875X improvement from RonDB 21.04.17 to 22.10.4

At Hopsworks we are working on ensuring that the online feature store will be able to perform complex join operations in real-time. This means that queries that could use data from multiple tables can be easily integrated into machine learning applications.

Today most feature stores use key-value stores like Redis and DynamoDB. These systems have no capability to issue complex join queries, if this is required the feature store will have to write complex code to handle this and this is likely to involve multiple roundtrips and thus cause unwanted latency.

Hopsworks feature store uses RonDB as its online feature store. RonDB can handle any SQL operations that MySQL can handle. Actually RonDB has even support for parallelising the join queries and pushing the filtering and joining down to the RonDB data nodes where data resides.

This means that users of the Hopsworks feature store can integrate more features from multiple feature groups in online inferencing requests. This means that things credit fraud detection can be made much more intelligent by taking more features into account in the inferencing requests.

This means that performance of real-time join queries becomes more important in RonDB. To evaluate how RonDB develops in this are I ran a set of tests using TPC-H queries from DBT3 against RonDB 21.04.17 and RonDB 22.10.4 (not released yet). I also ran tests against MySQL 8.0.35 (RonDB 22.10.4 is based on MySQL 8.0.35 with loads of added RonDB features).

The results were interesting, the improvement in Q20 was the highest I have seen in my career. The performance improved from 70 seconds to 80 milliseconds, thus an 875x speedup or 87500% improvement. Q2 had a 360x improvement. So RonDB 22.10.4 is much better equipped for more complex queries compared to RonDB 21.04. MySQL 8.0.35 had similar performance to RonDB 22.10.4 with an average of around 20% slower, this is mostly due to performance improvements in RonDB, not algorithmic changes.

When using complex queries the query optimiser tries to find an optimal plan, sometimes however better plans are available and one can add hints in the SQL query to ensure a better plan is used.

The RonDB team isn't satisfied with this however, we have realised that evaluating aggregation is also very important when the online feature store stores a time window of certain features. This means that RonDB can compute aggregate dynamically and thus provide more accurate predictions.

Early tests of some simple single table queries showed an improvement of 4-5x and we expect we will be able to get to 10-20x improvements in quite a few queries of this sort.

Merry Christmas from the RonDB team

 This year we bring a new christmas present in the form of a new release of RonDB 21.04.

It is packed with improvements, our focus has been on extending support for more platforms while at the same time increasing the quality of RonDB.

Normally the RonDB 21.04.2 would have been released in October 2021. However we had a number of support issues where we had crashes due to running very large transactions. RonDB is designed for OLTP with small to moderate sizes of transactions. However some applications makes use of foreign keys that use ON DELETE CASCADE or ON UPDATE CASCADE and these transactions can easily become hundreds of thousands of operations.

This meant changing the handling of transactions, since this was a rather large change in a stable release we wanted to ensure that we didn't introduce any quality issues. We used this opportunity to make an extensive effort in fixing all sorts of other bugs at the same time.

The new RonDB release have been tested with transaction sizes up to a number of million row operations in one transaction. We still recommend to keep transaction sizes at moderate levels since very large transactions will make heavy use of CPU and memory resources during commit and abort processing. In addition very large transactions will lock large parts of the database, thus making it more difficult for other transactions. Generally an OLTP database behaves much better if transaction sizes are kept small.

RonDB development is very much focused on supporting cloud operations. This means that our focus is on supporting Linux for production installations. Quite a few cloud vendors are now supporting ARM64 VMs in addition to the traditional Intel and AMD x86 VMs. Also Apple released a set of new ARM64 laptops lately.

Our development platform is both Mac OS X and Linux, thus it makes sense to also release RonDB on Mac OS X.

Thus we took the opportunity in RonDB 21.04.2 to provide support for ARM64 as a new platform to use for RonDB. This support covers both Linux and Mac OS X. The ARM64 support is still in beta state.

In addition we test RonDB extensively on Windows using WSL 2, the Windows subsystem to run Linux on top of Windows. Thus our Linux tarballs should work just fine to test also on Windows platforms through WSL 2.

RonDB 21.04.2 contains a large set of bug fixes that can be found in details in the RonDB documentation at https://docs.rondb.com. With these changes RonDB 21.04 contains around 100 bug fixes on top of the stable release of MySQL NDB Cluster 8.0.23 and around 15 new features.

Even more releases are developed in RonDB 21.10 and upcoming new versions of RonDB. These versions will be released when they are ready for more general consumption, but the development can be tracked on RonDB's git. If you want early access to the binary tarballs of RonDB 21.04.2 you can visit the git homepage of RonDB

Early next year we will return with benchmarks of RonDB that shows all the qualities of a LATS database.  These benchmarks will show all four qualities of a LATS database, thus low L(atency), high A(vailability), high T(hroughput) and S(calable storage).

So finally a Merry Christmas and a Happy New Year from the RonDB team.