Re: [Exist-development] [Exist-open] Performance of concurrent read queries.

[Peter C. <pet...@me...>]

On 1 September 2010 18:09, Jason Smith <js...@in...> wrote:

> Other databases do have high concurrency.  I don't know about XML databases
> though.  I've worked with one in particular that is commercial.  It has a
> collection-based locking model, and it throws deadlock errors occasionally.
>  When this happens, you rollback and start over.
>
> I think I just had an allergic reaction to a pronoun :-).

Let's just take the pronoun out of that paragraph and be clear about what
we're talking about here.  In particular, what is "you"?

In order to be able to start over, "you" must be able to roll back to a
point that is well-defined.  This generally requires transaction boundaries
to be controllable from "you"; if not, "you" cannot determine the point from
which to start over.  In general, the only sensible "you" for this purpose
is the calling application.

Does eXist have transaction boundaries that are controllable from the
calling application?  If not, what other values of "you" might make sense
for this approach?

- Peter