DataFusion weekly project plan (Andrew Lamb) - March 4, 2024

[alamb]

Follow on to Feb 26, 2024.

Note I am traveling this week and will have limited bandwidth so I will not be as responsive as normal

It would be great for other contributors to DataFusion who plan non trivial work could try to make them visible somehow as well 🙏 (feel free to copy / modify the format)

My Highlights from Last Week

• The large scale "extract scalar functions from the core" is well under way [Epic] Port BuiltInFunctons to datafusion-functions-* crates #9285
• Comet blog draft was done [Website] Add Blog about Comet Donation arrow-site#479
• Revised the proposal for a new top level project and started a vote thread: [DISCUSS] Move Apache Arrow Datafusion to a new top level Apache project #6475
• Agenda for DataFusion meetup 2024 is looking good UPDATE: VENUE IS FULL Invitation: Mar 25, 2024 DataFusion meetup before the DataCouncil March 2024 in Austin TX #8522
• ScalarUDF::simplify API ready (thanks @jayzhan211!) Add a ScalarUDFImpl::simplfy() API, move SimplifyInfo et al to datafusion_expr #9304

My (personal) goals for this project

1000 projects are built using DataFusion 📈

My (personal) plans for this week

• SIGMOD paper feedback (I plan to work on this the week of March 4, 2024): Finalize SIGMOD 2024 paper ~(if accepted)~ #8373 )
• Keep up with reviews backlog 🏃
• File a ticket to track remaing work for Recursive CTEs and close out Add support for recursive CTEs #462

Project Queue (list of future projects)

Projects I plan to help actively help review / plan

• Support "A column is known to be entirely NULL" in PruningPredicate #9171 with @appletreeisyellow (we need this for InfluxDB)
• Improved planning speed [Epic] A collection of issues to improve planning performance / speed / efficiency #5637 with @matthewmturner

Algorithm for (my) prioritizing PR reviews

Note there are many committers who can and do review and merge PRs, so this is not the priorities of the project as a whole, just the approximate algorithm I use to prioritize my own time

Priority:

1. Bug fixes (where something is just incorrect), especially regressions (where it used to work and now does not)
2. Improvements directly related to features needed for InfluxDB (my employer)
3. Documentation and test improvements (I view these as very strategically important)
4. PRs that I think are strategically important
5. Other new features / additions to functionality (note this is the lowest)

The top strategically important projects in my head are:

• Anything that makes it easier to use DataFusion as a user (docs, examples, better APIs, etc), including Getting started guide for new users (who want to use DataFusion in their project)
• Anything that improves DataFusion's quality such as bug fixes, and improved / expanded tests, etc
• Making function packages modular and easier to mix/match: [EPIC] Unify Function Interface (remove BuiltInScalarFunction) #8045
• Improving performance of aggregation - especially high cardinality groupings, where we still lag state of the art by 2x

Thus, if you are interested in contributing to DataFusion and are interested in a fast turn around time I would recommend looking into bug fixes / test improvements / documentation or the projects named above

If you propose adding new functionality, the review cycle will likely be longer. You can make it a shorter cycle by looking at the comments on other recent PRs and following the same model (e.g. ensure there are tests in sqllogictest for example, the CI passes, includes documentation, etc)

Background

The idea of this ticket is make my plans for DataFusion visible, largely for my own personal organizational needs, but also to:

1. Communicate / coordinate in the community
2. Help provide an interesting summary of what is happening in DataFusion this week

[alamb]

I am returning home and will be working through the review backlog

Current queue:

DataFusion:

• Add to_unixtime function #9077
• Port ArrayHas family to functions-array #9496
• Add /benchmark github command to comparison benchmark between base and pr commit #9461
• Add example for FunctionFactory #9482
• Move date_part, date_trunc, date_bin functions to datafusion-functions #9435

Arow-rs

• Support dictionary encoding in structures for FlightDataEncoder, add documentation for arrow_flight::encode::Dictionary arrow-rs#5488 (review)

Follow DataFusion

• [ ]

[alamb]

DataFusion:

• Systematic Configuration in 'Create External Table' and 'Copy To' Options #9382
• Implement spilling for PartialSortExec #9469
• Support ORDER BY in AggregateUDF #9249

Arrow

• feat: initial support string_view and binary_view, supports layout and basic construction + tests arrow-rs#5481
• Remove internal buffering from AsyncArrowWriter (#5484) arrow-rs#5485
• Add size statistics to ParquetMetaData introduced in PARQUET-2261 arrow-rs#5486

[alamb]

Next week; #9555