Re: What is the implications of Level# for a latch?

"Niraj Mehta" <mehta_niraj_at_hotmail.com> wrote in message news:<9md1qb$des$1_at_newsreader.mailgate.org>...
> Hello,
>
> I have been searching extensively in the Oracle documentation, what exactly
> does the Level# for a latch (in V$LATCH view) imply.

Latches have a Level# that is used to prevent deadlocks. Once a process acquires a latch at a certain level#, it cannot then subsequently acquire another latch at the same or a lesser level (unless it acquires it nowait).

Try out this scenario and you will see that you cannot create a deadlock, if you keep the above rule in mind: Latch Level#

A       1
B       3
C       3
D       4
E       6
F       6

... If you use this logic in designing locking for the tables. You can virtually eliminate table deadlocks. That is, if you set a rule for your developers to only lock tables in a certain order, there is no way they can code a deadlock.

:0)
Anurag Received on Mon Aug 27 2001 - 09:41:54 CDT