Considerable performance regression on certain queries in maria-5.1-wl24
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
MariaDB |
In Progress
|
High
|
Igor Babaev |
Bug Description
The following query:
SELECT `col_varchar_
WHERE ( `col_varchar_
AND ( `col_varchar_
AND ( ( `col_varchar_
ORDER BY `col_varchar_
Takes no time on maria-5.1 but takes over 1 second on maria-5.1-wl24 . Even if the filesort is avoided by removing the ORDER BY, considerable performance difference remains.
EXPLAIN under maria-5.1:
id: 1
select_type: SIMPLE
table: table100000_
type: range
possible_keys: col_varchar_
key: col_varchar_64_key
key_len: 67
ref: NULL
rows: 99905
Extra: Using where
EXPLAIN under maria-5.1-wl24
id: 1
select_type: SIMPLE
table: table100000_
type: index_merge
possible_keys: col_varchar_
key: col_varchar_
key_len: 13,67
ref: NULL
rows: 54298
Extra: Using sort_union(
The table contains 100K rows and will be uploaded shortly.
Changed in maria: | |
status: | New → Confirmed |
status: | Confirmed → In Progress |
Still repeatable with ------- ------- ------- ------- ------- ------- ------- ----
-------
revno: 2935
committer: Igor Babaev <email address hidden>
branch nick: maria-5.1-wl24
timestamp: Wed 2010-09-15 16:42:56 -0700
message:
Fixed bug #637978.
Fixed a bug in the new code for WL#24 that caused generation of
an invalid index-merge access plan.