Re: using DBI for mutual exclusion across multiple servers

On Mar 11, 2010, at 2:15 PM, Jared Still wrote:

> On Thu, Mar 11, 2010 at 1:57 PM, Jonathan Swartz <[email protected]>  
> wrote:
> Ok. Sounds like this is more expensive than I expected (at least in  
> Oracle's case).
>
> Does it save any cost that the update is a "dummy" update, "update  
> id = 1 where id = 1"? That is, I'm only using the update to reserve  
> the row, not actually changing any data.
>
>
> That is database and database version dependent.
>
> The best way to discover the answer to this would be to
> run a trace of the operations. In the case of Oracle that
> would be a 10046 trace. I don't know about others.
>
> Is this being done on an Oracle database?

No, Sybase. Sadly (because very few people use it, hence difficult to  
get information about it).