Merge of fix for bug #2050 and bug #3307

BitKeeper/etc/logging_ok:
  auto-union
sql/item.cc:
  Auto merged
sql/item.h:
  Auto merged
sql/mysql_priv.h:
  Auto merged
sql/sql_acl.cc:
  Auto merged
sql/sql_base.cc:
  Manual merge

7 files changed, 120 insertions, 35 deletions

diff --git a/sql/item.cc b/sql/item.cc
index 48e35f06ec3..9cad60b8197 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -103,9 +103,12 @@ void Item::print_item_w_name(String *str)
 
 Item_ident::Item_ident(const char *db_name_par,const char *table_name_par,
 		       const char *field_name_par)
-  :changed_during_fix_field(0), db_name(db_name_par),
-   table_name(table_name_par), field_name(field_name_par),
-   depended_from(0)
+  :
+   orig_db_name(db_name_par), orig_table_name(table_name_par), 
+   orig_field_name(field_name_par), changed_during_fix_field(0), 
+   db_name(db_name_par), table_name(table_name_par), 
+   field_name(field_name_par), cached_field_index(NO_CACHED_FIELD_INDEX), 
+   cached_table(0), depended_from(0)
 {
   name = (char*) field_name_par;
 }
@@ -113,10 +116,15 @@ Item_ident::Item_ident(const char *db_name_par,const char *table_name_par,
 // Constructor used by Item_field & Item_ref (see Item comment)
 Item_ident::Item_ident(THD *thd, Item_ident *item)
   :Item(thd, item),
+   orig_db_name(item->orig_db_name),
+   orig_table_name(item->orig_table_name), 
+   orig_field_name(item->orig_field_name),
    changed_during_fix_field(0),
    db_name(item->db_name),
    table_name(item->table_name),
    field_name(item->field_name),
+   cached_field_index(item->cached_field_index),
+   cached_table(item->cached_table),
    depended_from(item->depended_from)
 {}
 
@@ -128,6 +136,9 @@ void Item_ident::cleanup()
     *changed_during_fix_field= this;
     changed_during_fix_field= 0;
   }
+  db_name= orig_db_name; 
+  table_name= orig_table_name;
+  field_name= orig_field_name;
 }
 
 bool Item_ident::remove_dependence_processor(byte * arg)
@@ -309,6 +320,15 @@ Item_field::Item_field(Field *f)
   fixed= 1;
 }
 
+Item_field::Item_field(THD *thd, Field *f)
+  :Item_ident(NullS, thd->strdup(f->table_name), 
+              thd->strdup(f->field_name))
+{
+  set_field(f);
+  collation.set(DERIVATION_IMPLICIT);
+  fixed= 1;
+}
+
 // Constructor need to process subselect with temporary tables (see Item)
 Item_field::Item_field(THD *thd, Item_field *item)
   :Item_ident(thd, item),
diff --git a/sql/item.h b/sql/item.h
index dffa93eaac8..902f42dd07c 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -257,15 +257,37 @@ public:
   virtual Item_num *neg()= 0;
 };
 
+#define NO_CACHED_FIELD_INDEX ((uint)(-1))
 
 class st_select_lex;
 class Item_ident :public Item
 {
+  /* 
+    We have to store initial values of db_name, table_name and field_name
+    to be able to restore them during cleanup() because they can be 
+    updated during fix_fields() to values from Field object and life-time 
+    of those is shorter than life-time of Item_field.
+  */
+  const char *orig_db_name;
+  const char *orig_table_name;
+  const char *orig_field_name;
   Item **changed_during_fix_field;
 public:
   const char *db_name;
   const char *table_name;
   const char *field_name;
+  /* 
+    Cached value of index for this field in table->field array, used by prep. 
+    stmts for speeding up their re-execution. Holds NO_CACHED_FIELD_INDEX 
+    if index value is not known.
+  */
+  uint cached_field_index;
+  /*
+    Cached pointer to table which contains this field, used for the same reason
+    by prep. stmt. too in case then we have not-fully qualified field.
+    0 - means no cached value.
+  */
+  TABLE_LIST *cached_table;
   st_select_lex *depended_from;
   Item_ident(const char *db_name_par,const char *table_name_par,
 	     const char *field_name_par);
@@ -297,6 +319,11 @@ public:
   { collation.set(DERIVATION_IMPLICIT); }
   // Constructor need to process subselect with temporary tables (see Item)
   Item_field(THD *thd, Item_field *item);
+  /*
+    Constructor used inside setup_wild(), ensures that field and table
+    names will live as long as Item_field (important in prep. stmt.)
+  */
+  Item_field(THD *thd, Field *field);
   Item_field(Field *field);
   enum Type type() const { return FIELD_ITEM; }
   bool eq(const Item *item, bool binary_cmp) const;
diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h
index bd919d12348..4fd41b7bd66 100644
--- a/sql/mysql_priv.h
+++ b/sql/mysql_priv.h
@@ -552,7 +552,8 @@ extern const Field *not_found_field;
 Field *find_field_in_tables(THD *thd, Item_ident *item, TABLE_LIST *tables,
 			    TABLE_LIST **where, bool report_error);
 Field *find_field_in_table(THD *thd,TABLE *table,const char *name,uint length,
-			   bool check_grant,bool allow_rowid);
+                           bool check_grant,bool allow_rowid,
+                           uint *cached_field_index_ptr);
 #ifdef HAVE_OPENSSL
 #include <openssl/des.h>
 struct st_des_keyblock
diff --git a/sql/sql_acl.cc b/sql/sql_acl.cc
index ef5036bb9f1..3add540f9a9 100644
--- a/sql/sql_acl.cc
+++ b/sql/sql_acl.cc
@@ -2194,8 +2194,10 @@ int mysql_table_grant(THD *thd, TABLE_LIST *table_list,
       DBUG_RETURN(-1);
     while ((column = column_iter++))
     {
+      uint unused_field_idx= NO_CACHED_FIELD_INDEX;
       if (!find_field_in_table(thd,table,column->column.ptr(),
-			       column->column.length(),0,0))
+                               column->column.length(),0,0,
+                               &unused_field_idx))
       {
 	my_error(ER_BAD_FIELD_ERROR, MYF(0),
                  column->column.c_ptr(), table_list->alias);
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index 60c2938ba4e..2b60a3b3e04 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -1793,33 +1793,42 @@ bool rm_temporary_table(enum db_type base, char *path)
 #define WRONG_GRANT (Field*) -1
 
 Field *find_field_in_table(THD *thd,TABLE *table,const char *name,uint length,
-			   bool check_grants, bool allow_rowid)
+                           bool check_grants, bool allow_rowid, 
+                           uint *cached_field_index_ptr)
 {
-  Field *field;
-  if (table->name_hash.records)
+  Field **field_ptr, *field;
+  uint cached_field_index= *cached_field_index_ptr;
+
+  /* We assume here that table->field < NO_CACHED_FIELD_INDEX = UINT_MAX */
+  if (cached_field_index < table->fields &&
+      !my_strcasecmp(system_charset_info, 
+                     table->field[cached_field_index]->field_name, name))
+      field_ptr= table->field + cached_field_index;
+  else if (table->name_hash.records)
+    field_ptr= (Field**)hash_search(&table->name_hash,(byte*) name,
+                                    length);
+  else
+  {
+    if (!(field_ptr= table->field))
+      return (Field *)0;
+    for (; *field_ptr; ++field_ptr)
+      if (!my_strcasecmp(system_charset_info, (*field_ptr)->field_name, name))
+        break;
+  }
+
+  if (field_ptr && *field_ptr)
   {
-    if ((field=(Field*) hash_search(&table->name_hash,(byte*) name,
-				    length)))
-      goto found;
+    *cached_field_index_ptr= field_ptr - table->field;
+    field= *field_ptr;
   }
   else
   {
-    Field **ptr;
-    if (!(ptr=table->field))
-      return (Field *)0;
-    while ((field = *ptr++))
-    {
-      if (!my_strcasecmp(system_charset_info, field->field_name, name))
-	goto found;
-    }
+    if (!allow_rowid ||
+        my_strcasecmp(system_charset_info, name, "_rowid") ||
+        !(field=table->rowid_field))
+      return (Field*) 0;
   }
-  if (allow_rowid &&
-      !my_strcasecmp(system_charset_info, name, "_rowid") &&
-      (field=table->rowid_field))
-    goto found;
-  return (Field*) 0;
 
- found:
   if (thd->set_query_id)
   {
     if (field->query_id != thd->query_id)
@@ -1874,6 +1883,31 @@ find_field_in_tables(THD *thd, Item_ident *item, TABLE_LIST *tables,
   uint length=(uint) strlen(name);
   char name_buff[NAME_LEN+1];
 
+
+  if (item->cached_table)
+  {
+    /*
+      This shortcut is used by prepared statements. We assuming that 
+      TABLE_LIST *tables is not changed during query execution (which 
+      is true for all queries except RENAME but luckily RENAME doesn't 
+      use fields...) so we can rely on reusing pointer to its member.
+      With this optimisation we also miss case when addition of one more
+      field makes some prepared query ambiguous and so erronous, but we 
+      accept this trade off.
+    */
+    found= find_field_in_table(thd,tables->table,name,length,
+                               test(tables->table->grant.want_privilege),
+                               1, &(item->cached_field_index));
+
+    if (found)
+    {
+      (*where)= tables;
+      if (found == WRONG_GRANT)
+        return (Field*) 0;
+      return found;
+    }
+  }
+
   if (db && lower_case_table_names)
   {
     /*
@@ -1898,10 +1932,10 @@ find_field_in_tables(THD *thd, Item_ident *item, TABLE_LIST *tables,
 	Field *find=find_field_in_table(thd,tables->table,name,length,
 					test(tables->table->grant.
 					     want_privilege),
-					1);
+					1, &(item->cached_field_index));
 	if (find)
 	{
-	  (*where)= tables;
+	  (*where)= item->cached_table= tables;
 	  if (find == WRONG_GRANT)
 	    return (Field*) 0;
 	  if (db || !thd->where)
@@ -1955,12 +1989,12 @@ find_field_in_tables(THD *thd, Item_ident *item, TABLE_LIST *tables,
 
     Field *field=find_field_in_table(thd,tables->table,name,length,
 				     test(tables->table->grant.want_privilege),
-				     allow_rowid);
+				     allow_rowid, &(item->cached_field_index));
     if (field)
     {
       if (field == WRONG_GRANT)
 	return (Field*) 0;
-      (*where)= tables;
+      (*where)= item->cached_table= tables;
       if (found)
       {
 	if (!thd->where)			// Returns first found
@@ -2308,7 +2342,7 @@ insert_fields(THD *thd,TABLE_LIST *tables, const char *db_name,
             !find_field_in_table(thd, natural_join_table, field->field_name, 
                                  strlen(field->field_name), 0, 0))
         {
-          Item_field *item= new Item_field(field);
+          Item_field *item= new Item_field(thd, field);
           if (!found++)
             (void) it->replace(item);		// Replace '*'
           else
diff --git a/sql/table.cc b/sql/table.cc
index 526810de74a..dcd0d39d855 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -30,11 +30,11 @@ static void fix_type_pointers(const char ***array, TYPELIB *point_to_type,
 static uint find_field(TABLE *form,uint start,uint length);
 
 
-static byte* get_field_name(Field *buff,uint *length,
+static byte* get_field_name(Field **buff,uint *length,
 			    my_bool not_used __attribute__((unused)))
 {
-  *length= (uint) strlen(buff->field_name);
-  return (byte*) buff->field_name;
+  *length= (uint) strlen((*buff)->field_name);
+  return (byte*) (*buff)->field_name;
 }
 
 /*
@@ -479,7 +479,7 @@ int openfrm(const char *name, const char *alias, uint db_stat, uint prgflag,
     if (outparam->timestamp_field == reg_field)
       outparam->timestamp_field_offset=i;
     if (use_hash)
-      (void) my_hash_insert(&outparam->name_hash,(byte*) *field_ptr); // Will never fail
+      (void) my_hash_insert(&outparam->name_hash,(byte*) field_ptr); // Will never fail
   }
   *field_ptr=0;					// End marker
 
diff --git a/sql/table.h b/sql/table.h
index c027e2ccc44..039e3ded9f3 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -65,7 +65,8 @@ struct st_table {
   handler *file;
   Field **field;			/* Pointer to fields */
   Field_blob **blob_field;		/* Pointer to blob fields */
-  HASH	name_hash;			/* hash of field names */
+  /* hash of field names (contains pointers to elements of field array) */
+  HASH	name_hash;
   byte *record[2];			/* Pointer to records */
   byte *default_values;          	/* Default values for INSERT */
   byte *insert_values;                  /* used by INSERT ... UPDATE */