Hi there, Sorry for the delayed response but this went to my spam. Are you planning on open sourcing this UDF? I’d be happy to do a code review and give you some suggestions. Could you explain more about the use case however as I am totally unfamiliar with this. Thanks! — Charles
> On Oct 4, 2026, at 14:45, richard van der koppen <[email protected]> > wrote: > > Hi Drill Developers/experts, > > I hope you are all doing well. > > I have been working on a geospatial architecture use case for a while now, > researching the best way to handle large-scale Dutch coordinate > transformations directly inside Apache Drill. Next week, I am planning to > test my first working prototype / MVP for a custom Java Scalar UDF > (rd_to_wgs84). > The goal of this UDF is to perform high-performance, on-the-fly > transformations from the Dutch Rijksdriehoekscoördinaten (RD New / > Amersfoort, EPSG:28992) to global WGS84 coordinates (Latitude/Longitude, > EPSG:4326). > > To maximize performance and avoid external GIS library overhead during > runtime code generation, the MVP will implement the official > Bessel-to-WGS84 polynomial regression formulas directly into the eval() > method using primitive doubles, Netty DrillBuf writes, and a VarCharHolder > output. > > Since Drill UDFs operate on a very specific subset of Java and rely heavily > on internal scalar replacement, I want to make sure my implementation > strictly adheres to Drill's compilation mechanics and memory management > rules. > > Once the MVP and the Maven project are up and running next week, would > anyone with experience in Drill's query engine internals and code > generation be open to reviewing the Java code? I am planning to publish the > final project as an open-source repository on GitHub to help the geospatial > data engineering community. > > Any guidance or interest in doing a quick code review would be highly > appreciated! Feel free to send me a private message at this email address, > and we can discuss things privately between ourselves. > > Best regards, > > M.D
