database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-30 16:24:05 +03:00
Code Activity

MDEV-27230: Estimation for filtered rows less precise ...

Browse Source 
Fix the code in Histogram_json_hb::range_selectivity that handles
special cases: a non-inclusive endpoint hitting a bucket boundary...
This commit is contained in:
Sergei Petrunia
2021-12-13 23:46:04 +03:00
parent 08f1c4a2e0
commit 905634dc3f
3 changed files with 28 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
mysql-test/main/statistics_json.result
View File

@ -8194,3 +8194,20 @@ 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
drop table t0,t1,t2;
#
# MDEV-27230: Estimation for filtered rows less precise ...
#
create table t1 (a char(1));
insert into t1 select chr(seq%26+97) from seq_1_to_50;
insert into t1 select ':' from t1;
analyze table t1 persistent for all;
Table Op Msg_type Msg_text
test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
analyze select COUNT(*) FROM t1 WHERE a <> 'a';
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 99.00 99.00 Using where
analyze select COUNT(*) FROM t1 WHERE a < 'a';
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 50.00 50.00 Using where
drop table t1;