@@ -557,7 +557,7 @@ uint bitmap_get_first_set(const MY_BITMAP *map)
 
 uint bitmap_get_next_set(const MY_BITMAP *map, uint bitmap_bit)
 {
-  uint word_pos, start_pos;
+  uint word_pos;
   uint32 first_word;
   my_bitmap_map *data_ptr, *end= map->last_word_ptr;
 
@@ -567,7 +567,7 @@ uint bitmap_get_next_set(const MY_BITMAP *map, uint bitmap_bit)
   bitmap_bit++;
   if (bitmap_bit >= map->n_bits)
     return MY_BIT_NONE;
-  start_pos= word_pos= bitmap_bit / 32;
+  word_pos= bitmap_bit / 32;
   data_ptr= map->bitmap + word_pos;
   first_word= *data_ptr & (0xFFFFFFFF << (bitmap_bit % 32));
   if (data_ptr == end)

sql/ha_partition.cc

@@ -7067,18 +7067,29 @@ const char *ha_partition::index_type(uint inx)
 
 enum row_type ha_partition::get_row_type() const
 {
-  handler **file;
-  enum row_type type= (*m_file)->get_row_type();
+  uint i;
+  enum row_type type;
+  DBUG_ENTER("ha_partition::get_row_type");
 
-  DBUG_ASSERT(bitmap_is_set_all(&(m_part_info->read_partitions)));
-  for (file= m_file, file++; *file; file++)
+  i= bitmap_get_first_set(&m_part_info->read_partitions);
+  DBUG_ASSERT(i < m_tot_parts);
+  if (i >= m_tot_parts)
+    DBUG_RETURN(ROW_TYPE_NOT_USED);
+
+  type= m_file[i]->get_row_type();
+  DBUG_PRINT("info", ("partition %u, row_type: %d", i, type));
+
+  for (i= bitmap_get_next_set(&m_part_info->lock_partitions, i);
+       i < m_tot_parts;
+       i= bitmap_get_next_set(&m_part_info->lock_partitions, i))
   {
-    enum row_type part_type= (*file)->get_row_type();
+    enum row_type part_type= m_file[i]->get_row_type();
+    DBUG_PRINT("info", ("partition %u, row_type: %d", i, type));
     if (part_type != type)
-      return ROW_TYPE_NOT_USED;
+      DBUG_RETURN(ROW_TYPE_NOT_USED);
   }
 
-  return type;
+  DBUG_RETURN(type);
 }
 
 

sql/item.cc

@@ -549,7 +549,8 @@ int Item::save_str_value_in_field(Field *field, String *result)
 Item::Item():
   is_expensive_cache(-1), rsize(0),
   marker(0), fixed(0),
-  collation(&my_charset_bin, DERIVATION_COERCIBLE), with_subselect(false)
+  collation(&my_charset_bin, DERIVATION_COERCIBLE), with_subselect(false),
+  tables_locked_cache(false)
 {
   maybe_null=null_value=with_sum_func=unsigned_flag=0;
   decimals= 0; max_length= 0;
@@ -597,7 +598,8 @@ Item::Item(THD *thd, Item *item):
   fixed(item->fixed),
   collation(item->collation),
   cmp_context(item->cmp_context),
-  with_subselect(item->with_subselect)
+  with_subselect(item->with_subselect),
+  tables_locked_cache(item->tables_locked_cache)
 {
   next= thd->free_list;				// Put in free list
   thd->free_list= this;
@@ -5864,6 +5866,30 @@ bool Item::eq_by_collation(Item *item, bool binary_cmp,
 }  
 
 
+/**
+  Check if it is OK to evaluate the item now.
+
+  @return true if the item can be evaluated in the current statement state.
+    @retval true  The item can be evaluated now.
+    @retval false The item can not be evaluated now,
+                  (i.e. depend on non locked table).
+
+  @note Help function to avoid optimize or exec call during prepare phase.
+*/
+
+bool Item::can_be_evaluated_now() const
+{
+  if (tables_locked_cache)
+    return true;
+  if (has_subquery())
+    const_cast<Item*>(this)->tables_locked_cache=
+                               current_thd->lex->is_query_tables_locked();
+  else
+    const_cast<Item*>(this)->tables_locked_cache= true;
+  return tables_locked_cache;
+}
+
+
 /**
   Create a field to hold a string value from an item.
 
@@ -9390,41 +9416,3 @@ void view_error_processor(THD *thd, void *data)
 {
   ((TABLE_LIST *)data)->hide_view_error(thd);
 }
-
-/*
-  Is the item a stored function which may need table access.
-
-  TODO: Either eliminate the execute of this during mysql_delete_prepare
-  or create a better/more accurate way to check if the sp may access tables;
-*/
-
-static bool is_stored_function_which_may_need_table(Item* item)
-{
-  if (item->type() == Item::FUNC_ITEM &&
-      ((Item_func*)item)->functype() == Item_func::FUNC_SP)
-    return true;
-  return false;
-}
-
-
-/**
-  Returns wether it is OK to evaluate the item now.
-
-  @param thd   Thread object
-  @param item  Item to check
-
-  @return true if only constant and is either locked or has no subquery.
-
-  @note After WL#4443 there must be no optimize or exec call during
-  prepare phase.
-*/
-
-bool can_evaluate_item_now(THD *thd, Item *item)
-{
-  if (item->const_item() &&
-      ((thd->lex->is_query_tables_locked() ||
-        (!item->has_subquery() &&
-         !is_stored_function_which_may_need_table(item)))))
-    return true;
-  return false;
-}

sql/item.h

@@ -711,6 +711,7 @@ class Item
                                            subselect. Computed by fix_fields
                                            and updated by update_used_tables. */
 
+  bool tables_locked_cache;
  public:
   // alloc & destruct is done as start of select using sql_alloc
   Item();
@@ -1194,7 +1195,12 @@ class Item
     When the default implementation of used_tables() is effective, this
     function will always return true (because used_tables() is empty).
   */
-  virtual bool const_item() const { return used_tables() == 0; }
+  virtual bool const_item() const
+  {
+    if (used_tables() == 0)
+      return can_be_evaluated_now();
+    return false;
+  }
   /* 
     Returns true if this is constant but its value may be not known yet.
     (Can be used for parameters of prep. stmts or of stored procedures.)
@@ -1573,6 +1579,7 @@ class Item
       is_expensive_cache= walk(&Item::is_expensive_processor, 0, (uchar*)0);
     return test(is_expensive_cache);
   }
+  virtual bool can_be_evaluated_now() const;
   uint32 max_char_length() const
   { return max_length / collation.collation->mbmaxlen; }
   void fix_length_and_charset(uint32 max_char_length_arg,
@@ -4322,7 +4329,6 @@ void mark_select_range_as_dependent(THD *thd,
                                     st_select_lex *current_sel,
                                     Field *found_field, Item *found_item,
                                     Item_ident *resolved_item);
-bool can_evaluate_item_now(THD *thd, Item *item);
 
 extern Cached_item *new_Cached_item(THD *thd, Item *item,
                                     bool use_result_field);