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-18073: get_range_limit_read_cost() doesnt adjust LIMIT for the range access

Browse Source 
The computation about which "fraction" of range/ref access cost we will
need to perform, was incorrect.

Adjusted the computation.
This commit is contained in:
Sergei Petrunia
2019-01-23 16:26:09 +03:00
parent b7a784ae25
commit 3238f2a6e9
3 changed files with 73 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
mysql-test/main/range_vs_index_merge.result
View File

@ -1320,7 +1320,7 @@ WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
AND (Population >= 100000 AND Population < 120000)
ORDER BY Population LIMIT 5;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE City index_merge Country,Name,Population Name,Country 35,3 NULL # Using sort_union(Name,Country); Using where; Using filesort
1 SIMPLE City range Country,Name,Population Population 4 NULL # Using where
FLUSH STATUS;
SELECT * FROM City
WHERE ((Name > 'Ca' AND Name < 'Cf') OR (Country > 'E' AND Country < 'H'))
@ -1335,12 +1335,12 @@ ID Name Country Population
SHOW STATUS LIKE 'Handler_read_%';
Variable_name Value
Handler_read_first 0
Handler_read_key 2
Handler_read_key 1
Handler_read_last 0
Handler_read_next 385
Handler_read_next 59
Handler_read_prev 0
Handler_read_retry 0
Handler_read_rnd 377
Handler_read_rnd 0
Handler_read_rnd_deleted 0
Handler_read_rnd_next 0
set @tmp_mdev585=@@optimizer_use_condition_selectivity;