At 1:35 PM -0500 7/28/99, Thimble Smith wrote:
>At 10:12, 19990728, Scott Hess wrote:
>>Just now, I noticed that if you try to aquire a lock that you already have,
>>mysql first releases the lock before aquiring it.
>>
>>Just wanted to double-check that this is how things are _intended_ to work,
>>rather than just a happy coincidence. The documentation does not say.
>
>The docs do say.
>
>|`GET_LOCK(str,timeout)'
>| ...
>| A lock is released when you execute `RELEASE_LOCK()',
>| execute a new `GET_LOCK()' or the thread terminates.
>| ...
>|
>| mysql> select GET_LOCK("lock1",10);
>| -> 1
>| mysql> select GET_LOCK("lock2",10);
>| -> 1
>| mysql> select RELEASE_LOCK("lock2");
>| -> 1
>| mysql> select RELEASE_LOCK("lock1");
>| -> NULL
>|
>| Note that the second `RELEASE_LOCK()' call returns `NULL' because
>| the lock `"lock1"' was automatically released by the second
>| `GET_LOCK()' call.
>
>Tim
No, that's different. The example gets a lock that you *don't* already
have. It's not clear whether this also applies to the situation
where you try to get a lock that you do already have, though empirically
that seems to be the case.
--
Paul DuBois, paul@stripped
