DataFusion weekly project plan (Andrew Lamb) - Jan 1, 2024

[alamb]

Follow on to Dec 25 2023:

Boilerplate Overview

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

1. Try some different ways to communicate / coordinate in the community
2. Help provide an interesting summary of what is happening in DataFusion this week

It would be great if anyone else who has plans like this for DataFusion could try to make them visible somehow as well 🙏 (feel free to copy / modify the format)

My (personal) plans for this week

• Circulate / Discuss: Draft proposal to move DataFusion to a new top level apache project #8491
• Prepare next steps for [EPIC] Unify Function Interface (remove BuiltInScalarFunction) #8045

Project Queue (list of future projects)

• Help with some more advanced pruning predicates Don't error on unknown column when pruning if predicate can still be proven false #7869 (comment)
• Writing: Blog post with DataFusion Jun - Sep 2023 #6780
• Statistics: Epic: Statistics improvements #8227 (specifically, Introduce a way to represent constrained statistics / bounds on values in Statistics #8078)

Projects I plan to prioritize reviewing / helping

• Additional work on PruningPredicate: Implement the contained method of RowGroupPruningStatistics #8669 from @yahoNanJing, and possibly Don't error on unknown column when pruning if predicate can still be proven false #7869 (comment) with @NGA-TRAN
• Memory explosion in HashJoin outputs: HashJoinStream memory tracking insufficient #7848 from @korowa
• Improve planning speed [Epic] A collection of issues to improve planning performance / speed / efficiency #5637 with @matthewmturner
• Making function packages more modular: [EPIC] Unify Function Interface (remove BuiltInScalarFunction) #8045 (looking for help)

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 am using

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

The current strategically important projects in my head are:

• Making function packages modular and easier to mix/match: [EPIC] Unify Function Interface (remove BuiltInScalarFunction) #8045
• Improving performance of high cardinality aggregation (I have dreams of working on this over Christmas break)

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 / etc.

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)

[alamb]

Review Queue:

DataFusion:

• Remove DescribeTableStmt in parser in favour of existing functionality from sqlparser-rs #8703

Arrow-rs:

• Enhance temporal kernels for Time32/64 types arrow-rs#5262

[alamb]

Review Queue:

DataFusion:

• Minor: clean up code based on Clippy #8715 (review)
• Minor: Avoid memory copy in construct window exprs #8718 (review)
• Convert Binary Operator StringConcat to Function for array_concat, array_append and array_prepend #8636 (review)
• feat: support LargeList in array_position #8714
• feat: support LargeList in array_ndims #8716
• Minor: Unbounded Output of AnalyzeExec #8717
• Implement trait based API for defining WindowUDF #8719
• support LargeList in array_prepend and array_append #8679
• [ ]

Arrow-rs:

• Enhance temporal kernels for Time32/64 types arrow-rs#5262

[alamb]

DataFusion

• Minor: Ctrl+C Termination in CLI #8739
• Move repartition_file_scans out of enable_round_robin check in EnforceDistribution rule #8731
• fix guarantees in allways_true of PruningPredicate #8732
• [CI] Improve windows machine CI test time #8730
• feat: support LargeList in array_repeat #8725

Object Store

• Fix ObjectMeta::size for range requests (#5272) arrow-rs#5276 (review)
• Retry Safe/Read-Only Requests on Timeout arrow-rs#5278

[jayzhan211]

btw, the title should be Jan 1, 2024 :)

[alamb]

DataFusion

• feat: native types in DistinctCountAccumulator for primitive types #8721
• feat: support LargeList in cardinality #8726 (review)
• Add note on using larger row group size #8745
• feat: support LargeList in cardinality #8726 (review)

[alamb]

btw, the title should be Jan 1, 2024 :)

Thank you @jayzhan211 -- I have fixed it (off by one, a classic programmer error 😆 )

[alamb]

DataFusion

• Improve Parallel Reading (CSV, JSON) / Help Wanted #8723
• Clean internal implementation of WindowUDF #8746
• feat: support largelist in array_to_string #8729
• [MINOR] CLI error handling on streaming use cases #8761
• Add http(s) support to the command line #8753
• Change ScalarValue::{List, LargeList, FixedSizedList} to take specific types rather than ArrayRef #8562
• Add ForeignKey constraint type #8566
• Minor: Use faster check for column name in schema merge #8765

[alamb]

DataFUsion:

• fix: struct field don't push down to TableScan #8774 (review)
• Minor: Fix incorrect indices for hashing struct #8775

[alamb]

Next week: #8786