Re: Lock-free databases

Mark D Powell wrote:
> If there is any mechanism in the db that single thread access to data
> such as not allowing two processes to change a data item at the same
> time then the db is not "lock" free. The vendor can call the mechanism
> latches or enqueues or anything else but the reality is that the
> mechanism is a lock.
>
> In fact Oracle uses all three terms. A lock, latch, and an enqueue all
> serve the same purpose: single thread access to something. With Oracle
> the difference is what that something is, and how the mechanism is
> implemented. Unless the db is read only I do not see how a db can be
> "lock free". I do not think the claim is honest.
>

I'm referring to the locking used internally in the implementation. If you have locking as part of the external api then you have to provide the correct semantics for it.

-- 
Joe Seigh

When you get lemons, you make lemonade.
When you get hardware, you make software.