maria-discuss team mailing list archive

[Elena Stepanova <elenst@xxxxxxxxxxxxxxxx>]

Hi Federico,

On 23.09.2014 12:50, Federico Razzoli wrote:
> Let's make the snippet simpler. Only one table, non-transactional, please look at the difference from what docs say and the real behaviour. If one could explain what UNLOCK TABLES exactly does, it would be great.
>
> MariaDB [test]> SELECT @@in_transaction, @@autocommit;
> +------------------+--------------+
> | @@in_transaction | @@autocommit |
> +------------------+--------------+
> |                0 |            1 |
> +------------------+--------------+
> 1 row in set (0.00 sec)
>
> MariaDB [test]> CREATE OR REPLACE TABLE t (c INT) ENGINE = MEMORY;
> Query OK, 0 rows affected (0.12 sec)
>
> MariaDB [test]> LOCK TABLE t WRITE;
> Query OK, 0 rows affected (0.00 sec)
>
> MariaDB [test]> START TRANSACTION;
> Query OK, 0 rows affected (0.00 sec)

"Beginning a transaction causes table locks acquired with LOCK TABLES to 
be released, as though you had executed UNLOCK TABLES."

http://dev.mysql.com/doc/refman/5.5/en/commit.html

> MariaDB [test]> INSERT INTO t VALUES (1);
> Query OK, 1 row affected (0.01 sec)
>
> MariaDB [test]> UNLOCK TABLES;
> Query OK, 0 rows affected (0.00 sec)

So, this UNLOCK is not actually doing anything.

Regards,
Elena

> MariaDB [test]> SELECT @@in_transaction;
> +------------------+
> | @@in_transaction |
> +------------------+
> |                1 |
> +------------------+
> 1 row in set (0.00 sec)
>
>
> Regards
> Federico
>
>
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