If @@sql_select_limit is set, followed by a select count
, then the following queries may report wrong results. count(<colname>) has the same behavior.
This behavior is intermittent, meaning it may or may not happen on any given attempt.
2147483647 is max int32_t.
MariaDB [tpch1]> set @@sql_select_limit=4; |
Query OK, 0 rows affected (0.001 sec) |
|
|
MariaDB [tpch1]> create table if not exists bug5054(id int)engine=columnstore; |
Query OK, 0 rows affected (0.519 sec) |
|
|
MariaDB [tpch1]> insert into bug5054 values (1),(2),(3),(4),(5),(6),(7),(8); |
Query OK, 8 rows affected (0.591 sec) |
Records: 8 Duplicates: 0 Warnings: 0 |
|
|
MariaDB [tpch1]> select * from bug5054;
|
+------+
|
| id |
|
+------+
|
| 1 | |
| 2 | |
| 3 | |
| 4 | |
+------+
|
4 rows in set (0.112 sec) // Only 4 are shown because of sql_select_limit |
|
|
MariaDB [tpch1]> select count(*) from bug5054;
|
+----------+
|
| count(*) |
|
+----------+
|
| 8 | |
+----------+
|
1 row in set (2.384 sec) |
|
|
MariaDB [tpch1]> select * from bug5054 limit 10; |
+------+
|
| id |
|
+------+
|
| 1 | |
| 2 | |
| 3 | |
| 4 | |
| 5 | |
| 6 | |
| 7 | |
| 8 | |
+------+
|
8 rows in set (1.774 sec) // Didn't break this time |
|
|
MariaDB [tpch1]> select count(*) from bug5054;
|
+----------+
|
| count(*) |
|
+----------+
|
| 8 | |
+----------+
|
1 row in set (1.877 sec) |
|
|
MariaDB [tpch1]> select * from bug5054 limit 10; |
+------------+
|
| id |
|
+------------+
|
| 2147483647 | |
| 2147483647 | |
| 2147483647 | |
| 2147483647 | |
| 2147483647 | |
| 2147483647 | |
| 2147483647 | |
| 2147483647 | |
+------------+
|
8 rows in set (2.808 sec) |
|
########################################
At this point, in another console:
systemctl stop mariadb
|
systemctl start mariadb
|
|
Do not restart mariadb-columnstore.
Restarting the mysqld process clears up the problem with the table.
MariaDB [tpch1]> select * from bug5054 limit 10; |
ERROR 2006 (HY000): MySQL server has gone away |
No connection. Trying to reconnect...
|
Connection id: 3 |
Current database: tpch1
|
|
|
+------+
|
| id |
|
+------+
|
| 1 | |
| 2 | |
| 3 | |
| 4 | |
| 5 | |
| 6 | |
| 7 | |
| 8 | |
+------+
|
8 rows in set (0.233 sec) |
|