is it possible to read the state of the acid database at a specific time or version?

[Anatoly Yakovenko]

is it possible to read the state of the acid database at a specific
time or version?

Thanks,
Anatoly

[Jeremy Shaw]

In theory, it is possible to replay the events one-by-one and see
every state the database was in. I do not believe there are any
timestamps stored in the events, so you would not be able to do it
based on time.

In practice, there is currently no mechanism exported for doing that.
I believe the plan is to create an 'acid-state' command-line tool that
could provide that type of functionality.

- jeremy

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[anatoly yakovenko]

It would awesome if you could support Query's on a specific version of the db. For example, i am handling paypal payment notifications, and i would be ideal for me to lookup the state of the db at the time when the payment was made and not when the notification was received.

Thanks,
Anatoly

[Petter Bergman]

I'm doing something somewhat related. I have an undo system for my web app. What i did was to create an extra layer of events for the "undo-able" portion of the state. Those events contain metadata such as timestamp, the user responsible, if the event succeeded or failed and so on. I can then go back and replay the events exept the one I want to undo. There is really nothing acid-state specific absolut this, it can be done for any haskell data.

/petter