AUTO_INCREMENT support for MERGE

HA_AUTO_PART_KEY support for handler parent class

Docs/manual.texi

@@ -37793,8 +37793,8 @@ The disadvantages with @code{MERGE} tables are:
 @itemize @bullet
 @item
 You can only use identical @code{MyISAM} tables for a @code{MERGE} table.
-@item
-@code{AUTO_INCREMENT} columns are not automatically updated on @code{INSERT}.
+@c @item
+@c @code{AUTO_INCREMENT} columns are not automatically updated on @code{INSERT}.
 @item
 @code{REPLACE} doesn't work.
 @item
@@ -37834,13 +37834,13 @@ CREATE TABLE t1 (a INT AUTO_INCREMENT PRIMARY KEY, message CHAR(20));
 CREATE TABLE t2 (a INT AUTO_INCREMENT PRIMARY KEY, message CHAR(20));
 INSERT INTO t1 (message) VALUES ("Testing"),("table"),("t1");
 INSERT INTO t2 (message) VALUES ("Testing"),("table"),("t2");
-CREATE TABLE total (a INT NOT NULL, message CHAR(20), KEY(a))
+CREATE TABLE total (a INT AUTO_INCREMENT PRIMARY KEY, message CHAR(20))
              TYPE=MERGE UNION=(t1,t2) INSERT_METHOD=LAST;
 @end example
 
-Note that we didn't create a @code{UNIQUE} or @code{PRIMARY KEY} in the
-@code{total} table as the key isn't going to be unique in the @code{total}
-table.
+@c Note that we didn't create a @code{UNIQUE} or @code{PRIMARY KEY} in the
+@c @code{total} table as the key isn't going to be unique in the @code{total}
+@c table.
 
 Note that you can also manipulate the @file{.MRG} file directly from
 the outside of the MySQL server:
@@ -37867,6 +37867,10 @@ mysql> SELECT * FROM total;
 +---+---------+
 @end example
 
+Note that the @code{a} column, though declared as @code{PRIMARY KEY},
+is not really unique, as @code{MERGE} table cannot enforce uniqueness
+over a set of underlying @code{MyISAM} tables.
+
 To remap a @code{MERGE} table you can do one of the following:
 
 @itemize @bullet
@@ -37894,8 +37898,8 @@ The following are the known problems with @code{MERGE} tables:
 A @code{MERGE} table cannot maintain @code{UNIQUE} constraints over the
 whole table.  When you do @code{INSERT}, the data goes into the first or
 last table (according to @code{INSERT_METHOD=xxx}) and this @code{MyISAM}
-table ensures that the data are unique, but it knows nothing about the
-first @code{MyISAM} table.
+table ensures that the data are unique, but it knows nothing about
+others @code{MyISAM} tables.
 @item
 @code{DELETE FROM merge_table} used without a @code{WHERE}
 will only clear the mapping for the table, not delete everything in the
@@ -49699,6 +49703,8 @@ Our TODO section contains what we plan to have in 4.0. @xref{TODO MySQL 4.0}.
 @itemize @bullet
 @item
 Fixed a bug that made the pager option in the mysql client non-functional.
+@item
+Added full @code{AUTO_INCREMENT} support to @code{MERGE} tables.
 @end itemize
 
 

mysql-test/r/merge.result

@@ -275,12 +275,12 @@ a	b
 1	2
 drop table t3,t1,t2;
 drop table if exists t6, t5, t4, t3, t2, t1;
-create table t1 (a int not null, b int not null, key(a,b));
-create table t2 (a int not null, b int not null, key(a,b));
+create table t1 (a int not null, b int not null auto_increment, primary key(a,b));
+create table t2 (a int not null, b int not null auto_increment, primary key(a,b));
 create table t3 (a int not null, b int not null, key(a,b)) UNION=(t1,t2) INSERT_METHOD=NO;
 create table t4 (a int not null, b int not null, key(a,b)) TYPE=MERGE UNION=(t1,t2) INSERT_METHOD=NO;
-create table t5 (a int not null, b int not null, key(a,b)) TYPE=MERGE UNION=(t1,t2) INSERT_METHOD=FIRST;
-create table t6 (a int not null, b int not null, key(a,b)) TYPE=MERGE UNION=(t1,t2) INSERT_METHOD=LAST;
+create table t5 (a int not null, b int not null auto_increment, primary key(a,b)) TYPE=MERGE UNION=(t1,t2) INSERT_METHOD=FIRST;
+create table t6 (a int not null, b int not null auto_increment, primary key(a,b)) TYPE=MERGE UNION=(t1,t2) INSERT_METHOD=LAST;
 show create table t3;
 Table	Create Table
 t3	CREATE TABLE `t3` (
@@ -299,18 +299,18 @@ show create table t5;
 Table	Create Table
 t5	CREATE TABLE `t5` (
   `a` int(11) NOT NULL default '0',
-  `b` int(11) NOT NULL default '0',
-  KEY `a` (`a`,`b`)
+  `b` int(11) NOT NULL auto_increment,
+  PRIMARY KEY  (`a`,`b`)
 ) TYPE=MRG_MyISAM INSERT_METHOD=FIRST UNION=(t1,t2)
 show create table t6;
 Table	Create Table
 t6	CREATE TABLE `t6` (
   `a` int(11) NOT NULL default '0',
-  `b` int(11) NOT NULL default '0',
-  KEY `a` (`a`,`b`)
+  `b` int(11) NOT NULL auto_increment,
+  PRIMARY KEY  (`a`,`b`)
 ) TYPE=MRG_MyISAM INSERT_METHOD=LAST UNION=(t1,t2)
-insert into t1 values (1,1),(1,2),(1,3),(1,4);
-insert into t2 values (2,1),(2,2),(2,3),(2,4);
+insert into t1 values (1,NULL),(1,NULL),(1,NULL),(1,NULL);
+insert into t2 values (2,NULL),(2,NULL),(2,NULL),(2,NULL);
 select * from t3 order by b,a limit 3;
 a	b
 select * from t4 order by b,a limit 3;
@@ -461,6 +461,73 @@ a	b
 5	2
 6	1
 6	2
+select 1;
+1
+1
+insert into t5 values (1,NULL),(5,NULL);
+insert into t6 values (2,NULL),(6,NULL);
+select * from t1 order by a,b;
+a	b
+1	1
+1	2
+1	3
+1	4
+1	5
+4	1
+4	2
+5	1
+5	2
+5	3
+select * from t2 order by a,b;
+a	b
+2	1
+2	2
+2	3
+2	4
+2	5
+6	1
+6	2
+6	3
+select * from t5 order by a,b;
+a	b
+1	1
+1	2
+1	3
+1	4
+1	5
+2	1
+2	2
+2	3
+2	4
+2	5
+4	1
+4	2
+5	1
+5	2
+5	3
+6	1
+6	2
+6	3
+select * from t6 order by a,b;
+a	b
+1	1
+1	2
+1	3
+1	4
+1	5
+2	1
+2	2
+2	3
+2	4
+2	5
+4	1
+4	2
+5	1
+5	2
+5	3
+6	1
+6	2
+6	3
 drop table if exists t6, t5, t4, t3, t2, t1;
 CREATE TABLE t1 (  a int(11) NOT NULL default '0',  b int(11) NOT NULL default '0',  PRIMARY KEY  (a,b)) TYPE=MyISAM;
 INSERT INTO t1 VALUES (1,1), (2,1);

sql/ha_myisammrg.cc

@@ -75,8 +75,7 @@ int ha_myisammrg::write_row(byte * buf)
   if (table->time_stamp)
     update_timestamp(buf+table->time_stamp-1);
   if (table->next_number_field && buf == table->record[0])
-      return (my_errno=HA_ERR_WRONG_COMMAND);
-  //  update_auto_increment(); - [phi] have to check this before allowing it
+      update_auto_increment();
   return myrg_write(file,buf);
 }
 

sql/ha_myisammrg.h

@@ -34,7 +34,7 @@ class ha_myisammrg: public handler
   const char **bas_ext() const;
   ulong table_flags() const
   {
-    return (HA_REC_NOT_IN_SEQ | HA_READ_RND_SAME |
+    return (HA_REC_NOT_IN_SEQ | HA_READ_RND_SAME | HA_AUTO_PART_KEY |
 	    HA_KEYPOS_TO_RNDPOS | HA_LASTKEY_ORDER |
 	    HA_NULL_KEY | HA_BLOB_KEY);
   }

sql/handler.cc

@@ -628,16 +628,29 @@ longlong handler::get_auto_increment()
 {
   longlong nr;
   int error;
+
   (void) extra(HA_EXTRA_KEYREAD);
   index_init(table->next_number_index);
-  error=index_last(table->record[1]);
+  if (!table->next_number_key_offset)
+  {						// Autoincrement at key-start
+    error=index_last(table->record[1]);
+  }
+  else
+  {
+    byte key[MAX_KEY_LENGTH];
+    key_copy(key,table,table->next_number_index,
+             table->next_number_key_offset);
+    error=index_read(table->record[1], key, table->next_number_key_offset,
+                     HA_READ_PREFIX_LAST);
+  }
+
   if (error)
     nr=1;
   else
     nr=(longlong) table->next_number_field->
       val_int_offset(table->rec_buff_length)+1;
-  (void) extra(HA_EXTRA_NO_KEYREAD);
   index_end();
+  (void) extra(HA_EXTRA_NO_KEYREAD);
   return nr;
 }