Don't automaticly generate a new key for a foreign key constraint if there is already a usable key.

Prefer not automatic keys before automatic keys. If there is two conf


BitKeeper/etc/ignore:
  added *.d
include/my_base.h:
  Added flag for automaticly generated key
mysql-test/r/constraints.result:
  Update tests after bug fix
mysql-test/r/create.result:
  Update tests after bug fix
mysql-test/r/innodb.result:
  Added test of automatic creation of foreign keys
mysql-test/t/innodb.test:
  Added test of automatic creation of foreign keys
mysql-test/t/key_cache.test:
  Portability fixes (64 BIT os)
sql/sql_acl.cc:
  Indentation fixes
sql/sql_class.cc:
  Fix key comparison to handle prefix and optionally key segments in different order.
sql/sql_class.h:
  Added flag for automaticly generated keys
sql/sql_parse.cc:
  Added flag for automaticly generated keys
sql/sql_table.cc:
  Don't automaticly generate a new key for a foreign key constraint if there is already a usable key.
  Prefer not automatic keys before automatic keys. If there is two conflicting automatic keys, prefer the longer one.
sql/sql_yacc.yy:
  Added flag for automaticly generated keys
strings/strings-x86.s:
  Portability fix.

6 files changed, 108 insertions, 40 deletions

diff --git a/sql/sql_acl.cc b/sql/sql_acl.cc
index b2d030b523d..9c7fe3e2993 100644
--- a/sql/sql_acl.cc
+++ b/sql/sql_acl.cc
@@ -1918,7 +1918,8 @@ static int replace_column_table(GRANT_TABLE *g_t,
     ulong privileges = xx->rights;
     bool old_row_exists=0;
     key_restore(table,key,0,key_length);
-    table->field[4]->store(xx->column.ptr(),xx->column.length(),&my_charset_latin1);
+    table->field[4]->store(xx->column.ptr(),xx->column.length(),
+                           &my_charset_latin1);
 
     if (table->file->index_read(table->record[0],(byte*) table->field[0]->ptr,
 				0, HA_READ_KEY_EXACT))
@@ -1931,9 +1932,10 @@ static int replace_column_table(GRANT_TABLE *g_t,
 	continue; /* purecov: inspected */
       }
       old_row_exists = 0;
-      restore_record(table,default_values);				// Get empty record
+      restore_record(table,default_values);		// Get empty record
       key_restore(table,key,0,key_length);
-      table->field[4]->store(xx->column.ptr(),xx->column.length(), &my_charset_latin1);
+      table->field[4]->store(xx->column.ptr(),xx->column.length(),
+                             &my_charset_latin1);
     }
     else
     {
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index f297ddf2917..03d67c4f300 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -84,26 +84,71 @@ bool key_part_spec::operator==(const key_part_spec& other) const
   return length == other.length && !strcmp(field_name, other.field_name);
 }
 
-/* Equality comparison of keys (ignoring name) */
-bool Key::operator==(Key& other)
+
+/*
+  Test if a foreign key is a prefix of the given key
+  (ignoring key name, key type and order of columns)
+
+  NOTES:
+    This is only used to test if an index for a FOREIGN KEY exists
+
+  IMPLEMENTATION
+    We only compare field names
+
+  RETURN
+    0	Generated key is a prefix of other key
+    1	Not equal
+*/
+
+bool foreign_key_prefix(Key *a, Key *b)
 {
-  if (type == other.type &&
-      algorithm == other.algorithm &&
-      columns.elements == other.columns.elements)
+  /* Ensure that 'a' is the generated key */
+  if (a->generated)
+  {
+    if (b->generated && a->columns.elements > b->columns.elements)
+      swap(Key*, a, b);                          // Put shorter key in 'a'
+  }
+  else
   {
-    List_iterator<key_part_spec> col_it1(columns);
-    List_iterator<key_part_spec> col_it2(other.columns);
-    const key_part_spec *col1, *col2;
-    while ((col1 = col_it1++))
+    if (!b->generated)
+      return TRUE;                              // No foreign key
+    swap(Key*, a, b);                           // Put generated key in 'a'
+  }
+
+  /* Test if 'a' is a prefix of 'b' */
+  if (a->columns.elements > b->columns.elements)
+    return TRUE;                                // Can't be prefix
+
+  List_iterator<key_part_spec> col_it1(a->columns);
+  List_iterator<key_part_spec> col_it2(b->columns);
+  const key_part_spec *col1, *col2;
+
+#ifdef ENABLE_WHEN_INNODB_CAN_HANDLE_SWAPED_FOREIGN_KEY_COLUMNS
+  while ((col1= col_it1++))
+  {
+    bool found= 0;
+    col_it2.rewind();
+    while ((col2= col_it2++))
     {
-      col2 = col_it2++;
-      DBUG_ASSERT(col2 != NULL);
-      if (!(*col1 == *col2))
-	return false;
+      if (*col1 == *col2)
+      {
+        found= TRUE;
+	break;
+      }
     }
-    return true;
+    if (!found)
+      return TRUE;                              // Error
+  }
+  return FALSE;                                 // Is prefix
+#else
+  while ((col1= col_it1++))
+  {
+    col2= col_it2++;
+    if (!(*col1 == *col2))
+      return TRUE;
   }
-  return false;
+  return FALSE;                                 // Is prefix
+#endif
 }
 
 
diff --git a/sql/sql_class.h b/sql/sql_class.h
index a2094d8fe7c..e602b7d6d5f 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -240,14 +240,16 @@ public:
   enum ha_key_alg algorithm;
   List<key_part_spec> columns;
   const char *name;
+  bool generated;
 
   Key(enum Keytype type_par, const char *name_arg, enum ha_key_alg alg_par,
-      List<key_part_spec> &cols)
-    :type(type_par), algorithm(alg_par), columns(cols), name(name_arg)
+      bool generated_arg, List<key_part_spec> &cols)
+    :type(type_par), algorithm(alg_par), columns(cols), name(name_arg),
+    generated(generated_arg)
   {}
   ~Key() {}
   /* Equality comparison of keys (ignoring name) */
-  bool operator==(Key& other);
+  friend bool foreign_key_prefix(Key *a, Key *b);
 };
 
 class Table_ident;
@@ -265,7 +267,7 @@ public:
   foreign_key(const char *name_arg, List<key_part_spec> &cols,
 	      Table_ident *table,   List<key_part_spec> &ref_cols,
 	      uint delete_opt_arg, uint update_opt_arg, uint match_opt_arg)
-    :Key(FOREIGN_KEY, name_arg, HA_KEY_ALG_UNDEF, cols),
+    :Key(FOREIGN_KEY, name_arg, HA_KEY_ALG_UNDEF, 0, cols),
     ref_table(table), ref_columns(cols),
     delete_opt(delete_opt_arg), update_opt(update_opt_arg),
     match_opt(match_opt_arg)
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 98f6a12ec64..e949d40625d 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -3958,13 +3958,13 @@ bool add_field_to_list(THD *thd, char *field_name, enum_field_types type,
   {
     lex->col_list.push_back(new key_part_spec(field_name,0));
     lex->key_list.push_back(new Key(Key::PRIMARY, NullS, HA_KEY_ALG_UNDEF,
-				    lex->col_list));
+				    0, lex->col_list));
     lex->col_list.empty();
   }
   if (type_modifier & (UNIQUE_FLAG | UNIQUE_KEY_FLAG))
   {
     lex->col_list.push_back(new key_part_spec(field_name,0));
-    lex->key_list.push_back(new Key(Key::UNIQUE, NullS, HA_KEY_ALG_UNDEF,
+    lex->key_list.push_back(new Key(Key::UNIQUE, NullS, HA_KEY_ALG_UNDEF, 0,
 				    lex->col_list));
     lex->col_list.empty();
   }
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 55b726293c2..b90ff942cc6 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -679,14 +679,27 @@ int mysql_prepare_table(THD *thd, HA_CREATE_INFO *create_info,
       DBUG_RETURN(-1);
     }
     key_iterator2.rewind ();
-    while ((key2 = key_iterator2++) != key)
+    if (key->type != Key::FOREIGN_KEY)
     {
-      if (*key == *key2)
+      while ((key2 = key_iterator2++) != key)
       {
-	/* TO DO: issue warning message */
-	/* mark that the key should be ignored */
-	key->name=ignore_key;
-	break;
+        if ((key2->type != Key::FOREIGN_KEY && !foreign_key_prefix(key, key2)))
+        {
+          /* TO DO: issue warning message */
+          /* mark that the generated key should be ignored */
+          if (!key2->generated ||
+              (key->generated && key->columns.elements <
+               key2->columns.elements))
+            key->name= ignore_key;
+          else
+          {
+            /* Remove the previous, generated key */
+            key2->name= ignore_key;
+            key_parts-= key2->columns.elements;
+            (*key_count)--;
+          }
+          break;
+        }
       }
     }
     if (key->name != ignore_key)
@@ -731,14 +744,14 @@ int mysql_prepare_table(THD *thd, HA_CREATE_INFO *create_info,
 
     switch(key->type){
     case Key::MULTIPLE:
-	key_info->flags = 0;
+	key_info->flags= 0;
 	break;
     case Key::FULLTEXT:
-	key_info->flags = HA_FULLTEXT;
+	key_info->flags= HA_FULLTEXT;
 	break;
     case Key::SPATIAL:
 #ifdef HAVE_SPATIAL
-	key_info->flags = HA_SPATIAL;
+	key_info->flags= HA_SPATIAL;
 	break;
 #else
 	my_printf_error(ER_FEATURE_DISABLED,ER(ER_FEATURE_DISABLED),MYF(0),
@@ -749,8 +762,11 @@ int mysql_prepare_table(THD *thd, HA_CREATE_INFO *create_info,
       key_number--;				// Skip this key
       continue;
     default:
-	key_info->flags = HA_NOSAME;
+      key_info->flags = HA_NOSAME;
+      break;
     }
+    if (key->generated)
+      key_info->flags|= HA_GENERATED_KEY;
 
     key_info->key_parts=(uint8) key->columns.elements;
     key_info->key_part=key_part_info;
@@ -774,7 +790,7 @@ int mysql_prepare_table(THD *thd, HA_CREATE_INFO *create_info,
     */
 
     /* TODO: Add proper checks if handler supports key_type and algorithm */
-    if (key_info->flags == HA_SPATIAL)
+    if (key_info->flags & HA_SPATIAL)
     {
       if (key_info->key_parts != 1)
       {
@@ -2824,6 +2840,7 @@ int mysql_alter_table(THD *thd,char *new_db, char *new_name,
 				   Key::FULLTEXT : Key::MULTIPLE)),
 				 key_name,
 				 key_info->algorithm,
+                                 test(key_info->flags & HA_GENERATED_KEY),
 				 key_parts));
   }
   {
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index 0693d33c781..25344fe84cd 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -955,7 +955,7 @@ create:
 	  {
 	    LEX *lex=Lex;
 
-	    lex->key_list.push_back(new Key($2,$4.str, $5, lex->col_list));
+	    lex->key_list.push_back(new Key($2,$4.str, $5, 0, lex->col_list));
 	    lex->col_list.empty();
 	  }
 	| CREATE DATABASE opt_if_not_exists ident
@@ -1187,14 +1187,15 @@ key_def:
 	key_type opt_ident key_alg '(' key_list ')'
 	  {
 	    LEX *lex=Lex;
-	    lex->key_list.push_back(new Key($1,$2, $3, lex->col_list));
+	    lex->key_list.push_back(new Key($1,$2, $3, 0, lex->col_list));
 	    lex->col_list.empty();		/* Alloced by sql_alloc */
 	  }
 	| opt_constraint constraint_key_type opt_ident key_alg '(' key_list ')'
 	  {
 	    LEX *lex=Lex;
 	    const char *key_name= $3 ? $3:$1;
-	    lex->key_list.push_back(new Key($2, key_name, $4, lex->col_list));
+	    lex->key_list.push_back(new Key($2, key_name, $4, 0,
+				    lex->col_list));
 	    lex->col_list.empty();		/* Alloced by sql_alloc */
 	  }
 	| opt_constraint FOREIGN KEY_SYM opt_ident '(' key_list ')' references
@@ -1206,8 +1207,9 @@ key_def:
 				    lex->fk_delete_opt,
 				    lex->fk_update_opt,
 				    lex->fk_match_option));
-	    lex->key_list.push_back(new Key(Key::MULTIPLE, $4 ? $4:$1,
-					    HA_KEY_ALG_UNDEF, lex->col_list));
+	    lex->key_list.push_back(new Key(Key::MULTIPLE, $4 ? $4 : $1,
+					    HA_KEY_ALG_UNDEF, 1,
+					    lex->col_list));
 	    lex->col_list.empty();		/* Alloced by sql_alloc */
 	  }
 	| constraint opt_check_constraint