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| author | Evgeny Potemkin <epotemkin@mysql.com> | 2010-02-12 11:51:52 +0300 |
|---|---|---|
| committer | Evgeny Potemkin <epotemkin@mysql.com> | 2010-02-12 11:51:52 +0300 |
| commit | 3e0f70d2cc0d233f0be615532ed3a5254930ad17 (patch) | |
| tree | 7e0ebfd00145b87e6233078f7d11b1e3517fa668 /mysql-test/t/group_min_max.test | |
| parent | 97afccae53a5fda90311f57d328924d736279414 (diff) | |
| download | mariadb-git-3e0f70d2cc0d233f0be615532ed3a5254930ad17.tar.gz | |
Bug#50539: Wrong result when loose index scan is used for an aggregate
function with distinct.
Loose index scan is used to find MIN/MAX values using appropriate index and
thus allow to avoid grouping. For each found row it updates non-aggregated
fields with values from row with found MIN/MAX value.
Without loose index scan non-aggregated fields are copied by end_send_group
function. With loose index scan there is no need in end_send_group and
end_send is used instead. Non-aggregated fields still need to be copied and
this was wrongly implemented in QUICK_GROUP_MIN_MAX_SELECT::get_next.
WL#3220 added a case when loose index scan can be used with end_send_group to
optimize calculation of aggregate functions with distinct. In this case
the row found by QUICK_GROUP_MIN_MAX_SELECT::get_next might belong to a next
group and copying it will produce wrong result.
Update of non-aggregated fields is moved to the end_send function from
QUICK_GROUP_MIN_MAX_SELECT::get_next.
mysql-test/r/group_min_max.result:
Added a test case for the bug#50539.
mysql-test/t/group_min_max.test:
Added a test case for the bug#50539.
sql/opt_range.cc:
Bug#50539: Wrong result when loose index scan is used for an aggregate
function with distinct.
Update of non-aggregated fields is moved to the end_send function from
QUICK_GROUP_MIN_MAX_SELECT::get_next.
sql/sql_select.cc:
Bug#50539: Wrong result when loose index scan is used for an aggregate
function with distinct.
Update of non-aggregated fields is moved to the end_send function from
QUICK_GROUP_MIN_MAX_SELECT::get_next.
Diffstat (limited to 'mysql-test/t/group_min_max.test')
| -rw-r--r-- | mysql-test/t/group_min_max.test | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/mysql-test/t/group_min_max.test b/mysql-test/t/group_min_max.test index 0e6fef9b855..1e7f28d5916 100644 --- a/mysql-test/t/group_min_max.test +++ b/mysql-test/t/group_min_max.test @@ -1166,3 +1166,22 @@ SELECT (SUM(DISTINCT a) + MAX(b)) FROM t2 GROUP BY a; DROP TABLE t1,t2; --echo # end of WL#3220 tests + +--echo # +--echo # Bug#50539: Wrong result when loose index scan is used for an aggregate +--echo # function with distinct +--echo # +CREATE TABLE t1 ( + f1 int(11) NOT NULL DEFAULT '0', + f2 char(1) NOT NULL DEFAULT '', + PRIMARY KEY (f1,f2) +) ; +insert into t1 values(1,'A'),(1 , 'B'), (1, 'C'), (2, 'A'), +(3, 'A'), (3, 'B'), (3, 'C'), (3, 'D'); + +SELECT f1, COUNT(DISTINCT f2) FROM t1 GROUP BY f1; +explain SELECT f1, COUNT(DISTINCT f2) FROM t1 GROUP BY f1; + +drop table t1; +--echo # End of test#50539. + |