~drizzle-trunk/drizzle/development

1945.3.5 by Marisa Plumb
more sql doc modifications
1
User Defined Locks
1933.1.9 by Brian Aker
Additional documentation and testing.
2
===================
3
4
A user can create a "lock" which is scoped to their user space. Multiple
5
session of the user can see the lock.
6
7
SELECT GET_LOCK();
8
9
SELECT GET_LOCKS();
10
11
SELECT RELEASE_LOCK();
12
13
SELECT RELEASE_LOCK();
14
15
SELECT RELEASE_LOCKS();
16
17
SELECT is_free_lock();
18
19
SELECT is_used_lock();
20
1955.1.1 by Brian Aker
Finally added pieces so that you can do a drop lock and wait.
21
SELECT wait_for_lock();
22
23
SELECT release_lock_and_wait();
24
1945.3.5 by Marisa Plumb
more sql doc modifications
25
If a session should exit, whatever locks it was holding will be deleted.
1933.1.9 by Brian Aker
Additional documentation and testing.
26
1945.3.5 by Marisa Plumb
more sql doc modifications
27
Please note, get_lock() was designed to be compatible with MySQL. If you
1933.1.9 by Brian Aker
Additional documentation and testing.
28
hold any locks when calling get_lock() they will be released. For this
29
reason you may want to consider calling get_locks() instead.
30
1955.1.1 by Brian Aker
Finally added pieces so that you can do a drop lock and wait.
31
release_lock_and_wait() released the named lock, and then waits for another
32
session to try to obtain ownership. If it does not own the lock, it returns
33
with a zero.
34
1933.1.9 by Brian Aker
Additional documentation and testing.
35
Information on all barriers can be found in the DATA_DICTIONARY.USER_LOCKS
36
table;