Ayende, Assuming you're referring to me, I am talking about saga persisters,
not finders.  I think a db-based saga persister with explicit row-locking
would cover 90% of needs, but I fully accept that a DHT/PHT implementation
would be better.  I spent the evening exploring the load balancer, so I
didn't quite make it to saga persistence with the DHT.  And heck, you
probably know better anyways!

Udi, the reason I stuck with a simple one-table approach is that I didn't
want to create NH objects and mappings for every saga state class.  I have
about a hundred saga state classes in the project I am involved in at the
moment, and some of those classes have fairly deep relations.  Dumping them
into a single table with Xml Serialization suited my needs perfectly and
saved me a LOT of development time.

-tyler

On Sun, Sep 6, 2009 at 5:40 AM, Ayende Rahien <[email protected]> wrote:

>
> Oh you are talking about saga finders
>
> On Sunday, September 6, 2009, Udi Dahan <[email protected]>
> wrote:
> >
> > The reason we moved to the NHibernateSagaPersister is that we could
> > use it to automatically generate a schema for the user's saga objects
> > including the appropriate indexable columns. This means users don't
> > need to understand more than to point it at a given database and it'll
> > install and go.
> >
> > Hope that makes sense.
> >
> > -- Udi Dahan
> >
> >
> > On Sep 5, 10:05 pm, Tyler Burd <[email protected]> wrote:
> >> I completely agree that an NH dependency would be bad.  I think a
> vanilla
> >> ADO persister would be a good thing to include.
> >>
> >> NSB used to have the DbBlobSagaPersister.  It would be nice if there was
> >> something similar in RSB, but using an NTEXT field and the message
> >> serializer instead of binary serialization.
> >>
> >> On Sat, Sep 5, 2009 at 4:00 AM, Ayende Rahien <[email protected]>
> wrote:
> >> > Jason,Because they brought a lot of complexity to the table.
> >> > I actually think that the local DHT + optimistic is something that I
> would
> >> > like to end up with.
> >> > We can specify a local, self deployed, version for development, and
> scale
> >> > up for a remote one for farm scenario and a full DHT cluster for
> >> > reliability.
> >>
> >> > On Fri, Sep 4, 2009 at 11:54 PM, Jason Meckley <
> [email protected]>wrote:
> >>
> >> >> I dug into the code and this finally clicked and I understand the
> >> >> problem of balancing configuration & extensibility.
> >> >> I spend most of my time in the previous revision since it's all in
> >> >> tack.
> >> >> in looking through it I can understand why you want to re-design how
> >> >> DHT works. Why remove the persister strategies and local DHT Client
> >> >> though? that all seems to work without issue.
> >>
> >> >> I think a db persister would be straight forward. were talking about
> a
> >> >> single table with 6 columns. wrap ADO.Net with a simple facade and
> >> >> call it a day.  you could add a deploy action to build the schema.
> >> >> have it pull from the config file and add the table under another
> >> >> schema. similar to Rhino.Security.
> >>
> >> >> tyler i would be interested in your database implementation. for my
> >> >> immediate need I ported Local DHT Client and OptimisticStatePersister
> >> >> to my project to work against the latest RSB build.
> >>
> >> >> On Sep 3, 9:36 am, Tyler Burd <[email protected]> wrote:
> >> >> > I'm currently using a custom saga persister that I'd be happy to
> share,
> >> >> but
> >> >> > it uses NH and I doubt you want to make that a dependency of RSB.
>  I
> >> >> found
> >> >> > it was simple to write (5 minutes), simple to understand, and it
> just
> >> >> > works.  I didn't need *extreme* throughput, though, and I expect
> that's
> >> >> the
> >> >> > case for the vast majority of projects, so my vote is +1 for a
> simple db
> >> >> > persister.  It's still going to be a hell of a lot more scalable
> than a
> >> >> > traditional thread hungry ASP NET app.
> >>
> >> >> > -tyler
> >>
> >> >> > On Wed, Sep 2, 2009 at 4:43 PM, Ayende Rahien <[email protected]>
> >> >> wrote:
> >> >> > > Right now I am working on the ESB parts of the port, and I am
> thinking
> >> >> hard
> >> >> > > again about what should and shouldn't be in there.On the one
> hand, one
> >> >> of
> >> >> > > the major reasons that I created RSB is that I wanted to make
> >> >> something that
> >> >> > > is developer friendly and easy to get started.
> >> >> > > On the other hand, there are some things where we do want to
> provide
> >> >> > > extensibility and customization for the users.
> >> >> > > For the most part, I think we managed to do that by using the
> >> >> container in
> >> >> > > some clever ways, but with the DHT saga storage I think I really
> >> >> messed it
> >> >> > > up.
> >> >> > > It is complex, both to set it up and to make use of it and to
> >> >> understand
> >> >> > > how it works.
> >> >> > > I have tentatively removed it from the project.
> >> >> > > I would like to provide a saga storage that is easy to use and
> fit the
> >> >> bill
> >> >> > > for most of the operations that you need, without bringing undue
> >> >> burden for
> >> >> > > the administrator or developer.
> >>
> >> >> > > Last week I had several discussions with Udi about that, and he
> >> >> pointed out
> >> >> > > that the most commonly used and easiest to reason about is a
> locked
> >> >> saga
> >> >> > > state. That is, during the execution of a transaction, the state
> of
> >> >> the saga
> >> >> > > is locked. A common example would be using a DB to handle that
> while
> >> >> using
> >> >> > > serializable transactions.
> >>
> >> >> > > I still want to enable the "let us just use this" mode, and I
> still
> >> >> want to
> >> >> > > avoid dependencies on infrastructure that isn't xcopy deployable.
> >> >> > > We can support this easily if we will utilize only the PHT. But
> that
> >> >> will
> >> >> > > work for local mode only. We can make use of the DHT, but then we
> need
> >> >> to
> >> >> > > provide a solution for farm wide locking. A lot of the design
> behind
> >> >> the DHT
> >> >> > > is based on always on system, because I have a requirement to kee
>
> >
>

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