diff --git a/mysql-test/r/null_key.result b/mysql-test/r/null_key.result index 6eb3cf312a0..0b4ed15f659 100644 --- a/mysql-test/r/null_key.result +++ b/mysql-test/r/null_key.result @@ -30,7 +30,7 @@ id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ref a,b a 5 const 3 Using where; Using index explain select * from t1 where a is null and b=9 or a is null and b=7 limit 3; id select_type table type possible_keys key key_len ref rows Extra -1 SIMPLE t1 ref a,b a 5 const 2 Using where; Using index +1 SIMPLE t1 range a,b a 9 NULL 3 Using where; Using index explain select * from t1 where a > 1 and a < 3 limit 1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 range a a 5 NULL 1 Using where; Using index @@ -258,7 +258,7 @@ INSERT INTO t1 VALUES (1,NULL),(2,NULL),(3,1),(4,2),(5,NULL),(6,NULL),(7,3),(8,4 INSERT INTO t2 VALUES (1,NULL),(2,NULL),(3,1),(4,2),(5,NULL),(6,NULL),(7,3),(8,4),(9,NULL),(10,NULL); explain select id from t1 where uniq_id is null; id select_type table type possible_keys key key_len ref rows Extra -1 SIMPLE t1 ref idx1 idx1 5 const 1 Using where +1 SIMPLE t1 ref idx1 idx1 5 const 5 Using where explain select id from t1 where uniq_id =1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 const idx1 idx1 5 const 1 diff --git a/mysql-test/r/select.result b/mysql-test/r/select.result index 5dcf830ca97..f3938fd6413 100644 --- a/mysql-test/r/select.result +++ b/mysql-test/r/select.result @@ -3642,3 +3642,89 @@ INSERT into t1 values (1), (2), (3); SELECT * FROM t1 LIMIT 2, -1; ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '-1' at line 1 DROP TABLE t1; +CREATE TABLE t1 ( +ID_with_null int NULL, +ID_better int NOT NULL, +INDEX idx1 (ID_with_null), +INDEX idx2 (ID_better) +); +INSERT INTO t1 VALUES (1,1), (2,1), (null,3), (null,3), (null,3), (null,3); +INSERT INTO t1 SELECT * FROM t1 WHERE ID_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID_with_null IS NULL; +SELECT COUNT(*) FROM t1 WHERE ID_with_null IS NULL; +COUNT(*) +128 +SELECT COUNT(*) FROM t1 WHERE ID_better=1; +COUNT(*) +2 +EXPLAIN SELECT * FROM t1 WHERE ID_better=1 AND ID_with_null IS NULL; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 ref idx1,idx2 idx2 4 const 1 Using where +DROP INDEX idx1 ON t1; +CREATE UNIQUE INDEX idx1 ON t1(ID_with_null); +EXPLAIN SELECT * FROM t1 WHERE ID_better=1 AND ID_with_null IS NULL; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 ref idx1,idx2 idx2 4 const 1 Using where +DROP TABLE t1; +CREATE TABLE t1 ( +ID1_with_null int NULL, +ID2_with_null int NULL, +ID_better int NOT NULL, +INDEX idx1 (ID1_with_null, ID2_with_null), +INDEX idx2 (ID_better) +); +INSERT INTO t1 VALUES (1,1,1), (2,2,1), (3,null,3), (null,3,3), (null,null,3), +(3,null,3), (null,3,3), (null,null,3), (3,null,3), (null,3,3), (null,null,3); +INSERT INTO t1 SELECT * FROM t1 WHERE ID1_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID2_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID1_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID2_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID1_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID2_with_null IS NULL; +SELECT COUNT(*) FROM t1 WHERE ID1_with_null IS NULL AND ID2_with_null=3; +COUNT(*) +24 +SELECT COUNT(*) FROM t1 WHERE ID1_with_null=3 AND ID2_with_null IS NULL; +COUNT(*) +24 +SELECT COUNT(*) FROM t1 WHERE ID1_with_null IS NULL AND ID2_with_null IS NULL; +COUNT(*) +192 +SELECT COUNT(*) FROM t1 WHERE ID_better=1; +COUNT(*) +2 +EXPLAIN SELECT * FROM t1 +WHERE ID_better=1 AND ID1_with_null IS NULL AND ID2_with_null=3 ; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 ref idx1,idx2 idx2 4 const 1 Using where +EXPLAIN SELECT * FROM t1 +WHERE ID_better=1 AND ID1_with_null=3 AND ID2_with_null=3 IS NULL ; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 ref idx1,idx2 idx2 4 const 1 Using where +EXPLAIN SELECT * FROM t1 +WHERE ID_better=1 AND ID1_with_null IS NULL AND ID2_with_null IS NULL; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 ref idx1,idx2 idx2 4 const 1 Using where +DROP INDEX idx1 ON t1; +CREATE UNIQUE INDEX idx1 ON t1(ID1_with_null,ID2_with_null); +EXPLAIN SELECT * FROM t1 +WHERE ID_better=1 AND ID1_with_null IS NULL AND ID2_with_null=3 ; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 ref idx1,idx2 idx2 4 const 1 Using where +EXPLAIN SELECT * FROM t1 +WHERE ID_better=1 AND ID1_with_null=3 AND ID2_with_null IS NULL ; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 ref idx1,idx2 idx2 4 const 1 Using where +EXPLAIN SELECT * FROM t1 +WHERE ID_better=1 AND ID1_with_null IS NULL AND ID2_with_null IS NULL; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 ref idx1,idx2 idx2 4 const 1 Using where +EXPLAIN SELECT * FROM t1 +WHERE ID_better=1 AND ID1_with_null IS NULL AND +(ID2_with_null=1 OR ID2_with_null=2); +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 ref idx1,idx2 idx2 4 const 1 Using where +DROP TABLE t1; diff --git a/mysql-test/t/select.test b/mysql-test/t/select.test index 19b625451d4..19c7d742f5b 100644 --- a/mysql-test/t/select.test +++ b/mysql-test/t/select.test @@ -3133,3 +3133,77 @@ SELECT * FROM t1 LIMIT 2, -1; DROP TABLE t1; +# +# 25407: wrong estimate of NULL keys for unique indexes +# + +CREATE TABLE t1 ( + ID_with_null int NULL, + ID_better int NOT NULL, + INDEX idx1 (ID_with_null), + INDEX idx2 (ID_better) +); + +INSERT INTO t1 VALUES (1,1), (2,1), (null,3), (null,3), (null,3), (null,3); +INSERT INTO t1 SELECT * FROM t1 WHERE ID_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID_with_null IS NULL; + +SELECT COUNT(*) FROM t1 WHERE ID_with_null IS NULL; +SELECT COUNT(*) FROM t1 WHERE ID_better=1; + +EXPLAIN SELECT * FROM t1 WHERE ID_better=1 AND ID_with_null IS NULL; + +DROP INDEX idx1 ON t1; +CREATE UNIQUE INDEX idx1 ON t1(ID_with_null); + +EXPLAIN SELECT * FROM t1 WHERE ID_better=1 AND ID_with_null IS NULL; + +DROP TABLE t1; + +CREATE TABLE t1 ( + ID1_with_null int NULL, + ID2_with_null int NULL, + ID_better int NOT NULL, + INDEX idx1 (ID1_with_null, ID2_with_null), + INDEX idx2 (ID_better) +); + +INSERT INTO t1 VALUES (1,1,1), (2,2,1), (3,null,3), (null,3,3), (null,null,3), + (3,null,3), (null,3,3), (null,null,3), (3,null,3), (null,3,3), (null,null,3); + +INSERT INTO t1 SELECT * FROM t1 WHERE ID1_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID2_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID1_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID2_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID1_with_null IS NULL; +INSERT INTO t1 SELECT * FROM t1 WHERE ID2_with_null IS NULL; + +SELECT COUNT(*) FROM t1 WHERE ID1_with_null IS NULL AND ID2_with_null=3; +SELECT COUNT(*) FROM t1 WHERE ID1_with_null=3 AND ID2_with_null IS NULL; +SELECT COUNT(*) FROM t1 WHERE ID1_with_null IS NULL AND ID2_with_null IS NULL; +SELECT COUNT(*) FROM t1 WHERE ID_better=1; + +EXPLAIN SELECT * FROM t1 + WHERE ID_better=1 AND ID1_with_null IS NULL AND ID2_with_null=3 ; +EXPLAIN SELECT * FROM t1 + WHERE ID_better=1 AND ID1_with_null=3 AND ID2_with_null=3 IS NULL ; +EXPLAIN SELECT * FROM t1 + WHERE ID_better=1 AND ID1_with_null IS NULL AND ID2_with_null IS NULL; + +DROP INDEX idx1 ON t1; +CREATE UNIQUE INDEX idx1 ON t1(ID1_with_null,ID2_with_null); + +EXPLAIN SELECT * FROM t1 + WHERE ID_better=1 AND ID1_with_null IS NULL AND ID2_with_null=3 ; +EXPLAIN SELECT * FROM t1 + WHERE ID_better=1 AND ID1_with_null=3 AND ID2_with_null IS NULL ; +EXPLAIN SELECT * FROM t1 + WHERE ID_better=1 AND ID1_with_null IS NULL AND ID2_with_null IS NULL; +EXPLAIN SELECT * FROM t1 + WHERE ID_better=1 AND ID1_with_null IS NULL AND + (ID2_with_null=1 OR ID2_with_null=2); + +DROP TABLE t1; diff --git a/sql/opt_range.cc b/sql/opt_range.cc index 04bc24b718a..f0af4b7db2a 100644 --- a/sql/opt_range.cc +++ b/sql/opt_range.cc @@ -193,6 +193,8 @@ public: } inline void merge_flags(SEL_ARG *arg) { maybe_flag|=arg->maybe_flag; } inline void maybe_smaller() { maybe_flag=1; } + /* Return true iff it's a single-point null interval */ + inline bool is_null_interval() { return maybe_null && max_value[0] == 1; } inline int cmp_min_to_min(SEL_ARG* arg) { return sel_cmp(field,min_value, arg->min_value, min_flag, arg->min_flag); @@ -452,6 +454,7 @@ typedef struct st_qsel_param { bool is_ror_scan; /* Number of ranges in the last checked tree->key */ uint n_ranges; + uint8 first_null_comp; /* first null component if any, 0 - otherwise */ } PARAM; class TABLE_READ_PLAN; @@ -5619,6 +5622,7 @@ check_quick_select(PARAM *param,uint idx,SEL_ARG *tree) DBUG_ENTER("check_quick_select"); param->is_ror_scan= FALSE; + param->first_null_comp= 0; if (!tree) DBUG_RETURN(HA_POS_ERROR); // Can't use it @@ -5710,6 +5714,7 @@ check_quick_keys(PARAM *param,uint idx,SEL_ARG *key_tree, ha_rows records=0, tmp; uint tmp_min_flag, tmp_max_flag, keynr, min_key_length, max_key_length; char *tmp_min_key, *tmp_max_key; + uint8 save_first_null_comp= param->first_null_comp; param->max_key_part=max(param->max_key_part,key_tree->part); if (key_tree->left != &null_element) @@ -5747,6 +5752,9 @@ check_quick_keys(PARAM *param,uint idx,SEL_ARG *key_tree, param->is_ror_scan= FALSE; } + if (!param->first_null_comp && key_tree->is_null_interval()) + param->first_null_comp= key_tree->part+1; + if (key_tree->next_key_part && key_tree->next_key_part->part == key_tree->part+1 && key_tree->next_key_part->type == SEL_ARG::KEY_RANGE) @@ -5790,7 +5798,8 @@ check_quick_keys(PARAM *param,uint idx,SEL_ARG *key_tree, (param->table->key_info[keynr].flags & (HA_NOSAME | HA_END_SPACE_KEY)) == HA_NOSAME && min_key_length == max_key_length && - !memcmp(param->min_key,param->max_key,min_key_length)) + !memcmp(param->min_key,param->max_key,min_key_length) && + !param->first_null_comp) { tmp=1; // Max one record param->n_ranges++; @@ -5865,6 +5874,7 @@ check_quick_keys(PARAM *param,uint idx,SEL_ARG *key_tree, return tmp; records+=tmp; } + param->first_null_comp= save_first_null_comp; return records; }