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Consensus Team Update

· 3 min read
Damian Nadales

High level summary

During the past two weeks, the consensus team merged improvements to the monadic cursor API that was needed to implement LMDB range reads, which is in turn required for the implementation of the UTxO HD feature. We added tables to several tests in for the UTxO HD feature, which increases our confidence in the correctness of the prototype. The mempool property tests are close to being completed. Also, we finished the LSM tree tuning algorithm.

On the Genesis front we started simplifying the BlockFetch logic with CSJ-specific workloads in mind.

We are also documenting the Block Diffusion Pipelining feature, and added a high-level overview of consensus to the top level documentation of ouroboros-network.


UTxO HD prototype

We merged the implementation of a monadic cursor API (#1)) which was needed to solve a bug with LMDB range-reads. After this PR was merged, we focused on bridging the gap between the lmdb-simple interface and consensus by facilitating using lmdb-simple's cursor API without Serialise constraints (#3).

We refactored the backing store property tests to use quickcheck-lockstep (#4081).

We added tables to the mock ledger in the UTxO-HD feature branch (#4184). Every test that used to run with SimpleBlocks now uses tables. This will enable us to exercise the UTxO HD mempool integration by leveraging the existing mempool property-tests. The new state-machine property-tests are still needed for testing the parallel behaviour of the mempool.

Our work on the mempool state-machine tests revealed the need for improvements in the quickcheck-state-machine library. Parallel testing assumed that the state machine did not have access to mutable references. However, the mempool tests require the use of such mutable references for mocking the ledger interface. As a result, our parallel tests were failing with rather obscure messages. @Jasagredo submitted a pull request (#12) that allows for new mutable references to be created at each run of the state machine.

Backing store property tests

LSM tree implementation

We finished the LSM Tree tuning algorithm. We are currently tidying up the code and gathering results (i.e., plots and their interpretation).

CSJ prototype

We started simplifying the BlockFetch logic with CSJ-specific workloads in mind.

New VRF and KES crypto integration

Started working on supporting new version of StandardCrypto which uses compact KES and batched VRF (#4151).

Technical debt

We reviewed the existing state of the Block Diffusion Pipelining document. We are now working on the "Implementation" section (#4020).

Fostering collaboration

We cleared up our understanding of the error dynamics of forecasting (#4146 and #4174).

We submitted a pull request that adds an overview of consensus to the top level documentation of ouroboros-network (#4197). This overview describes the consensus components and adds a hyperlinked map to the modules documentation.