maria-developers team mailing list archive

[Sergey Petrunia <sergey@xxxxxxxxxxx>]

Hi Sergei,

* what about persistent virtual columns? Do we still support
environment-dependent virtual functions for those?

* the behavior of current solution is not deterministic:

thread1> select @@time_zone;
+-------------+
| @@time_zone |
+-------------+
| SYSTEM      |
+-------------+
1 row in set (0.00 sec)

thread1> create table t2 ( a varchar(32), b int, v varchar(100) as (from_unixtime(b)));
Query OK, 0 rows affected (0.28 sec)

thread1> insert into t2 (a,b) values ('local-tz-23-11', unix_timestamp());
Query OK, 1 row affected (0.04 sec)

thread1> select * from t2;
+----------------+------------+---------------------+
| a              | b          | v                   |
+----------------+------------+---------------------+
| local-tz-23-11 | 1416427891 | 2014-11-19 23:11:31 |
+----------------+------------+---------------------+
1 row in set (0.00 sec)

thread2> set time_zone='Europe/Helsinki';
Query OK, 0 rows affected (0.00 sec)

thread2> select * from t2;
+----------------+------------+---------------------+
| a              | b          | v                   |
+----------------+------------+---------------------+
| local-tz-23-11 | 1416427891 | 2014-11-19 23:11:31 |
+----------------+------------+---------------------+
1 row in set (0.00 sec)

thread2> flush tables;
Query OK, 0 rows affected (0.00 sec)

thread2> select * from t2;
+----------------+------------+---------------------+
| a              | b          | v                   |
+----------------+------------+---------------------+
| local-tz-23-11 | 1416427891 | 2014-11-19 22:11:31 |
+----------------+------------+---------------------+
1 row in set (0.00 sec)


Is this really ok? Maybe, it makes sense to use some some "default"
(e.g. global variables) environment on the non-deterministic 
virtual column functions?

Or, make these functions always fetch the environment from the 
current thread?


On Mon, Nov 17, 2014 at 09:43:46AM +0100, Sergei Golubchik wrote:
> At lp:~maria-captains/maria/5.5
> 
> ------------------------------------------------------------
> revno: 4358
> revision-id: sergii@xxxxxxxxx-20141115155753-rx5twf6utu1isczh
> parent: sergii@xxxxxxxxx-20141113173729-hirl67og6at3xbni
> fixes bugs: https://mariadb.atlassian.net/browse/MDEV-6789 https://mariadb.atlassian.net/browse/MDEV-7113
> committer: Sergei Golubchik <sergii@xxxxxxxxx>
> branch nick: 5.5
> timestamp: Sat 2014-11-15 16:57:53 +0100
> message:
>   MDEV-7113 difference between check_vcol_func_processor and check_partition_func_processor
>   MDEV-6789 segfault in Item_func_from_unixtime::get_date on updating table with virtual columns
>   
>   * prohibit VALUES in partitioning expression
>   * prohibit user and system variables in virtual column expressions
>   * fix Item_func_date_format to cache locale (for %M/%W to return the same as MONTHNAME/DAYNAME)
>   * fix Item_func_from_unixtime to cache time_zone directly, not THD (and not to crash)
>   * added tests for other incorrectly allowed (in vcols) functions to see that they don't crash
...

BR
 Sergei
-- 
Sergei Petrunia, Software Developer
MariaDB Corporation | Skype: sergefp | Blog: http://s.petrunia.net/blog