Don't write rows in MyISAM tables when using count(distinct)

Don't read MyISAM header when running without locking

BitKeeper/etc/logging_ok

@@ -11,3 +11,4 @@ sasha@mysql.sashanet.com
 serg@serg.mysql.com
 tim@threads.polyesthetic.msg
 tim@work.mysql.com
+monty@tik.mysql.fi

include/myisam.h

@@ -187,7 +187,7 @@ typedef struct st_columndef		/* column information */
 
 extern my_string myisam_log_filename;		/* Name of logfile */
 extern uint myisam_block_size;
-extern my_bool myisam_flush,myisam_delay_key_write;
+extern my_bool myisam_flush,myisam_delay_key_write,myisam_single_user;
 extern my_bool myisam_concurrent_insert;
 extern my_off_t myisam_max_temp_length,myisam_max_extra_temp_length;
 

myisam/mi_locking.c

@@ -412,11 +412,14 @@ int _mi_mark_file_changed(MI_INFO *info)
       share->global_changed=1;
       share->state.open_count++;
     }
-    mi_int2store(buff,share->state.open_count);
-    buff[2]=1;					/* Mark that it's changed */
-    return (my_pwrite(share->kfile,buff,sizeof(buff),
-		      sizeof(share->state.header),
-		      MYF(MY_NABP)));
+    if (!share->temporary)
+    {
+      mi_int2store(buff,share->state.open_count);
+      buff[2]=1;				/* Mark that it's changed */
+      return (my_pwrite(share->kfile,buff,sizeof(buff),
+			sizeof(share->state.header),
+			MYF(MY_NABP)));
+    }
   }
   return 0;
 }

myisam/mi_open.c

@@ -777,14 +777,17 @@ uint mi_state_info_read_dsk(File file, MI_STATE_INFO *state, my_bool pRead)
 {
   char	buff[MI_STATE_INFO_SIZE + MI_STATE_EXTRA_SIZE];
 
-  if (pRead)
+  if (!myisam_single_user)
   {
-    if (my_pread(file, buff, state->state_length,0L, MYF(MY_NABP)))
+    if (pRead)
+    {
+      if (my_pread(file, buff, state->state_length,0L, MYF(MY_NABP)))
+	return (MY_FILE_ERROR);
+    }
+    else if (my_read(file, buff, state->state_length,MYF(MY_NABP)))
       return (MY_FILE_ERROR);
+    mi_state_info_read(buff, state);
   }
-  else if (my_read(file, buff, state->state_length,MYF(MY_NABP)))
-    return (MY_FILE_ERROR);
-  mi_state_info_read(buff, state);
   return 0;
 }
 

myisam/mi_static.c

@@ -32,7 +32,7 @@ my_string myisam_log_filename=(char*) "myisam.log";
 File	myisam_log_file= -1;
 uint	myisam_quick_table_bits=9;
 uint	myisam_block_size=MI_KEY_BLOCK_LENGTH;		/* Best by test */
-my_bool myisam_flush=0,myisam_delay_key_write=0;
+my_bool myisam_flush=0, myisam_delay_key_write=0, myisam_single_user=0;
 #if defined(THREAD) && !defined(DONT_USE_RW_LOCKS)
 my_bool myisam_concurrent_insert=1;
 #else

mysql-test/r/select_found.result

+a	b
+1	2
+2	3
+3	5
+4	5
+5	5
+6	6
+7	7
+8	9
+FOUND_ROWS()
+8
+a	b
+1	2
+FOUND_ROWS()
+8
+a	b
+8	9
+FOUND_ROWS()
+8
+b
+2
+FOUND_ROWS()
+6
+b	c
+2	1
+FOUND_ROWS()
+6
+a	b	a	b
+3	5	5	5
+FOUND_ROWS()
+8

mysql-test/t/select_found.test

+#
+# Testing of found_rows()
+#
+
+drop table if exists t1;
+create table t1 (a int not null auto_increment, b int not null, primary key(a));
+insert into t1 (b) values (2),(3),(5),(5),(5),(6),(7),(9);
+select SQL_CALC_FOUND_ROWS * from t1;
+select found_rows();
+select SQL_CALC_FOUND_ROWS * from t1 limit 1;
+select found_rows();
+select SQL_CALC_FOUND_ROWS * from t1 order by b desc limit 1;
+select found_rows();
+select SQL_CALC_FOUND_ROWS distinct b from t1 limit 1;
+select found_rows();
+select SQL_CALC_FOUND_ROWS b,count(*) as c from t1 group by b order by c limit 1;
+select found_rows();
+select SQL_CALC_FOUND_ROWS * from t1 left join t1 as t2 on (t1.b=t2.a) limit 2,1;
+select found_rows(); 
+drop table t1;

sql/item_sum.cc

@@ -867,6 +867,7 @@ bool Item_sum_count_distinct::setup(THD *thd)
 			       0, 0, current_lex->options | thd->options)))
     return 1;
   table->file->extra(HA_EXTRA_NO_ROWS);		// Don't update rows
+  table->no_rows=1;
 
   if(table->db_type == DB_TYPE_HEAP) // no blobs, otherwise it would be
     // MyISAM

sql/mysqld.cc

@@ -3028,14 +3028,13 @@ static void usage(void)
   puts("\
   -O, --set-variable var=option\n\
 			Give a variable an value. --help lists variables\n\
-  -Sg, --skip-grant-tables\n\
-			Start without grant tables. This gives all users\n\
-			FULL ACCESS to all tables!\n\
   --safe-mode		Skip some optimize stages (for testing)\n\
   --skip-concurrent-insert\n\
 		        Don't use concurrent insert with MyISAM\n\
   --skip-delay-key-write\n\
 			Ignore the delay_key_write option for all tables\n\
+  --skip-grant-tables	Start without grant tables. This gives all users\n\
+			FULL ACCESS to all tables!\n\
   --skip-host-cache	Don't cache host names\n\
   --skip-locking	Don't use system locking. To use isamchk one has\n\
 			to shut down the server.\n\
@@ -3172,7 +3171,7 @@ static void set_options(void)
 #endif
 
 #if defined( HAVE_mit_thread ) || defined( __WIN__ ) || defined( HAVE_LINUXTHREADS )
-  my_disable_locking = 1;
+  my_disable_locking=myisam_single_user= 1;
 #endif
   my_bind_addr = htonl( INADDR_ANY );
 }
@@ -3265,20 +3264,6 @@ static void get_options(int argc,char **argv)
       test_flags= optarg ? (uint) atoi(optarg) : 0;
       opt_endinfo=1;
       break;
-    case 'S':
-      if (!optarg)
-	opt_specialflag|= SPECIAL_NO_NEW_FUNC | SPECIAL_SAFE_MODE;
-      else if (!strcmp(optarg,"l"))
-	my_disable_locking=1;
-      else if (!strcmp(optarg,"g"))
-	opt_noacl=1;
-      else
-      {
-	fprintf(stderr,"%s: Unrecognized option: %s\n",my_progname,optarg);
-	use_help();
-	exit(1);
-      }
-      break;
     case (int) OPT_BIG_TABLES:
       thd_startup_options|=OPTION_BIG_TABLES;
       break;
@@ -3456,7 +3441,7 @@ static void get_options(int argc,char **argv)
       opt_noacl=1;
       break;
     case (int) OPT_SKIP_LOCK:
-      my_disable_locking=1;
+      my_disable_locking=myisam_single_user= 1;
       break;
     case (int) OPT_SKIP_HOST_CACHE:
       opt_specialflag|= SPECIAL_NO_HOST_CACHE;
@@ -4022,7 +4007,7 @@ static int get_service_parameters()
     }
     else if ( lstrcmp(szKeyValueName, TEXT("KeyBufferSize")) == 0 )
     {
-      SET_CHANGEABLE_VARVAL( "key_buffer" );
+      SET_CHANGEABLE_VARVAL( "key_buffer_size" );
     }
     else if ( lstrcmp(szKeyValueName, TEXT("LongQueryTime")) == 0 )
     {

sql/sql_analyse.h

@@ -21,8 +21,6 @@
 #pragma interface				/* gcc class implementation */
 #endif
 
-#include <my_tree.h>
-
 #define DEC_IN_AVG 4
 
 typedef struct st_number_info

sql/sql_select.cc

@@ -69,7 +69,7 @@ static COND *remove_eq_conds(COND *cond,Item::cond_result *cond_value);
 static bool const_expression_in_where(COND *conds,Item *item, Item **comp_item);
 static bool open_tmp_table(TABLE *table);
 static bool create_myisam_tmp_table(TABLE *table,TMP_TABLE_PARAM *param,
-				    uint options);
+				    ulong options);
 static int do_select(JOIN *join,List<Item> *fields,TABLE *tmp_table,
 		     Procedure *proc);
 static int sub_select_cache(JOIN *join,JOIN_TAB *join_tab,bool end_of_records);
@@ -3317,7 +3317,7 @@ Field *create_tmp_field(TABLE *table,Item *item, Item::Type type,
 TABLE *
 create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
 		 ORDER *group, bool distinct, bool save_sum_fields,
-		 bool allow_distinct_limit, uint select_options)
+		 bool allow_distinct_limit, ulong select_options)
 {
   TABLE *table;
   uint	i,field_count,reclength,null_count,null_pack_length,
@@ -3759,7 +3759,7 @@ static bool open_tmp_table(TABLE *table)
 
 
 static bool create_myisam_tmp_table(TABLE *table,TMP_TABLE_PARAM *param,
-				    uint options)
+				    ulong options)
 {
   int error;
   MI_KEYDEF keydef;
@@ -3926,6 +3926,12 @@ bool create_myisam_from_heap(TABLE *table, TMP_TABLE_PARAM *param, int error,
     goto err1;
   table->file->index_end();
   table->file->rnd_init();
+  if (table->no_rows)
+  {
+    new_table->file->extra(HA_EXTRA_NO_ROWS);
+    new_table->no_rows=1;
+  }
+
   /* copy all old rows */
   while (!table->file->rnd_next(new_table.record[1]))
   {

sql/sql_select.h

@@ -181,7 +181,7 @@ void TEST_join(JOIN *join);
 bool store_val_in_field(Field *field,Item *val);
 TABLE *create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
 			ORDER *group, bool distinct, bool save_sum_fields,
-			bool allow_distinct_limit, uint select_options);
+			bool allow_distinct_limit, ulong select_options);
 void free_tmp_table(THD *thd, TABLE *entry);
 void count_field_types(TMP_TABLE_PARAM *param, List<Item> &fields,
 		       bool reset_with_sum_func);

sql/table.h

@@ -89,7 +89,7 @@ struct st_table {
   my_bool copy_blobs;			/* copy_blobs when storing */
   my_bool null_row;			/* All columns are null */
   my_bool maybe_null,outer_join;	/* Used with OUTER JOIN */
-  my_bool distinct,const_table;
+  my_bool distinct,const_table,no_rows;
   my_bool key_read;
   my_bool crypted;
   my_bool db_low_byte_first;		/* Portable row format */