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MDEV-27229: Estimation for filtered rows less precise ... #5

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Followup: remove this line from get_column_range_cardinality()

      set_if_bigger(res, col_stats->get_avg_frequency());

and make sure it is only used with the binary histograms.
For JSON histograms, it makes the estimates unnecessarily imprecise.
This commit is contained in:
Sergei Petrunia
2022-01-11 16:58:51 +03:00
parent d3e511d421
commit db8f15be93
7 changed files with 33 additions and 16 deletions
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17
mysql-test/main/statistics_json.result
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@ -4644,7 +4644,7 @@ Warnings:
Note 1003 select `test`.`t1_json`.`a` AS `a` from `test`.`t1_json` where `test`.`t1_json`.`a` < 'b-1a'
analyze select * from t1_json where a > 'zzzzzzzzz';
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
1 SIMPLE t1_json ALL NULL NULL NULL NULL 10 10.00 10.00 0.00 Using where
1 SIMPLE t1_json ALL NULL NULL NULL NULL 10 10.00 0.00 0.00 Using where
drop table ten;
UPDATE mysql.column_stats
SET histogram='["not-what-you-expect"]' WHERE table_name='t1_json';
@ -4752,7 +4752,7 @@ id select_type table type possible_keys key key_len ref rows r_rows filtered r_f
1 SIMPLE t2 ALL NULL NULL NULL NULL 101 101.00 1.98 1.98 Using where
explain extended select * from t2 where city < 'Lagos';
id select_type table type possible_keys key key_len ref rows filtered Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 101 50.00 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 101 1.98 Using where
Warnings:
Note 1003 select `test`.`t2`.`city` AS `city` from `test`.`t2` where `test`.`t2`.`city` < 'Lagos'
drop table t1_bin;
@ -8164,7 +8164,7 @@ id select_type table type possible_keys key key_len ref rows r_rows filtered r_f
1 SIMPLE t1 ALL NULL NULL NULL NULL 100 100.00 33.00 33.00 Using where
analyze select * from t1 where a < 0;
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 100 100.00 1.47 0.00 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 100 100.00 1.00 0.00 Using where
analyze select * from t1 where a > 0;
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 100 100.00 67.00 67.00 Using where
@ -8189,7 +8189,7 @@ test.t2 analyze status Engine-independent statistics collected
test.t2 analyze status OK
analyze select * from t2 where a < 1;
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 1011 1011.00 8.33 0.10 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 1011 1011.00 0.10 0.10 Using where
analyze select * from t2 where a =100;
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 1011 1011.00 0.10 0.10 Using where
@ -8237,6 +8237,15 @@ id select_type table type possible_keys key key_len ref rows r_rows filtered r_f
analyze select COUNT(*) FROM t1 WHERE a >='bar';
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 200 200.00 100.00 100.00 Using where
analyze select COUNT(*) FROM t1 WHERE a < 'aaa';
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 200 200.00 0.50 0.00 Using where
analyze select COUNT(*) FROM t1 WHERE a <='aaa';
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 200 200.00 0.50 0.00 Using where
analyze select COUNT(*) FROM t1 WHERE a < 'bar';
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 200 200.00 0.50 0.00 Using where
analyze select COUNT(*) FROM t1 WHERE a <='bar';
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 200 200.00 50.00 50.00 Using where