ALTER TABLE ... DISABLE KEYS / ALTER TABLE ... ENABLE KEYS

Docs/manual.texi

@@ -19022,6 +19022,8 @@ alter_specification:
   or    DROP [COLUMN] col_name
   or    DROP PRIMARY KEY
   or    DROP INDEX index_name
+  or    DISABLE KEYS
+  or    ENABLE KEYS
   or    RENAME [TO] new_tbl_name
   or    ORDER BY col
   or    table_options
@@ -19183,6 +19185,15 @@ If you use @code{ALTER TABLE} on a @code{MyISAM} table, all non-unique
 indexes are created in a separate batch (like in @code{REPAIR}).
 This should make @code{ALTER TABLE} much faster when you have many indexes.
 
+@item
+Since @strong{MySQL 4.0} this feature could be activated explicitly.
+@code{ALTER TABLE ... DISABLE KEYS} makes @strong{MySQL} to stop updating
+non-unique indexes for @code{MyISAM} table.
+@code{ALTER TABLE ... ENABLE KEYS} then should be used to recreate missing
+indexes. As @strong{MySQL} does it with special algorithm which is much
+faster then inserting keys one by one, disabling keys could give a
+considerable speedup on bulk inserts.
+
 @item
 @findex mysql_info()
 With the C API function @code{mysql_info()}, you can find out how many
@@ -24645,14 +24656,11 @@ InnoDB: Database physically writes the file full: wait...
 InnoDB: Data file /home/heikki/data/ibdata2 did not exist: new to be created
 InnoDB: Setting file /home/heikki/data/ibdata2 size to 262144000
 InnoDB: Database physically writes the file full: wait...
-InnoDB: Log file /home/heikki/data/logs/ib_logfile0 did not exist: new to be c
-reated
+InnoDB: Log file /home/heikki/data/logs/ib_logfile0 did not exist: new to be created
 InnoDB: Setting log file /home/heikki/data/logs/ib_logfile0 size to 5242880
-InnoDB: Log file /home/heikki/data/logs/ib_logfile1 did not exist: new to be c
-reated
+InnoDB: Log file /home/heikki/data/logs/ib_logfile1 did not exist: new to be created
 InnoDB: Setting log file /home/heikki/data/logs/ib_logfile1 size to 5242880
-InnoDB: Log file /home/heikki/data/logs/ib_logfile2 did not exist: new to be c
-reated
+InnoDB: Log file /home/heikki/data/logs/ib_logfile2 did not exist: new to be created
 InnoDB: Setting log file /home/heikki/data/logs/ib_logfile2 size to 5242880
 InnoDB: Started
 mysqld: ready for connections
@@ -30936,8 +30944,13 @@ Execute a @code{FLUSH TABLES} statement or the shell command @code{mysqladmin
 flush-tables}.
 @end enumerate
 
-This procedure will be built into @code{LOAD DATA INFILE} in some future
-version of @strong{MySQL}.
+Since @strong{MySQL 4.0} you can also use
+@code{ALTER TABLE tbl_name DISABLE KEYS} instead of
+@code{myisamchk --keys-used=0 -rq /path/to/db/tbl_name} and
+@code{ALTER TABLE tbl_name ENABLE KEYS} instead of
+@code{myisamchk -r -q /path/to/db/tbl_name}. This way you can also skip
+@code{FLUSH TABLES} steps.
+
 @item
 You can speed up insertions by locking your tables:
 
@@ -43868,6 +43881,9 @@ Our TODO section contains what we plan to have in 4.0. @xref{TODO MySQL 4.0}.
 
 @itemize @bullet
 @item
+Added @code{ALTER TABLE table_name DISABLE KEYS} and
+      @code{ALTER TABLE table_name ENABLE KEYS} commands.
+@item
 Added @code{HANDLER} command.
 @item
 Added @code{SQL_CALC_FOUND_ROWS} and @code{FOUND_ROWS()}. This make it

mysql-test/t/alter_table.test

@@ -71,3 +71,23 @@ ALTER TABLE t1 ADD Column new_col int not null;
 UNLOCK TABLES;
 OPTIMIZE TABLE t1;
 DROP TABLE t1;
+drop table if exists t1;
+
+#
+# ALTER TABLE ... ENABLE/DISABLE KEYS
+
+create table t1 (n1 int not null, n2 int, n3 int, n4 float,
+                unique(n1),
+                key (n1, n2, n3, n4),
+                key (n2, n3, n4, n1),
+                key (n3, n4, n1, n2),
+                key (n4, n1, n2, n3) );
+alter table t1 disable keys;
+let $1=10000;
+while ($1)
+{
+ eval insert into t1 values($1,RAND()*1000,RAND()*1000,RAND());
+ dec $1;
+}
+alter table t1 enable keys;
+drop table t1;

sql/lex.h

@@ -112,6 +112,7 @@ static SYMBOL symbols[] = {
   { "DELETE",		SYM(DELETE_SYM),0,0},
   { "DESC",		SYM(DESC),0,0},
   { "DESCRIBE",		SYM(DESCRIBE),0,0},
+  { "DISABLE",		SYM(DISABLE_SYM),0,0},
   { "DISTINCT",		SYM(DISTINCT),0,0},
   { "DISTINCTROW",	SYM(DISTINCT),0,0},	/* Access likes this */
   { "DOUBLE",		SYM(DOUBLE_SYM),0,0},
@@ -122,6 +123,7 @@ static SYMBOL symbols[] = {
   { "ELSE",             SYM(ELSE),0,0},
   { "ESCAPE",		SYM(ESCAPE_SYM),0,0},
   { "ESCAPED",		SYM(ESCAPED),0,0},
+  { "ENABLE",		SYM(ENABLE_SYM),0,0},
   { "ENCLOSED",		SYM(ENCLOSED),0,0},
   { "ENUM",		SYM(ENUM),0,0},
   { "EXPLAIN",		SYM(DESCRIBE),0,0},

sql/mysql_priv.h

@@ -328,7 +328,9 @@ int mysql_alter_table(THD *thd, char *new_db, char *new_name,
 		      List<Alter_column> &alter_list,
                       ORDER *order,
 		      bool drop_primary,
-		      enum enum_duplicates handle_duplicates);
+		      enum enum_duplicates handle_duplicates,
+		      enum enum_enable_or_disable keys_onoff=LEAVE_AS_IS,
+    		      bool simple_alter=0);
 bool mysql_rename_table(enum db_type base,
 			const char *old_db,
 			const char * old_name,

sql/sql_class.h

@@ -24,6 +24,7 @@
 class Query_log_event;
 class Load_log_event;
 
+enum enum_enable_or_disable { LEAVE_AS_IS, ENABLE, DISABLE };
 enum enum_ha_read_modes { RFIRST, RNEXT, RPREV, RLAST, RKEY };
 enum enum_duplicates { DUP_ERROR, DUP_REPLACE, DUP_IGNORE };
 enum enum_log_type { LOG_CLOSED, LOG_NORMAL, LOG_NEW, LOG_BIN };

sql/sql_lex.h

@@ -144,10 +144,11 @@ typedef struct st_lex {
   enum enum_tx_isolation tx_isolation;
   enum enum_ha_read_modes ha_read_mode;
   enum ha_rkey_function ha_rkey_mode;
+  enum enum_enable_or_disable alter_keys_onoff;
   uint in_sum_expr,grant,grant_tot_col,which_columns, sort_default;
   thr_lock_type lock_option;
   bool	create_refs,drop_primary,drop_if_exists,local_file;
-  bool  in_comment,ignore_space,verbose;
+  bool  in_comment,ignore_space,verbose,simple_alter;
 
 } LEX;
 

sql/sql_parse.cc

@@ -1393,7 +1393,8 @@ mysql_execute_command(void)
 			       tables, lex->create_list,
 			       lex->key_list, lex->drop_list, lex->alter_list,
                                (ORDER *) lex->order_list.first,
-			       lex->drop_primary, lex->duplicates);
+			       lex->drop_primary, lex->duplicates,
+			       lex->alter_keys_onoff, lex->simple_alter);
       break;
     }
 #endif

sql/sql_table.cc

@@ -1080,7 +1080,9 @@ int mysql_alter_table(THD *thd,char *new_db, char *new_name,
 		      List<Alter_column> &alter_list,
                       ORDER *order,
 		      bool drop_primary,
-		      enum enum_duplicates handle_duplicates)
+		      enum enum_duplicates handle_duplicates,
+       		      enum enum_enable_or_disable keys_onoff,
+                      bool simple_alter)
 {
   TABLE *table,*new_table;
   int error;
@@ -1145,14 +1147,13 @@ int mysql_alter_table(THD *thd,char *new_db, char *new_name,
   if (create_info->row_type == ROW_TYPE_DEFAULT)
     create_info->row_type=table->row_type;
 
-  /* Check if the user only wants to do a simple RENAME */
+  /* In some simple cases we need not to recreate the table */
 
   thd->proc_info="setup";
-  if (new_name != table_name &&
-      !fields.elements && !keys.elements && ! drop_list.elements &&
-      !alter_list.elements && !drop_primary &&
-      new_db_type == old_db_type && create_info->max_rows == 0 &&
-      create_info->auto_increment_value == 0 && !table->tmp_table)
+  if (simple_alter)
+  {
+    error=0;
+    if (new_name != table_name)
     {
       thd->proc_info="rename";
       VOID(pthread_mutex_lock(&LOCK_open));
@@ -1178,6 +1179,18 @@ int mysql_alter_table(THD *thd,char *new_db, char *new_name,
 
       VOID(pthread_cond_broadcast(&COND_refresh));
       VOID(pthread_mutex_unlock(&LOCK_open));
+    }
+    if (!error)
+    {
+      switch (keys_onoff)
+      {
+        case LEAVE_AS_IS: break;
+        case ENABLE: error=table->file->activate_all_index(thd); break;
+        case DISABLE:
+          table->file->deactivate_non_unique_index(table->file->records);
+          break;
+      }
+    }
     if (!error)
     {
       mysql_update_log.write(thd, thd->query, thd->query_length);
@@ -1188,7 +1201,6 @@ int mysql_alter_table(THD *thd,char *new_db, char *new_name,
       }
       send_ok(&thd->net);
     }
-
     DBUG_RETURN(error);
   }
 

sql/sql_yacc.yy

@@ -145,12 +145,14 @@ bool my_yyoverflow(short **a, YYSTYPE **b,int *yystacksize);
 %token	DESC
 %token	DESCRIBE
 %token	DISTINCT
+%token	DISABLE_SYM
 %token	DOUBLE_SYM
 %token	DROP
 %token	DUMPFILE
 %token	DYNAMIC_SYM
 %token	ELSE
 %token	ELT_FUNC
+%token	ENABLE_SYM
 %token	ENCLOSED
 %token	ENCODE_SYM
 %token	ENCRYPT
@@ -1110,6 +1112,8 @@ alter:
 	  lex->db=lex->name=0;
     	  bzero((char*) &lex->create_info,sizeof(lex->create_info));
 	  lex->create_info.db_type= DB_TYPE_DEFAULT;
+          lex->alter_keys_onoff=LEAVE_AS_IS;
+          lex->simple_alter=1;
 	}
 	alter_list
  
@@ -1118,16 +1122,18 @@ alter_list:
 	| alter_list ',' alter_list_item
 
 add_column:
-	ADD opt_column { Lex->change=0;}
+	ADD opt_column { Lex->change=0; }
 
 alter_list_item:
-	add_column field_list_item opt_place
-	| add_column '(' field_list ')'
-	| CHANGE opt_column field_ident { Lex->change= $3.str; } field_spec
+	add_column field_list_item opt_place { Lex->simple_alter=0; }
+	| add_column '(' field_list ')'      { Lex->simple_alter=0; }
+	| CHANGE opt_column field_ident { Lex->change= $3.str; Lex->simple_alter=0; }
+          field_spec
 	| MODIFY_SYM opt_column field_ident
 	  {
 	    Lex->length=Lex->dec=0; Lex->type=0; Lex->interval=0;
 	    Lex->default_value=0;
+            Lex->simple_alter=0;
 	  }
 	  type opt_attribute
 	  {
@@ -1137,23 +1143,26 @@ alter_list_item:
 				  Lex->default_value, $3.str,
 				  Lex->interval))
 	     YYABORT;
+             Lex->simple_alter=0;
 	  }
 	| DROP opt_column field_ident opt_restrict
 	  { Lex->drop_list.push_back(new Alter_drop(Alter_drop::COLUMN,
-						    $3.str)); }
-	| DROP PRIMARY_SYM KEY_SYM { Lex->drop_primary=1; }
-	| DROP FOREIGN KEY_SYM opt_ident {}
+					    $3.str)); Lex->simple_alter=0; }
+	| DROP PRIMARY_SYM KEY_SYM { Lex->drop_primary=1; Lex->simple_alter=0; }
+	| DROP FOREIGN KEY_SYM opt_ident { Lex->simple_alter=0; }
 	| DROP key_or_index field_ident
 	  { Lex->drop_list.push_back(new Alter_drop(Alter_drop::KEY,
-						    $3.str)); }
+					    $3.str)); Lex->simple_alter=0; }
+	| DISABLE_SYM KEYS { Lex->alter_keys_onoff=DISABLE; }
+	| ENABLE_SYM KEYS  { Lex->alter_keys_onoff=ENABLE; }
 	| ALTER opt_column field_ident SET DEFAULT literal
-	  { Lex->alter_list.push_back(new Alter_column($3.str,$6)); }
+	  { Lex->alter_list.push_back(new Alter_column($3.str,$6)); Lex->simple_alter=0; }
 	| ALTER opt_column field_ident DROP DEFAULT
-	  { Lex->alter_list.push_back(new Alter_column($3.str,(Item*) 0)); }
+	  { Lex->alter_list.push_back(new Alter_column($3.str,(Item*) 0)); Lex->simple_alter=0; }
 	| RENAME opt_to table_alias table_ident
-	  { Lex->db=$4->db.str ; Lex->name= $4->table.str; }
-        | create_table_options
-	| order_clause
+	  { Lex->db=$4->db.str ; Lex->name= $4->table.str; Lex->simple_alter=0; }
+        | create_table_options { Lex->simple_alter=0; }
+	| order_clause         { Lex->simple_alter=0; }
 
 opt_column:
 	/* empty */	{}
@@ -2604,8 +2613,10 @@ keyword:
 	| DATE_SYM		{}
 	| DAY_SYM		{}
 	| DELAY_KEY_WRITE_SYM	{}
+        | DISABLE_SYM           {}
 	| DUMPFILE		{}
 	| DYNAMIC_SYM		{}
+        | ENABLE_SYM            {}
 	| END			{}
 	| ENUM			{}
 	| ESCAPE_SYM		{}