bk commit into 5.0 tree (evgen:1.2144) BUG#19077

[eugene]

Below is the list of changes that have just been committed into a local
5.0 repository of evgen. When evgen does a push these changes will
be propagated to the main repository and, within 24 hours after the
push, to the public repository.
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see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html

ChangeSet
  1.2144 06/05/17 22:51:16 evgen@stripped +5 -0
  Fixed bug#19077: Too early applied subselect optimization leads to wrong
  result.
  
  The convert_constant_item() functions converts constant items to ints on
  prepare phase to optimize execution speed. But due to locking schema
  subselects evaluated at this phase will return wrong result.
  
  New flag with_subselect is added to the Item class. It shows that expression
  which this item represents is a subselect or contains a subselect.
  It is set to 0 by default.
  For subselects it is set to 1 in the Item_subselect constructor.
  For Item_func and Item_cond derived items it is set after fixing any argument
  in Item_func::fix_fields() and Item_cond::fix_fields accordingly.
  The convert_constant_item() function now doesn't convert a constant item
  with the with_subselect flag set.

  sql/item.cc
    1.223 06/05/17 22:49:16 evgen@stripped +1 -0
    Fixed bug#19077: Too early applied subselect optimization leads to wrong
    result.
    Set new with_subselect flag to default value - 0 at the Item constructor.

  sql/item.h
    1.197 06/05/17 22:48:06 evgen@stripped +3 -0
    Fixed bug#19077: Too early applied subselect optimization leads to wrong
    result.
    New flag with_subselect is added to the Item class. It shows that expression
    which this item represents is a subselect or contains a subselect.
    It is set to 0 by default.

  sql/item_cmpfunc.cc
    1.201 06/05/17 22:44:36 evgen@stripped +21 -5
    Fixed bug#19077: Too early applied subselect optimization leads to wrong
    result.
    The convert_constant_item() function now doesn't convert a constant item
    with the with_subselect flag set. 
    The Item_cond::fix_fields() sets new with_subselect flag from with_subselect f
    lags of its arguments.

  sql/item_func.cc
    1.287 06/05/17 22:43:05 evgen@stripped +1 -0
    Fixed bug#19077: Too early applied subselect optimization leads to wrong
    result.
    
    The Item_func::fix_fields() sets new with_subselect flag from with_subselect flags of
its arguments.

  sql/item_subselect.cc
    1.125 06/05/17 22:42:05 evgen@stripped +1 -0
    Fixed bug#19077: Too early applied subselect optimization leads to wrong
    resultThe Item_subselect class constructor sets new with_subselect flag to 1.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	evgen
# Host:	moonbone.local
# Root:	/work/19077-bug-5.0-mysql

--- 1.222/sql/item.cc	2006-05-16 03:44:39 +04:00
+++ 1.223/sql/item.cc	2006-05-17 22:49:16 +04:00
@@ -304,6 +304,7 @@
   marker= 0;
   maybe_null=null_value=with_sum_func=unsigned_flag=0;
   decimals= 0; max_length= 0;
+  with_subselect= 0;
 
   /* Put item in free list so that we can free all items at end */
   THD *thd= current_thd;

--- 1.196/sql/item.h	2006-05-16 03:44:39 +04:00
+++ 1.197/sql/item.h	2006-05-17 22:48:06 +04:00
@@ -460,6 +460,9 @@
   my_bool is_autogenerated_name;        /* indicate was name of this Item
                                            autogenerated or set by user */
   DTCollation collation;
+  my_bool with_subselect;               /* If this item is a subselect or some
+                                           of its arguments is or contains a
+                                           subselect */
 
   // alloc & destruct is done as start of select using sql_alloc
   Item();

--- 1.200/sql/item_cmpfunc.cc	2006-04-25 01:50:25 +04:00
+++ 1.201/sql/item_cmpfunc.cc	2006-05-17 22:44:36 +04:00
@@ -204,10 +204,25 @@
 
 
 /*
-  Convert a constant expression or string to an integer.
-  This is done when comparing DATE's of different formats and
-  also when comparing bigint to strings (in which case the string
-  is converted once to a bigint).
+  Convert a constant item to an int and replace original item
+
+  SYNOPSIS
+    convert_constant_item()
+    thd             thread handle
+    field           item will be converted using this field
+    item  [in/out]  reference to the item to convert
+
+  DESCRIPTION
+    Convert a constant expression or string to an integer and
+    replace original item with new on successful conversion.
+    This is done when comparing DATE/TIME of different formats and
+    also when comparing bigint to strings (in which case the string
+    is converted once to a bigint).
+    This function should be used only on prepare phase.
+
+  NOTES
+    Due to the locking schema subselect items or items that contain
+    subselects can't be converted here.
 
   RESULT VALUES
   0	Can't convert item
@@ -216,7 +231,7 @@
 
 static bool convert_constant_item(THD *thd, Field *field, Item **item)
 {
-  if ((*item)->const_item())
+  if (!(*item)->with_subselect && (*item)->const_item())
   {
     /* For comparison purposes allow invalid dates like 2000-01-32 */
     ulong orig_sql_mode= field->table->in_use->variables.sql_mode;
@@ -2578,6 +2593,7 @@
       const_item_cache= FALSE;
     }  
     with_sum_func=	    with_sum_func || item->with_sum_func;
+    with_subselect|=        item->with_subselect;
     if (item->maybe_null)
       maybe_null=1;
   }

--- 1.286/sql/item_func.cc	2006-05-15 15:28:10 +04:00
+++ 1.287/sql/item_func.cc	2006-05-17 22:43:05 +04:00
@@ -184,6 +184,7 @@
       used_tables_cache|=     item->used_tables();
       not_null_tables_cache|= item->not_null_tables();
       const_item_cache&=      item->const_item();
+      with_subselect|=        item->with_subselect;
     }
   }
   fix_length_and_dec();

--- 1.124/sql/item_subselect.cc	2006-05-11 16:30:49 +04:00
+++ 1.125/sql/item_subselect.cc	2006-05-17 22:42:05 +04:00
@@ -39,6 +39,7 @@
   engine(0), old_engine(0), used_tables_cache(0), have_to_be_excluded(0),
   const_item_cache(1), engine_changed(0), changed(0)
 {
+  with_subselect= 1;
   reset();
   /*
     item value is NULL if select_subselect not changed this value