Commit afac3c31 authored by unknown's avatar unknown
Browse files

select.result, select.test: 

  Added a test case for bug #5333.
null_key.result, key_primary.result:
  Made covering index usable for const tables.
sql_select.cc:
  Made covering index usable for const tables:
  downported the corresponding code from 4.1.
  Simultaneously fixed bug #5333 reported for 4.1.
  The bug was due to the fact that field index in join
  structures was always set to 0 for const tables.


sql/sql_select.cc:
  Made covering index usable for const tables:
  downported the corresponding code from 4.1.
  Simultaneously fixed bug #5333 reported for 4.1.
  The bug was due to the fact that field index in join
  structures was always set to 0 for const tables.
mysql-test/t/select.test:
  Added a test case for bug #5333.
mysql-test/r/key_primary.result:
  Made covering index usable for const tables.
mysql-test/r/null_key.result:
  Made covering index usable for const tables.
mysql-test/r/select.result:
  Added a test case for bug #5333.
parent c1fd20bb

mysql-test/r/key_primary.result

+1 −1
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ t1 
AB%

describe select * from t1 where t1="ABC";

table	type	possible_keys	key	key_len	ref	rows	Extra

t1	const	PRIMARY	PRIMARY	3	const	1	

t1	const	PRIMARY	PRIMARY	3	const	1	Using index

describe select * from t1 where t1="ABCD";

Comment

Impossible WHERE noticed after reading const tables

mysql-test/r/null_key.result

+1 −1
Original line number Diff line number Diff line
@@ -12,7 +12,7 @@ table type possible_keys key key_len ref rows Extra 
t1	ref	a,b	a	9	const,const	1	Using where; Using index

explain select * from t1 where a=2 and b = 2;

table	type	possible_keys	key	key_len	ref	rows	Extra

t1	const	a,b	a	9	const,const	1	

t1	const	a,b	a	9	const,const	1	Using index

explain select * from t1 where a<=>b limit 2;

table	type	possible_keys	key	key_len	ref	rows	Extra

t1	index	NULL	a	9	NULL	12	Using where; Using index

mysql-test/r/select.result

+16 −0
Original line number Diff line number Diff line
@@ -2327,3 +2327,19 @@ select * from t2,t3 where t2.s = t3.s; 
s	s

two		two	

drop table t1, t2, t3;

CREATE TABLE t1 (

i int(11) NOT NULL default '0',

c char(10) NOT NULL default '',

PRIMARY KEY  (i),

UNIQUE KEY c (c)

) TYPE=MyISAM;

INSERT INTO t1 VALUES (1,'a');

INSERT INTO t1 VALUES (2,'b');

INSERT INTO t1 VALUES (3,'c');

EXPLAIN SELECT i FROM t1 WHERE i=1;

table	type	possible_keys	key	key_len	ref	rows	Extra

t1	const	PRIMARY	PRIMARY	4	const	1	Using index

EXPLAIN SELECT i FROM t1 WHERE i=1;

table	type	possible_keys	key	key_len	ref	rows	Extra

t1	const	PRIMARY	PRIMARY	4	const	1	Using index

DROP TABLE t1;

mysql-test/t/select.test

+21 −0
Original line number Diff line number Diff line
@@ -1874,3 +1874,24 @@ select * from t3 where s = 'one'; 
select * from t1,t2 where t1.s = t2.s;

select * from t2,t3 where t2.s = t3.s;

drop table t1, t2, t3;



#

# Covering index is mentioned in EXPLAIN output for const tables (bug #5333)

#



CREATE TABLE t1 (

  i int(11) NOT NULL default '0',

  c char(10) NOT NULL default '',

  PRIMARY KEY  (i),

  UNIQUE KEY c (c)

) TYPE=MyISAM;



INSERT INTO t1 VALUES (1,'a');

INSERT INTO t1 VALUES (2,'b');

INSERT INTO t1 VALUES (3,'c');



EXPLAIN SELECT i FROM t1 WHERE i=1;



EXPLAIN SELECT i FROM t1 WHERE i=1;



DROP TABLE t1;
 
 No newline at end of file

sql/sql_select.cc

+10 −1
Original line number Diff line number Diff line
@@ -4901,6 +4901,15 @@ join_read_const_table(JOIN_TAB *tab, POSITION *pos) 
  }

  else

  {

    if (!table->key_read &&

        (table->used_keys & ((key_map) 1 << tab->ref.key)) &&

    	!table->no_keyread &&

        (int) table->reginfo.lock_type <= (int) TL_READ_HIGH_PRIORITY)

    {

      table->key_read=1;

      table->file->extra(HA_EXTRA_KEYREAD);

      tab->index= tab->ref.key;

    }

    if ((error=join_read_const(tab)))

    {

      tab->info="unique row not found";
@@ -7617,7 +7626,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order, 
      sprintf(buff3,"%.0f",join->best_positions[i].records_read);

      item_list.push_back(new Item_string(buff3,strlen(buff3)));

      my_bool key_read=table->key_read;

      if (tab->type == JT_NEXT &&

      if ((tab->type == JT_NEXT || tab->type == JT_CONST) &&

	  ((table->used_keys & ((key_map) 1 << tab->index))))

	key_read=1;