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Fixed bug #36632: SELECT DISTINCT from a simple view on an

Browse Source 
InnoDB table, where all selected columns
                  belong to the same unique index key, returns
                  incorrect results

Server executes some queries via QUICK_GROUP_MIN_MAX_SELECT
(MIN/MAX optimization for queries with GROUP BY or DISTINCT
clause) and that optimization implies loose index scan, so all
grouping is done by the QUICK_GROUP_MIN_MAX_SELECT::get_next
method.

The server does not set the precomputed_group_by flag for some
QUICK_GROUP_MIN_MAX_SELECT queries and duplicates grouping by
call to the end_send_group function.

Fix: when the test_if_skip_sort_order function selects loose 
index scan as a best way to satisfy an ORDER BY/GROUP BY type
of query, the precomputed_group_by flag has been set to use 
end_send/end_write functions instead of end_send_group/
end_write_group functions.


mysql-test/r/group_min_max_innodb.result:
  Fixed bug #36632: SELECT DISTINCT from a simple view on an
                    InnoDB table, where all selected columns
                    belong to the same unique index key, returns
                    incorrect results
mysql-test/t/group_min_max_innodb.test:
  Fixed bug #36632: SELECT DISTINCT from a simple view on an
                    InnoDB table, where all selected columns
                    belong to the same unique index key, returns
                    incorrect results
sql/sql_select.cc:
  Fixed bug #36632: SELECT DISTINCT from a simple view on an
                    InnoDB table, where all selected columns
                    belong to the same unique index key, returns
                    incorrect results
This commit is contained in:
Gleb Shchepa 2008-06-27 23:50:53 +05:00
parent fb8f32d077
commit a8067140e8
3 changed files with 50 additions and 0 deletions
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24
mysql-test/r/group_min_max_innodb.result
View File

@ -1,3 +1,5 @@
drop view if exists v1;
drop table if exists t1,t4;
create table t4 (
pk_col int auto_increment primary key, a1 char(64), a2 char(64), b char(16), c char(16) not null, d char(16), dummy char(64) default ' '
) engine=innodb;
@ -70,3 +72,25 @@ explain select distinct f1, f2 from t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL PRIMARY 5 NULL 3 Using index for group-by; Using temporary
drop table t1;
create table t1(pk int primary key) engine=innodb;
create view v1 as select pk from t1 where pk < 20;
insert into t1 values (1), (2), (3), (4);
select distinct pk from v1;
pk
1
2
3
4
insert into t1 values (5), (6), (7);
select distinct pk from v1;
pk
1
2
3
4
5
6
7
drop view v1;
drop table t1;
End of 5.1 tests

24
mysql-test/t/group_min_max_innodb.test
View File

@ -6,6 +6,11 @@
--source include/have_innodb.inc
--disable_warnings
drop view if exists v1;
drop table if exists t1,t4;
--enable_warnings
#
# Bug #12672: primary key implcitly included in every innodb index
#
@ -93,3 +98,22 @@ alter table t1 drop primary key, add primary key (f2, f1);
explain select distinct f1 a, f1 b from t1;
explain select distinct f1, f2 from t1;
drop table t1;
#
# Bug #36632: Select distinct from a simple view on an InnoDB table
# returns incorrect results
#
create table t1(pk int primary key) engine=innodb;
create view v1 as select pk from t1 where pk < 20;
insert into t1 values (1), (2), (3), (4);
select distinct pk from v1;
insert into t1 values (5), (6), (7);
select distinct pk from v1;
drop view v1;
drop table t1;
--echo End of 5.1 tests

2
sql/sql_select.cc
View File

@ -13177,6 +13177,8 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
tab->ref.key= -1;
tab->ref.key_parts=0; // Don't use ref key.
tab->read_first_record= join_init_read_record;
if (tab->is_using_loose_index_scan())
join->tmp_table_param.precomputed_group_by= TRUE;
/*
TODO: update the number of records in join->best_positions[tablenr]
*/