Merge bk-internal.mysql.com:/home/bk/mysql-4.1

into mysql.com:/home/my/mysql-4.1


sql/item_cmpfunc.cc:
  Auto merged
sql/item_func.cc:
  Auto merged

5 files changed, 65 insertions, 9 deletions

diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 46ef3281dd1..2b9a612da18 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -1964,6 +1964,36 @@ bool Item_cond::walk(Item_processor processor, byte *arg)
   return Item_func::walk(processor, arg);
 }
 
+
+/*
+  Move SUM items out from item tree and replace with reference
+
+  SYNOPSIS
+  split_sum_func()
+  thd			Thread handler
+  ref_pointer_array	Pointer to array of reference fields
+  fields		All fields in select
+
+  NOTES
+   This function is run on all expression (SELECT list, WHERE, HAVING etc)
+   that have or refer (HAVING) to a SUM expression.
+
+   The split is done to get an unique item for each SUM function
+   so that we can easily find and calculate them.
+   (Calculation done by update_sum_func() and copy_sum_funcs() in
+   sql_select.cc)
+
+   All found SUM items are added FIRST in the fields list and
+   we replace the item with a reference.
+
+   We also replace all functions without side effects (like RAND() or UDF's)
+   that uses columns as arguments.
+   For functions with side effects, we just remember any fields referred
+   by the function to ensure that we get a copy of the field value for the
+   first accepted row. This ensures that we can do things like
+   SELECT a*SUM(b) FROM t1 WHERE a=1
+*/
+
 void Item_cond::split_sum_func(THD *thd, Item **ref_pointer_array,
                                List<Item> &fields)
 {
@@ -1973,10 +2003,22 @@ void Item_cond::split_sum_func(THD *thd, Item **ref_pointer_array,
   const_item_cache=0;
   while ((item=li++))
   {
-    if (item->with_sum_func && item->type() != SUM_FUNC_ITEM)
+    /* with_sum_func is set for items that contains a SUM expression */
+    if (item->type() != SUM_FUNC_ITEM &&
+        (item->with_sum_func ||
+         (item->used_tables() & PSEUDO_TABLE_BITS)))
       item->split_sum_func(thd, ref_pointer_array, fields);
-    else if (item->used_tables() || item->type() == SUM_FUNC_ITEM)
+    else if (item->type() == SUM_FUNC_ITEM ||
+             (item->used_tables() && item->type() != REF_ITEM))
     {
+      /*
+        Replace item with a reference so that we can easily calculate
+        it (in case of sum functions) or copy it (in case of fields)
+
+        The test above is to ensure we don't do a reference for things
+        that are constants or are not yet calculated as in:
+        SELECT RAND() as r1, SUM(a) as r2 FROM t1 HAVING r1 > 1 AND r2 > 0
+      */
       Item **ref= li.ref();
       uint el= fields.elements;
       ref_pointer_array[el]= item;
diff --git a/sql/item_func.cc b/sql/item_func.cc
index f226603d9d1..d5d0ac8cd49 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -351,6 +351,7 @@ bool Item_func::walk (Item_processor processor, byte *argument)
   return (this->*processor)(argument);
 }
 
+
 void Item_func::split_sum_func(THD *thd, Item **ref_pointer_array,
                                List<Item> &fields)
 {
@@ -358,9 +359,12 @@ void Item_func::split_sum_func(THD *thd, Item **ref_pointer_array,
   for (arg= args, arg_end= args+arg_count; arg != arg_end ; arg++)
   {
     Item *item=* arg;
-    if (item->with_sum_func && item->type() != SUM_FUNC_ITEM)
+    if (item->type() != SUM_FUNC_ITEM &&
+        (item->with_sum_func ||
+         (item->used_tables() & PSEUDO_TABLE_BITS)))
       item->split_sum_func(thd, ref_pointer_array, fields);
-    else if (item->used_tables() || item->type() == SUM_FUNC_ITEM)
+    else if (item->type() == SUM_FUNC_ITEM ||
+             (item->used_tables() && item->type() != REF_ITEM))
     {
       uint el= fields.elements;
       ref_pointer_array[el]= item;
diff --git a/sql/item_row.cc b/sql/item_row.cc
index 4e4957b980e..0ace0fc0451 100644
--- a/sql/item_row.cc
+++ b/sql/item_row.cc
@@ -84,15 +84,20 @@ bool Item_row::fix_fields(THD *thd, TABLE_LIST *tabl, Item **ref)
   return 0;
 }
 
+
 void Item_row::split_sum_func(THD *thd, Item **ref_pointer_array,
                               List<Item> &fields)
 {
   Item **arg, **arg_end;
   for (arg= items, arg_end= items+arg_count; arg != arg_end ; arg++)
   {
-    if ((*arg)->with_sum_func && (*arg)->type() != SUM_FUNC_ITEM)
-      (*arg)->split_sum_func(thd, ref_pointer_array, fields);
-    else if ((*arg)->used_tables() || (*arg)->type() == SUM_FUNC_ITEM)
+    Item *item= *arg;
+    if (item->type() != SUM_FUNC_ITEM &&
+        (item->with_sum_func ||
+         (item->used_tables() & PSEUDO_TABLE_BITS)))
+      item->split_sum_func(thd, ref_pointer_array, fields);
+    else if (item->type() == SUM_FUNC_ITEM ||
+             (item->used_tables() && item->type() != REF_ITEM))
     {
       uint el= fields.elements;
       ref_pointer_array[el]=*arg;
diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc
index 1fb68561374..b22b65eddd0 100644
--- a/sql/item_strfunc.cc
+++ b/sql/item_strfunc.cc
@@ -1758,9 +1758,12 @@ String *Item_func_elt::val_str(String *str)
 void Item_func_make_set::split_sum_func(THD *thd, Item **ref_pointer_array,
 					List<Item> &fields)
 {
-  if (item->with_sum_func && item->type() != SUM_FUNC_ITEM)
+  if (item->type() != SUM_FUNC_ITEM &&
+      (item->with_sum_func ||
+       (item->used_tables() & PSEUDO_TABLE_BITS)))
     item->split_sum_func(thd, ref_pointer_array, fields);
-  else if (item->used_tables() || item->type() == SUM_FUNC_ITEM)
+  else if (item->type() == SUM_FUNC_ITEM ||
+           (item->used_tables() && item->type() != REF_ITEM))
   {
     uint el= fields.elements;
     ref_pointer_array[el]=item;
diff --git a/sql/unireg.h b/sql/unireg.h
index 4ab2ba26b15..70df9a89c8f 100644
--- a/sql/unireg.h
+++ b/sql/unireg.h
@@ -72,6 +72,8 @@
 #define PARAM_TABLE_BIT	(((table_map) 1) << (sizeof(table_map)*8-3))
 #define OUTER_REF_TABLE_BIT	(((table_map) 1) << (sizeof(table_map)*8-2))
 #define RAND_TABLE_BIT	(((table_map) 1) << (sizeof(table_map)*8-1))
+#define PSEUDO_TABLE_BITS (PARAM_TABLE_BIT | OUTER_REF_TABLE_BIT | \
+                           RAND_TABLE_BIT)
 #define MAX_FIELDS	4096			/* Limit in the .frm file */
 
 #define MAX_SORT_MEMORY (2048*1024-MALLOC_OVERHEAD)