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Fixed LP bug #671901. 

Currently BNLH join uses a simplified implementation of hash function
when hash function is calculated over the whole key buffer, not only
the significant bytes of it. It means that both building keys and
probing keys both must fill insignificant bytes with the same filler.
Usually 0 is used as such a filler.
Yet the code before patch filled insignificant bytes only for probing
keys.
pull/374/head
Igor Babaev 15 years ago
parent
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74d18e93c6
3 changed files with 121 additions and 0 deletions
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  1. 60
      mysql-test/r/join_cache.result
  2. 43
      mysql-test/t/join_cache.test
  3. 18
      sql/sql_select.h

60
mysql-test/r/join_cache.result
View File

@ -5615,4 +5615,64 @@ a c
SET SESSION join_cache_level = DEFAULT;
SET SESSION join_buffer_size = DEFAULT;
DROP TABLE t1,t2;
#
# Bug #671901: hash join using a ref to a varchar field
#
CREATE TABLE t1 (
v varchar(10) CHARACTER SET latin1 COLLATE latin1_bin DEFAULT NULL,
i int DEFAULT NULL
);
INSERT INTO t1 VALUES
('k',8), ('abcdefjh',-575340544), ('f',77), ('because', 2), ('f',-517472256),
('abcdefjhj',5), ('z',7);
CREATE TABLE t2 (
v varchar(10) CHARACTER SET latin1 COLLATE latin1_bin DEFAULT NULL,
i int DEFAULT NULL,
INDEX idx (v)
);
INSERT INTO t2 VALUES
('did',5), ('was',-1631322112), ('are',3), ('abcdefjhjk',3),
('abcdefjhjk',4), ('tell',-824573952), ('t',0),('v',-1711013888),
('abcdefjhjk',1015414784), ('or',4), ('now',0), ('abcdefjhjk',-32702464),
('abcdefjhjk',4), ('time',1078394880), ('f',4), ('m',-1845559296),
('ff', 5), ('abcdefjhjk',-1074397184);
EXPLAIN
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = t1.v;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 7 Using where
1 SIMPLE t2 ref idx idx 13 test.t1.v 2
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = t1.v;
v i
f 4
f 4
EXPLAIN
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = concat(t1.v, t1.v);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 7
1 SIMPLE t2 ref idx idx 13 func 2 Using index condition
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = concat(t1.v, t1.v);
v i
f 5
f 5
SET SESSION join_cache_level = 4;
EXPLAIN
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = t1.v;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 7 Using where
1 SIMPLE t2 ref idx idx 13 test.t1.v 2 Using join buffer (flat, BNLH join)
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = t1.v;
v i
f 4
f 4
EXPLAIN
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = concat(t1.v, t1.v);
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 7
1 SIMPLE t2 ref idx idx 13 func 2 Using where; Using join buffer (flat, BNLH join)
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = concat(t1.v, t1.v);
v i
f 5
f 5
SET SESSION join_cache_level = DEFAULT;
DROP TABLE t1,t2;
set @@optimizer_switch=@save_optimizer_switch;

43
mysql-test/t/join_cache.test
View File

@ -2315,5 +2315,48 @@ SET SESSION join_buffer_size = DEFAULT;
DROP TABLE t1,t2;
--echo #
--echo # Bug #671901: hash join using a ref to a varchar field
--echo #
CREATE TABLE t1 (
v varchar(10) CHARACTER SET latin1 COLLATE latin1_bin DEFAULT NULL,
i int DEFAULT NULL
);
INSERT INTO t1 VALUES
('k',8), ('abcdefjh',-575340544), ('f',77), ('because', 2), ('f',-517472256),
('abcdefjhj',5), ('z',7);
CREATE TABLE t2 (
v varchar(10) CHARACTER SET latin1 COLLATE latin1_bin DEFAULT NULL,
i int DEFAULT NULL,
INDEX idx (v)
);
INSERT INTO t2 VALUES
('did',5), ('was',-1631322112), ('are',3), ('abcdefjhjk',3),
('abcdefjhjk',4), ('tell',-824573952), ('t',0),('v',-1711013888),
('abcdefjhjk',1015414784), ('or',4), ('now',0), ('abcdefjhjk',-32702464),
('abcdefjhjk',4), ('time',1078394880), ('f',4), ('m',-1845559296),
('ff', 5), ('abcdefjhjk',-1074397184);
EXPLAIN
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = t1.v;
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = t1.v;
EXPLAIN
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = concat(t1.v, t1.v);
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = concat(t1.v, t1.v);
SET SESSION join_cache_level = 4;
EXPLAIN
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = t1.v;
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = t1.v;
EXPLAIN
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = concat(t1.v, t1.v);
SELECT t1.v,t2.i FROM t1,t2 WHERE t2.v = concat(t1.v, t1.v);
SET SESSION join_cache_level = DEFAULT;
DROP TABLE t1,t2;
# this must be the last command in the file
set @@optimizer_switch=@save_optimizer_switch;

18
sql/sql_select.h
View File

@ -2431,6 +2431,15 @@ class store_key_field: public store_key
TABLE *table= copy_field.to_field->table;
my_bitmap_map *old_map= dbug_tmp_use_all_columns(table,
table->write_set);
/*
It looks like the next statement is needed only for a simplified
hash function over key values used now in BNLH join.
When the implementation of this function will be replaced for a proper
full version this statement probably should be removed.
*/
bzero(copy_field.to_ptr,copy_field.to_length);
copy_field.do_copy(&copy_field);
dbug_tmp_restore_column_map(table->write_set, old_map);
null_key= to_field->is_null();
@ -2464,6 +2473,15 @@ public:
my_bitmap_map *old_map= dbug_tmp_use_all_columns(table,
table->write_set);
int res= FALSE;
/*
It looks like the next statement is needed only for a simplified
hash function over key values used now in BNLH join.
When the implementation of this function will be replaced for a proper
full version this statement probably should be removed.
*/
to_field->reset();
if (use_value)
item->save_val(to_field);
else

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