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From Jan Lehnardt <>
Subject Re: [DISCUSS] Reduce on FDB take 3
Date Tue, 21 Jul 2020 12:45:35 GMT
Heya Garren an Bob,

this looks really nice. I remember when this was a twinkle in our
planning eyes. Seeing the full thing realised is very very cool.

I’m additionally impressed by the rather pretty and clean code.
This doesn’t have to to be hard :)

Looking forward to see this in action.


> On 21. Jul 2020, at 14:01, Garren Smith <> wrote:
> Hi All
> We have a new reduce design for FoundationDB and we think this one will
> work.
> Recently I proposed a simpler reduce design [1] and at the same time, Bob
> (rnewson) looked at implementing a B+tree [2], called ebtree, on top of
> FoundationDB. The b+tree implementation has turned out really nicely, the
> code is quite readable and works really well. I would like to propose that
> instead of using the simpler reduce design I mentioned in the previous
> email, we rather go with a reduce implementation on top of ebtree. The big
> advantage of ebtree is that it allows us to keep the behaviour of CouchDB
> 3.x.
> We have run some basic performance tests on the Cloudant performance
> clusters and so far the performance is looking quite good and performs very
> similar to my simpler reduce work.
> There is an unknown around the ebtree Order value. The Order is the number
> of key/values stored for a node. We need to determine the optimal order
> value for ebtree so that it doesn't exceed FoundationDB's key/value limits
> and still performs well. This is something we will be looking at as we
> finish up the reduce work. The work in progress for the reduce PR is
> A great thanks to Bob for implementing the B+tree. I would love to hear
> your thoughts or questions around this?
> Cheers
> Garren
> [1]
> [2]
> [3]

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