Increase max package length to 512M for mysql and mysqldump.

Faster 'read_first_row' (Fixes slow 'preparing' state)
Read constant tables earlier, which provides better optimzations when using tables with <=1 row.
This also fixes a complicated bug involving const tables.

Docs/manual.texi

@@ -810,14 +810,14 @@ is pushed up to 8 million terabytes (2 ^ 63 bytes).
 Note, however, that operating systems have their own file size
 limits. Here are some examples:
 
-@multitable @columnfractions .5 .5
+@multitable @columnfractions .6 .4
 @item @strong{Operating System} @tab @strong{File Size Limit}
 @item Linux-Intel 32 bit        @tab 2G, 4G or more, depends on Linux version
 @item Linux-Alpha               @tab 8T (?)
 @item Solaris 2.5.1             @tab 2G (possible 4G with patch)
 @item Solaris 2.6               @tab 4G
 @item Solaris 2.7 Intel         @tab 4G
-@item Solaris 2.7 ULTRA-SPARC   @tab 8T (?)
+@item Solaris 2.7 ULTRA-SPARC @tab 512G
 @end multitable
 
 On Linux 2.2 you can get bigger tables than 2G by using the LFS patch for
@@ -5480,7 +5480,6 @@ pipes.
 All of the above binaries are optimised for the Pentium Pro
 processor but should work on any Intel processor >= i386.
 
-
 In the following circumstances you will need to use the MySQL
 configuration file:
 @itemize @bullet
@@ -5498,17 +5497,23 @@ If you want to use one of the these servers:
 If you need to tune the server settings.
 @end itemize
 
-There are two configuration files with the same function:
-@file{my.cnf} and @file{my.ini} file, however please note that
-only of one these should can used. Both files are plain text.
-The @file{my.cnf} file should be created in the root directory
-of drive C and the @file{my.ini} file on the WinDir directory
-e.g: @file{C:\WINDOWS} or @file{C:\WINNT}.
-If your PC uses a boot loader where the C drive isn't the boot
-drive, then your only option is to use the @file{my.ini} file.
-Also note that if you use the @code{WinMySQLAdmin} tool, only
-the @file{my.ini} file is used. The @file{\mysql\bin} directory
-contains a help file with instructions for using this tool.
+Normally you can use the @code{WinMySQLAdmin} tool to edit the
+configuration file @code{my.ini}. In this case you don't have to worry
+about the following section.
+
+There are two configuration files with the same function: @file{my.cnf}
+and @file{my.ini} file, however please note that only of one these
+should be used to avoid confusion. Both files are plain text.  The
+@file{my.cnf} file , if used, should be created in the root directory of
+drive C and the @file{my.ini} file on the WinDir directory e.g:
+@file{C:\WINDOWS} or @file{C:\WINNT}.  MySQL will first read the
+@code{my.ini} file, followed by the @code{my.cnf} file.
+
+If your PC uses a boot loader where the C drive isn't the boot drive,
+then your only option is to use the @file{my.ini} file.  Also note that
+if you use the @code{WinMySQLAdmin} tool, only the @file{my.ini} file is
+used by this tool. The @file{\mysql\bin} directory contains a help file
+with instructions for using this tool.
 
 Using @code{notepad.exe}, create the configuration file and
 edit the base section and keys:
@@ -5781,11 +5786,12 @@ release or the last stable release:
 
 @itemize @bullet
 @item
-Normally, if you are beginning to use MySQL for the first time
-or trying to port it to some system for which there is no binary
-distribution, we recommend going with the stable release (currently
-Version 3.23.  Note that all MySQL releases are checked with the
-MySQL benchmarks and an extensive test suite before each release.
+Normally, if you are beginning to use MySQL for the first time or trying
+to port it to some system for which there is no binary distribution, we
+recommend going with the stable release (currently Version 3.23.  Note
+that all MySQL releases are checked with the MySQL benchmarks and an
+extensive test suite before each release (even the development
+releases).
 
 @item
 Otherwise, if you are running an old system and want to upgrade, but
@@ -6046,7 +6052,8 @@ Stable tested releases are meant to appear about 1-2 times a year, but
 if small bugs are found, a release with only bug fixes will be released.
 
 @item
-Working releases are meant to appear about every 1-8 weeks.
+Working releases/bug fixes to old releases are meant to appear about
+every 1-8 weeks.
 
 @item
 Binary distributions for some platforms will be made by us for major releases.
@@ -6055,12 +6062,12 @@ less frequently.
 
 @item
 We usually make patches available as soon as we have located and fixed
-small bugs.
+small bugs. They are posted to @email{bugs@@lists.mysql.com} and will
+be added to the next release.
 
 @item
-For non-critical but annoying bugs, we will make patches available if they
-are sent to us.  Otherwise we will combine many of them into a larger
-patch.
+For non-critical but annoying bugs, we will add them the MySQL source
+repository and they will be fixed in the next release.
 
 @item
 If there is, by any chance, a fatal bug in a release we will make a new
@@ -6075,6 +6082,10 @@ and things that ``must be done.''  ``Somewhat frozen'' means that we may
 add small things that ``almost surely will not affect anything that's
 already working.''
 
+MySQL uses a little different naming scheme that most other products.
+In general it's relatively safe to use any version that has been out for
+a couple of weeks without being replaced with a new version.
+@xref{Which version}.
 
 @node MySQL binaries, Installing binary, Many versions, General Installation Issues
 @subsection MySQL Binaries Compiled by MySQL AB
@@ -19487,7 +19498,7 @@ bytes when needed.  This value by default is small, to catch big (possibly
 wrong) packets.  You must increase this value if you are using big
 @code{BLOB} columns. It should be as big as the biggest @code{BLOB} you want
 to use.  The protocol limits for @code{max_allowed_packet} is 16M in MySQL
-3.23 and 4G in MySQL 4.0.
+3.23 and 2G in MySQL 4.0.
   
 @item @code{max_binlog_cache_size}
 If a multi-statement transaction requires more than this amount of memory,
@@ -36746,6 +36757,11 @@ The following are the known problems with @code{MERGE} tables:
 
 @itemize @bullet
 @item
+@code{MERGE} table cannot maintain UNIQUE constraints over the whole
+table.  When you do INSERT, the data goes into the first or last table
+(according to @code{INSERT_METHOD=xxx}) and this MyISAM table ensures
+that the data are unique, but it knows nothing about the first MyISAM table.
+@item
 @code{DELETE FROM merge_table} used without a @code{WHERE}
 will only clear the mapping for the table, not delete everything in the
 mapped tables.
@@ -38643,6 +38659,7 @@ Finland
 * BDB characteristics::         Characteristics of @code{BDB} tables:
 * BDB TODO::                    Things we need to fix for BDB in the near future:
 * BDB portability::             Operating systems supported by @strong{BDB}
+* BDB restrictions::            
 * BDB errors::                  Errors That May Occur When Using BDB Tables
 @end menu
 
@@ -38851,7 +38868,7 @@ Change to not use page locks at all when we are scanning tables.
 @end itemize
 
 
-@node BDB portability, BDB errors, BDB TODO, BDB
+@node BDB portability, BDB restrictions, BDB TODO, BDB
 @subsection Operating systems supported by @strong{BDB}
 
 If you after having built MySQL with support for BDB tables get
@@ -38891,8 +38908,28 @@ Linux 2.x Alpha
 Max OS X
 @end itemize
 
+@node BDB restrictions, BDB errors, BDB portability, BDB
+@subsection Restrictions on BDB Tables
+
+Here follows the restrictions you have when using BDB tables:
 
-@node BDB errors,  , BDB portability, BDB
+@itemize @bullet
+@item
+BDB tables store in the .db file the path to the file as it was created
+(My guess is that this is to be able to detect locks in a multi-user
+environment that supports symlinks).
+
+The effect of this is that BDB tables are not movable between directories!  
+@item
+When taking backups of BDB tables, you have to either use
+@code{mysqldump} or take a backup of all @code{table_name.db} files and
+the BDB log files.  The BDB log files are the files in the base data
+directory named @code{log.XXXXXX} (6 digits);
+The BDB table handler stores unfinished transactions in the log files
+and requires these to be present when @code{mysqld} starts.
+@end itemize
+
+@node BDB errors,  , BDB restrictions, BDB
 @subsection Errors That May Occur When Using BDB Tables
 
 @itemize @bullet
@@ -45281,6 +45318,11 @@ When a MySQL client or the @code{mysqld} server gets a packet bigger
 than @code{max_allowed_packet} bytes, it issues a @code{Packet too large}
 error and closes the connection.
 
+In MySQL 3.23 the biggest possible packet is 16M (due to limits in the
+client/server protocol). In MySQL 4.0.1 and up, this is only limited by
+the amount on memory you have on your server (up to a theoretical
+maximum of 2G).
+
 A communication packet is a single SQL statement sent to the MySQL server
 or a single row that is sent to the client.
 
@@ -47090,11 +47132,6 @@ New version of netadmin. See above for details.
 Atronic's MySQL client for Windows 2.0.3.0.
 The home page for this can be found at @uref{http://www.artronic.hr/}.
 
-@item @uref{http://www.mysql.com/Downloads/Win32/mysqlfront.zip}
-MySQL Front, home page: @uref{http://www.mysqlfront.de/}.
-Win32-Client for accessing and managing dbs, tables, table-data, indexes,
-import-/export-files. (Freeware).  By Ansgar Becker.
-
 @item @uref{http://www.mysql.com/Downloads/Win32/W9xstop.zip}
 Utility from Artronic to stop MySQL on win9x.
 
@@ -48135,6 +48172,14 @@ Our TODO section contains what we plan to have in 4.0. @xref{TODO MySQL 4.0}.
 
 @itemize @bullet
 @item
+Fixed optimization problem where a MySQL was a long time in a
+"preparing" state when selecting from an empty table which had contained
+a lot of rows.
+@item
+Fixed bug in complicated join with @code{const} tables. This fix also
+improves performance a bit when referring to another table from a
+@code{const} table.
+@item
 Fixed bug in multi table delete.
 @item
 Fixed bug in @code{SELECT CONCAT(argument-list) ... GROUP BY 1}.

client/mysql.cc

@@ -477,8 +477,8 @@ static struct option long_options[] =
 CHANGEABLE_VAR changeable_vars[] = {
   { "connect_timeout", (long*) &opt_connect_timeout, 0, 0, 3600*12, 0, 1},
   { "max_allowed_packet", (long*) &max_allowed_packet,16*1024L*1024L,4096,
-    24*1024L*1024L, MALLOC_OVERHEAD,1024},
-  { "net_buffer_length",(long*) &net_buffer_length,16384,1024,24*1024*1024L,
+    512*1024L*1024L, MALLOC_OVERHEAD,1024},
+  { "net_buffer_length",(long*) &net_buffer_length,16384,1024,512*1024*1024L,
     MALLOC_OVERHEAD,1024},
   { "select_limit", (long*) &select_limit, 1000L, 1, ~0L, 0, 1},
   { "max_join_size", (long*) &max_join_size, 1000000L, 1, ~0L, 0, 1},

client/mysqldump.c

@@ -147,9 +147,9 @@ static const char *load_default_groups[]= { "mysqldump","client",0 };
 
 CHANGEABLE_VAR md_changeable_vars[] = {
   { "max_allowed_packet", (long*) &max_allowed_packet,24*1024*1024,4096,
-    24*1024L*1024L,MALLOC_OVERHEAD,1024},
+    512*1024L*1024L,MALLOC_OVERHEAD,1024},
   { "net_buffer_length", (long*) &net_buffer_length,1024*1024L-1025,4096,
-    24*1024L*1024L,MALLOC_OVERHEAD,1024},
+    512*1024L*1024L,MALLOC_OVERHEAD,1024},
   { 0, 0, 0, 0, 0, 0, 0}
 };
 

dbug/dbug.c

@@ -1928,7 +1928,7 @@ static void dbug_flush(CODE_STATE *state)
     {
       if (!(freopen(stack->name,"a",_db_fp_)))
       {
-	(void) fprintf(stderr, ERR_OPEN, _db_process_);
+	(void) fprintf(stderr, ERR_OPEN, _db_process_, stack->name);
 	fflush(stderr);
 	_db_fp_ = stdout;
 	stack -> out_file = _db_fp_;

mysql-test/t/innodb.test

@@ -577,3 +577,51 @@ handler t1 read t first;
 --error 1109
 handler t1 close;
 drop table t1;
+
+#
+# Test of multi-table-delete
+#
+
+CREATE TABLE t1 (
+  number bigint(20) NOT NULL default '0',
+  cname char(15) NOT NULL default '',
+  carrier_id smallint(6) NOT NULL default '0',
+  privacy tinyint(4) NOT NULL default '0',
+  last_mod_date timestamp(14) NOT NULL,
+  last_mod_id smallint(6) NOT NULL default '0',
+  last_app_date timestamp(14) NOT NULL,
+  last_app_id smallint(6) default '-1',
+  version smallint(6) NOT NULL default '0',
+  assigned_scps int(11) default '0',
+  status tinyint(4) default '0'
+) TYPE=InnoDB;
+INSERT INTO t1 VALUES (4077711111,'SeanWheeler',90,2,20020111112846,500,00000000000000,-1,2,3,1);
+INSERT INTO t1 VALUES (9197722223,'berry',90,3,20020111112809,500,20020102114532,501,4,10,0);
+INSERT INTO t1 VALUES (650,'San Francisco',0,0,20011227111336,342,00000000000000,-1,1,24,1);
+INSERT INTO t1 VALUES (302467,'Sue\'s Subshop',90,3,20020109113241,500,20020102115111,501,7,24,0);
+INSERT INTO t1 VALUES (6014911113,'SudzCarwash',520,1,20020102115234,500,20020102115259,501,33,32768,0);
+INSERT INTO t1 VALUES (333,'tubs',99,2,20020109113440,501,20020109113440,500,3,10,0);
+CREATE TABLE t2 (
+  number bigint(20) NOT NULL default '0',
+  cname char(15) NOT NULL default '',
+  carrier_id smallint(6) NOT NULL default '0',
+  privacy tinyint(4) NOT NULL default '0',
+  last_mod_date timestamp(14) NOT NULL,
+  last_mod_id smallint(6) NOT NULL default '0',
+  last_app_date timestamp(14) NOT NULL,
+  last_app_id smallint(6) default '-1',
+  version smallint(6) NOT NULL default '0',
+  assigned_scps int(11) default '0',
+  status tinyint(4) default '0'
+) TYPE=InnoDB;
+INSERT INTO t2 VALUES (4077711111,'SeanWheeler',0,2,20020111112853,500,00000000000000,-1,2,3,1);
+INSERT INTO t2 VALUES (9197722223,'berry',90,3,20020111112818,500,20020102114532,501,4,10,0);
+INSERT INTO t2 VALUES (650,'San Francisco',90,0,20020109113158,342,00000000000000,-1,1,24,1);
+INSERT INTO t2 VALUES (333,'tubs',99,2,20020109113453,501,20020109113453,500,3,10,0);
+select * from t1;
+select * from t2;
+delete t1, t2 from t1 left join t2 on t1.number=t2.number where (t1.carrier_id=90 and t1.number=t2.number) or (t2.carrier_id=90 and t1.number=t2.number) or  (t1.carrier_id=90 and t2.number is null);
+select * from t1;
+select * from t2; 
+select * from t2;
+drop table t1,t2;

sql/handler.cc

@@ -472,17 +472,36 @@ int handler::analyze(THD* thd, HA_CHECK_OPT* check_opt)
   return HA_ADMIN_NOT_IMPLEMENTED;
 }
 
-	/* Read first row from a table */
+/*
+  Read first row (only) from a table
+  This is never called for InnoDB or BDB tables, as these table types
+  has the HA_NOT_EXACT_COUNT set.
+*/
 
-int handler::rnd_first(byte * buf)
+int handler::read_first_row(byte * buf, uint primary_key)
 {
   register int error;
-  DBUG_ENTER("handler::rnd_first");
+  DBUG_ENTER("handler::read_first_row");
 
   statistic_increment(ha_read_first_count,&LOCK_status);
+
+  /*
+    If there is very few deleted rows in the table, find the first row by
+    scanning the table.
+  */
+  if (deleted < 10 || primary_key >= MAX_KEY)
+  {
     (void) rnd_init();
     while ((error= rnd_next(buf)) == HA_ERR_RECORD_DELETED) ;
     (void) rnd_end();
+  }
+  else
+  {
+    /* Find the first row through the primary key */
+    (void) index_init(primary_key);
+    error=index_first(buf);
+    (void) index_end();
+  }
   DBUG_RETURN(error);
 }
 
@@ -498,7 +517,7 @@ int handler::restart_rnd_next(byte *buf, byte *pos)
 }
 
 
-	/* Set a timestamp in record */
+/* Set a timestamp in record */
 
 void handler::update_timestamp(byte *record)
 {
@@ -514,9 +533,10 @@ void handler::update_timestamp(byte *record)
   return;
 }
 
-	/* Updates field with field_type NEXT_NUMBER according to following:
-	** if field = 0 change field to the next free key in database.
-	*/
+/*
+  Updates field with field_type NEXT_NUMBER according to following:
+  if field = 0 change field to the next free key in database.
+*/
 
 void handler::update_auto_increment()
 {

sql/handler.h

@@ -269,7 +269,7 @@ public:
   virtual int rnd_end() { return 0; }
   virtual int rnd_next(byte *buf)=0;
   virtual int rnd_pos(byte * buf, byte *pos)=0;
-  virtual int rnd_first(byte *buf);
+  virtual int read_first_row(byte *buf, uint primary_key);
   virtual int restart_rnd_next(byte *buf, byte *pos);
   virtual ha_rows records_in_range(int inx,
 			           const byte *start_key,uint start_key_len,

sql/opt_range.cc

@@ -585,6 +585,9 @@ int SQL_SELECT::test_quick_select(key_map keys_to_use, table_map prev_tables,
   uint idx;
   double scan_time;
   DBUG_ENTER("test_quick_select");
+  DBUG_PRINT("enter",("keys_to_use: %lu  prev_tables: %lu  const_tables: %lu",
+		      (ulong) keys_to_use, (ulong) prev_tables,
+		      (ulong) const_tables));
 
   delete quick;
   quick=0;

sql/sql_select.cc

@@ -41,6 +41,8 @@ static bool update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,
                                 uint tables,COND *conds,table_map table_map);
 static int sort_keyuse(KEYUSE *a,KEYUSE *b);
 static void set_position(JOIN *join,uint index,JOIN_TAB *table,KEYUSE *key);
+static bool create_ref_for_key(JOIN *join, JOIN_TAB *j, KEYUSE *org_keyuse,
+			       table_map used_tables);
 static void find_best_combination(JOIN *join,table_map rest_tables);
 static void find_best(JOIN *join,table_map rest_tables,uint index,
 		      double record_count,double read_time);
@@ -84,7 +86,7 @@ static int end_unique_update(JOIN *join,JOIN_TAB *join_tab,
 static int end_write_group(JOIN *join, JOIN_TAB *join_tab,
 			   bool end_of_records);
 static int test_if_group_changed(List<Item_buff> &list);
-static int join_read_const_tables(JOIN *join);
+static int join_read_const_table(JOIN_TAB *tab, POSITION *pos);
 static int join_read_system(JOIN_TAB *tab);
 static int join_read_const(JOIN_TAB *tab);
 static int join_read_key(JOIN_TAB *tab);
@@ -413,9 +415,8 @@ mysql_select(THD *thd,TABLE_LIST *tables,List<Item> &fields,COND *conds,
     goto err;
   thd->proc_info="preparing";
   result->initialize_tables(&join);
-  if ((tmp=join_read_const_tables(&join)) > 0)
-    goto err;
-  if (tmp && !(select_options & SELECT_DESCRIBE))
+  if (join.const_table_map != join.found_const_table_map &&
+      !(select_options & SELECT_DESCRIBE))
   {
     error=return_zero_rows(result,tables,fields,
 			   join.tmp_table_param.sum_func_count != 0 &&
@@ -903,7 +904,7 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
 {
   int error;
   uint i,table_count,const_count,found_ref,refs,key,const_ref,eq_part;
-  table_map const_table_map,all_table_map;
+  table_map const_table_map,found_const_table_map,all_table_map;
   TABLE **table_vector;
   JOIN_TAB *stat,*stat_end,*s,**stat_ref;
   SQL_SELECT *select;
@@ -923,7 +924,7 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
   join->best_ref=stat_vector;
 
   stat_end=stat+table_count;
-  const_table_map=all_table_map=0;
+  const_table_map=found_const_table_map=all_table_map=0;
   const_count=0;
 
   for (s=stat,i=0 ; tables ; s++,tables=tables->next,i++)
@@ -938,13 +939,13 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
     bzero((char*) table->const_key_parts, sizeof(key_part_map)*table->keys);
     all_table_map|= table->map;
     s->join=join;
+    s->info=0;					// For describe
     if ((s->on_expr=tables->on_expr))
     {
+      /* Left join */
       if (!table->file->records)
       {						// Empty table
-	s->key_dependent=s->dependent=0;
-	s->type=JT_SYSTEM;
-	const_table_map|=table->map;
+	s->key_dependent=s->dependent=0;	// Ignore LEFT JOIN depend.
 	set_position(join,const_count++,s,(KEYUSE*) 0);
 	continue;
       }
@@ -965,8 +966,6 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
     if ((table->system || table->file->records <= 1) && ! s->dependent &&
 	!(table->file->option_flag() & HA_NOT_EXACT_COUNT))
     {
-      s->type=JT_SYSTEM;
-      const_table_map|=table->map;
       set_position(join,const_count++,s,(KEYUSE*) 0);
     }
   }
@@ -974,10 +973,10 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
   join->outer_join=outer_join;
 
   /*
-  ** If outer join: Re-arrange tables in stat_vector so that outer join
-  ** tables are after all tables it is dependent of.
-  ** For example: SELECT * from A LEFT JOIN B ON B.c=C.c, C WHERE A.C=C.C
-  ** Will shift table B after table C.
+    If outer join: Re-arrange tables in stat_vector so that outer join
+    tables are after all tables it is dependent of.
+    For example: SELECT * from A LEFT JOIN B ON B.c=C.c, C WHERE A.C=C.C
+    Will shift table B after table C.
   */
   if (outer_join)
   {
@@ -1014,31 +1013,66 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
                             conds,~outer_join))
       DBUG_RETURN(1);
 
+  /* Read tables with 0 or 1 rows (system tables) */
+  join->const_table_map=const_table_map;
+
+  for (POSITION *p_pos=join->positions, *p_end=p_pos+const_count;
+       p_pos < p_end ;
+       p_pos++)
+  {
+    int tmp;
+    s= p_pos->table;
+    s->type=JT_SYSTEM;
+    join->const_table_map|=s->table->map;
+    if ((tmp=join_read_const_table(s, p_pos)))
+    {
+      if (tmp > 0)
+	DBUG_RETURN(1);			// Fatal error
+    }
+    else
+      found_const_table_map|= s->table->map;
+  }
+
   /* loop until no more const tables are found */
   int ref_changed;
   do
   {
     ref_changed = 0;
     found_ref=0;
-    for (JOIN_TAB **pos=stat_vector+const_count; (s= *pos) ; pos++)
+
+    /*
+      We only have to loop from stat_vector + const_count as
+      set_position() will move all const_tables first in stat_vector
+    */
+
+    for (JOIN_TAB **pos=stat_vector+const_count ; (s= *pos) ; pos++)
     {
+      TABLE *table=s->table;
       if (s->dependent)				// If dependent on some table
       {
-	if (s->dependent & ~(const_table_map)) // All dep. must be constants
+	// All dep. must be constants
+	if (s->dependent & ~(join->const_table_map))
 	  continue;
-	if (s->table->file->records <= 1L &&
-	    !(s->table->file->option_flag() & HA_NOT_EXACT_COUNT))
+	if (table->file->records <= 1L &&
+	    !(table->file->option_flag() & HA_NOT_EXACT_COUNT))
 	{					// system table
+	  int tmp;
 	  s->type=JT_SYSTEM;
-	  const_table_map|=s->table->map;
+	  join->const_table_map|=table->map;
 	  set_position(join,const_count++,s,(KEYUSE*) 0);
+	  if ((tmp=join_read_const_table(s,join->positions+const_count-1)))
+	  {
+	    if (tmp > 0)
+	      DBUG_RETURN(1);			// Fatal error
+	  }
+	  else
+	    found_const_table_map|= table->map;
 	  continue;
 	}
       }
       /* check if table can be read by key or table only uses const refs */
       if ((keyuse=s->keyuse))
       {
-	TABLE *table=s->table;
 	s->type= JT_REF;
 	while (keyuse->table == table)
 	{
@@ -1051,7 +1085,7 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
 	  {
 	    if (keyuse->val->type() != Item::NULL_ITEM)
 	    {
-	      if (!((~const_table_map) & keyuse->used_tables))
+	      if (!((~join->const_table_map) & keyuse->used_tables))
 		const_ref|= (key_map) 1 << keyuse->keypart;
 	      else
 		refs|=keyuse->used_tables;
@@ -1065,10 +1099,22 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
 	  {
 	    if (const_ref == eq_part)
 	    {					// Found everything for ref.
+	      int tmp;
+	      ref_changed = 1;
 	      s->type=JT_CONST;
-	      const_table_map|=table->map;
+	      join->const_table_map|=table->map;
 	      set_position(join,const_count++,s,start_keyuse);
-	      ref_changed = 1;
+	      if (create_ref_for_key(join, s, start_keyuse,
+				     join->const_table_map))
+		DBUG_RETURN(1);
+	      if ((tmp=join_read_const_table(s,
+					     join->positions+const_count-1)))
+	      {
+		if (tmp > 0)
+		  DBUG_RETURN(1);			// Fatal error
+	      }
+	      else
+		found_const_table_map|= table->map;
 	      break;
 	    }
 	    else
@@ -1077,7 +1123,7 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
 	}
       }
     }
-  } while (const_table_map & found_ref && ref_changed);
+  } while (join->const_table_map & found_ref && ref_changed);
 
   /* Calc how many (possible) matched records in each table */
 
@@ -1093,8 +1139,10 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
     s->found_records=s->records=s->table->file->records;
     s->read_time=(ha_rows) s->table->file->scan_time();
 
-    /* Set a max range of how many seeks we can expect when using keys */
-    /* This was (s->read_time*5), but this was too low with small rows */
+    /*
+      Set a max range of how many seeks we can expect when using keys
+      This was (s->read_time*5), but this was too low with small rows
+    */
     s->worst_seeks= (double) s->found_records / 5;
     if (s->worst_seeks < 2.0)			// Fix for small tables
       s->worst_seeks=2.0;
@@ -1105,15 +1153,14 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
     {
       ha_rows records;
       if (!select)
-	select=make_select(s->table,const_table_map,
-			   0,
+	select=make_select(s->table, join->const_table_map,
+			   join->const_table_map,
 			   and_conds(conds,s->on_expr),&error);
       records=get_quick_record_count(select,s->table, s->const_keys,
 				     join->row_limit);
       s->quick=select->quick;
       s->needed_reg=select->needed_reg;
       select->quick=0;
-      select->read_tables=const_table_map;
       if (records != HA_POS_ERROR)
       {
 	s->found_records=records;
@@ -1128,10 +1175,10 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
   join->map2table=stat_ref;
   join->table= join->all_tables=table_vector;
   join->const_tables=const_count;
-  join->const_table_map=const_table_map;
+  join->found_const_table_map=found_const_table_map;
 
   if (join->const_tables != join->tables)
-    find_best_combination(join,all_table_map & ~const_table_map);
+    find_best_combination(join,all_table_map & ~join->const_table_map);
   else
   {
     memcpy((gptr) join->best_positions,(gptr) join->positions,
@@ -2040,12 +2087,10 @@ prev_record_reads(JOIN *join,table_map found_ref)
 static bool
 get_best_combination(JOIN *join)
 {
-  uint i,key,tablenr;
+  uint i,tablenr;
   table_map used_tables;
-  TABLE *table;
   JOIN_TAB *join_tab,*j;
   KEYUSE *keyuse;
-  KEY *keyinfo;
   uint table_count;
   THD *thd=join->thd;
 
@@ -2054,8 +2099,6 @@ get_best_combination(JOIN *join)
 	(JOIN_TAB*) thd->alloc(sizeof(JOIN_TAB)*table_count)))
     return TRUE;
 
-  join->const_tables=0;				/* for checking */
-  join->const_table_map=0;
   join->full_join=0;
 
   used_tables=0;
@@ -2064,41 +2107,52 @@ get_best_combination(JOIN *join)
     TABLE *form;
     *j= *join->best_positions[tablenr].table;
     form=join->table[tablenr]=j->table;
-    j->ref.key = -1;
-    j->ref.key_parts=0;
-    j->info=0;					// For describe
     used_tables|= form->map;
     form->reginfo.join_tab=j;
     if (!j->on_expr)
       form->reginfo.not_exists_optimize=0;	// Only with LEFT JOIN
+    if (j->type == JT_CONST)
+      continue;					// Handled in make_join_stat..
+
+    j->ref.key = -1;
+    j->ref.key_parts=0;
 
     if (j->type == JT_SYSTEM)
-    {
-      j->table->const_table=1;
-      if (join->const_tables == tablenr)
-      {
-	join->const_tables++;
-	join->const_table_map|=form->map;
-      }
       continue;
-    }
     if (!j->keys || !(keyuse= join->best_positions[tablenr].key))
     {
       j->type=JT_ALL;
       if (tablenr != join->const_tables)
 	join->full_join=1;
     }
-    else
-    {
-      uint keyparts,length;
+    else if (create_ref_for_key(join, j, keyuse, used_tables))
+      return TRUE;				// Something went wrong
+  }
+
+  for (i=0 ; i < table_count ; i++)
+    join->map2table[join->join_tab[i].table->tablenr]=join->join_tab+i;
+  update_depend_map(join);
+  return 0;
+}
+
+
+static bool create_ref_for_key(JOIN *join, JOIN_TAB *j, KEYUSE *org_keyuse,
+			       table_map used_tables)
+{
+  KEYUSE *keyuse=org_keyuse;
   bool ftkey=(keyuse->keypart == FT_KEYPART);
+  THD  *thd= join->thd;
+  uint keyparts,length,key;
+  TABLE *table;
+  KEY *keyinfo;
+
   /*
   ** Use best key from find_best
   */
   table=j->table;
   key=keyuse->key;
-
   keyinfo=table->key_info+key;
+
   if (ftkey)
   {
     Item_func_match *ifm=(Item_func_match *)keyuse->val;
@@ -2138,7 +2192,7 @@ get_best_combination(JOIN *join)
   }
   j->ref.key_buff2=j->ref.key_buff+ALIGN_SIZE(length);
   j->ref.key_err=1;
-      keyuse=join->best_positions[tablenr].key;
+  keyuse=org_keyuse;
 
   store_key **ref_key=j->ref.key_copy;
   byte *key_buff=j->ref.key_buff;
@@ -2152,6 +2206,7 @@ get_best_combination(JOIN *join)
   }
   else
   {
+    uint i;
     for (i=0 ; i < keyparts ; keyuse++,i++)
     {
       while (keyuse->keypart != i ||
@@ -2178,7 +2233,7 @@ get_best_combination(JOIN *join)
 	tmp->copy();
       }
       else
-	    *ref_key++= get_store_key(join->thd,
+	*ref_key++= get_store_key(thd,
 				  keyuse,join->const_table_map,
 				  &keyinfo->key_part[i],
 				  (char*) key_buff,maybe_null);
@@ -2188,15 +2243,9 @@ get_best_combination(JOIN *join)
   *ref_key=0;				// end_marker
   if (j->type == JT_FT)  /* no-op */;
   else if (j->type == JT_CONST)
-      {
     j->table->const_table=1;
-	if (join->const_tables == tablenr)
-	{
-	  join->const_tables++;
-	  join->const_table_map|=form->map;
-	}
-      }
-      else if (((keyinfo->flags & (HA_NOSAME | HA_NULL_PART_KEY)) != HA_NOSAME) ||
+  else if (((keyinfo->flags & (HA_NOSAME | HA_NULL_PART_KEY))
+	    != HA_NOSAME) ||
 	   keyparts != keyinfo->key_parts)
     j->type=JT_REF;				/* Must read with repeat */
   else if (ref_key == j->ref.key_copy)
@@ -2209,24 +2258,14 @@ get_best_combination(JOIN *join)
       have a 'normal' value or a NULL value.
     */
     j->type=JT_CONST;
-	if (join->const_tables == tablenr)
-	{
-	  join->const_tables++;
-	  join->const_table_map|=form->map;
-	}
   }
   else
     j->type=JT_EQ_REF;
-    }
-  }
-
-  for (i=0 ; i < table_count ; i++)
-    join->map2table[join->join_tab[i].table->tablenr]=join->join_tab+i;
-  update_depend_map(join);
   return 0;
 }
 
 
+
 static store_key *
 get_store_key(THD *thd, KEYUSE *keyuse, table_map used_tables,
 	      KEY_PART_INFO *key_part, char *key_buff, uint maybe_null)
@@ -3163,13 +3202,13 @@ remove_eq_conds(COND *cond,Item::cond_result *cond_value)
 	   ((Item_func*) cond)->functype() == Item_func::ISNULL_FUNC)
   {
     /*
-    ** Handles this special case for some ODBC applications:
-    ** The are requesting the row that was just updated with a auto_increment
-    ** value with this construct:
-    **
-    ** SELECT * from table_name where auto_increment_column IS NULL
-    ** This will be changed to:
-    ** SELECT * from table_name where auto_increment_column = LAST_INSERT_ID
+      Handles this special case for some ODBC applications:
+      The are requesting the row that was just updated with a auto_increment
+      value with this construct:
+
+      SELECT * from table_name where auto_increment_column IS NULL
+      This will be changed to:
+      SELECT * from table_name where auto_increment_column = LAST_INSERT_ID
     */
 
     Item_func_isnull *func=(Item_func_isnull*) cond;
@@ -4365,45 +4404,44 @@ flush_cached_records(JOIN *join,JOIN_TAB *join_tab,bool skipp_last)
 *****************************************************************************/
 
 static int
-join_read_const_tables(JOIN *join)
+join_read_const_table(JOIN_TAB *tab, POSITION *pos)
 {
-  uint i;
   int error;
-  DBUG_ENTER("join_read_const_tables");
-  for (i=0 ; i < join->const_tables ; i++)
-  {
-    TABLE *form=join->table[i];
-    form->null_row=0;
-    form->status=STATUS_NO_RECORD;
+  DBUG_ENTER("join_read_const_table");
+  TABLE *table=tab->table;
+  table->const_table=1;
+  table->null_row=0;
+  table->status=STATUS_NO_RECORD;
   
-    if (join->join_tab[i].type == JT_SYSTEM)
+  if (tab->type == JT_SYSTEM)
   {
-      if ((error=join_read_system(join->join_tab+i)))
+    if ((error=join_read_system(tab)))
     {						// Info for DESCRIBE
-	join->join_tab[i].info="const row not found";
-	join->best_positions[i].records_read=0.0;
-	if (!form->outer_join || error > 0)
+      tab->info="const row not found";
+      /* Mark for EXPLAIN that the row was not found */
+      pos->records_read=0.0;
+      if (!table->outer_join || error > 0)
 	DBUG_RETURN(error);
     }
   }
   else
   {
-      if ((error=join_read_const(join->join_tab+i)))
+    if ((error=join_read_const(tab)))
     {
-	join->join_tab[i].info="unique row not found";
-	join->best_positions[i].records_read=0.0;
-	if (!form->outer_join || error > 0)
+      tab->info="unique row not found";
+      /* Mark for EXPLAIN that the row was not found */
+      pos->records_read=0.0;
+      if (!table->outer_join || error > 0)
 	DBUG_RETURN(error);
     }
   }
-    if (join->join_tab[i].on_expr && !form->null_row)
+  if (tab->on_expr && !table->null_row)
   {
-      if ((form->null_row= test(join->join_tab[i].on_expr->val_int() == 0)))
-	empty_record(form);
-    }
-    if (!form->null_row)
-      form->maybe_null=0;
+    if ((table->null_row= test(tab->on_expr->val_int() == 0)))
+      empty_record(table);
     }
+  if (!table->null_row)
+    table->maybe_null=0;
   DBUG_RETURN(0);
 }
 
@@ -4415,7 +4453,8 @@ join_read_system(JOIN_TAB *tab)
   int error;
   if (table->status & STATUS_GARBAGE)		// If first read
   {
-    if ((error=table->file->rnd_first(table->record[0])))
+    if ((error=table->file->read_first_row(table->record[0],
+					   table->primary_key)))
     {
       if (error != HA_ERR_END_OF_FILE)
       {

sql/sql_select.h

@@ -158,7 +158,7 @@ class JOIN {
   uint	   send_group_parts;
   bool	   sort_and_group,first_record,full_join,group, no_field_update;
   bool	   do_send_rows;
-  table_map const_table_map,outer_join;
+  table_map const_table_map,found_const_table_map,outer_join;
   ha_rows  send_records,found_records,examined_rows,row_limit;
   POSITION positions[MAX_TABLES+1],best_positions[MAX_TABLES+1];
   double   best_read;