DataFusion weekly project plan (Andrew Lamb) - March 11, 2024

[alamb]

Follow on to #9453

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

• ScalarUDF::simplify API merged Add a ScalarUDFImpl::simplfy() API, move SimplifyInfo et al to datafusion_expr #9304 (thanks @jayzhan22)
• Pluggable handler for CREATE FUNCTIONL Add plugable handler for CREATE FUNCTION #9333 (thanks @milenkovicm)
• DataFusion Comet blog published: https://arrow.apache.org/blog/2024/03/06/comet-donation/
• Move of DataFusion to a top level Apache project was approved by the community: [DISCUSS] Move Apache Arrow Datafusion to a new top level Apache project #6475
• Large scale "extract scalar functions from the core" continues at good pace way [Epic] Port BuiltInFunctons to datafusion-functions-* crates #9285

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 )

Project Queue (list of future projects)

Projects I plan to help actively help review / plan

• [EPIC] Implement StringViewArray and BinaryViewArray arrow-rs#5374
• [Epic] Port BuiltInFunctons to datafusion-functions-* crates #9285
• Support "A column is known to be entirely NULL" in PruningPredicate #9171 with @appletreeisyellow (we need this for InfluxDB)
• Supporting using parallel parquet writer outside of Datafusion query execution #9493 with @wiedld

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]

DataFusion:

• Systematic Configuration in 'Create External Table' and 'Copy To' Options #9382
• Move Array specific rewrites to datafusion_functions_array AnalyzerRule #9557

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 DataType::ListView and DataType::LargeListView arrow-rs#5493
• Implement MultiPartStore for InMemory arrow-rs#5495

Sqlparser-rs

• Add identifier quote style to Dialect trait datafusion-sqlparser-rs#1170

[alamb]

DataFusion:

• Add /benchmark github command to comparison benchmark between base and pr commit #9461
• support unprefixed config format options #9594 (review)
• Initial support LogicalPlan to SQL String #9596
• Support "A column is known to be entirely NULL" in PruningPredicate #9223
• feat: implement aggregation and subquery plans to SQL #9606
• Make COPY TO align with CREATE EXTERNAL TABLE #9604
• Window Linear Mode use smaller buffers #9597
• 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
• Replace AsyncWrite with Upload trait and rename MultiPartStore to MultipartStore (#5458) arrow-rs#5500
• Add size statistics to ParquetMetaData introduced in PARQUET-2261 arrow-rs#5486

Sqlparser

• Support MySQL UNIQUE table constraint datafusion-sqlparser-rs#1164
• Support named windows in OVER (window_definition) clause datafusion-sqlparser-rs#1166

[alamb]

• Update Arrow/Parquet to 51.0.0, tonic to 0.11 #9613 (review)

[alamb]

#9675 tracks next week