From 74d18e93c6a620460fb2f75af11056739fea8f6b Mon Sep 17 00:00:00 2001 From: Igor Babaev Date: Sun, 7 Nov 2010 15:19:30 -0800 Subject: [PATCH] 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. --- mysql-test/r/join_cache.result | 60 ++++++++++++++++++++++++++++++++++ mysql-test/t/join_cache.test | 43 ++++++++++++++++++++++++ sql/sql_select.h | 18 ++++++++++ 3 files changed, 121 insertions(+) diff --git a/mysql-test/r/join_cache.result b/mysql-test/r/join_cache.result index d04a1aaf6a2..f5349320cdc 100644 --- a/mysql-test/r/join_cache.result +++ b/mysql-test/r/join_cache.result @@ -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; diff --git a/mysql-test/t/join_cache.test b/mysql-test/t/join_cache.test index 16bd2d515ad..615c8068c0f 100644 --- a/mysql-test/t/join_cache.test +++ b/mysql-test/t/join_cache.test @@ -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; diff --git a/sql/sql_select.h b/sql/sql_select.h index 363aac90e95..522f1543ad6 100644 --- a/sql/sql_select.h +++ b/sql/sql_select.h @@ -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(©_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