geoffreyclaude commented on code in PR #83: URL: https://github.com/apache/datafusion-site/pull/83#discussion_r2198332815
########## content/blog/2025-07-10-datafusion-47.0.0.md: ########## @@ -0,0 +1,256 @@ +--- +layout: post +title: Apache DataFusion 47.0.0 Released +date: 2025-07-10 +author: PMC +categories: [ release ] +--- + +<!-- +{% comment %} +Licensed to the Apache Software Foundation (ASF) under one or more +contributor license agreements. See the NOTICE file distributed with +this work for additional information regarding copyright ownership. +The ASF licenses this file to you under the Apache License, Version 2.0 +(the "License"); you may not use this file except in compliance with +the License. You may obtain a copy of the License at +http://www.apache.org/licenses/LICENSE-2.0 +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +{% endcomment %} +--> + +<!-- see https://github.com/apache/datafusion/issues/16347 for details --> + +Weβre excited to announce the release of **Apache DataFusion 47.0.0**! This new version represents a significant +milestone for the project, packing in a wide range of improvements and fixes. You can find the complete details in the +full [changelog](https://github.com/apache/datafusion/blob/branch-47/dev/changelog/47.0.0.md). Weβll highlight the most +important changes below and guide you through upgrading. + +Note that DataFusion 47.0.0 was released in April 2025, but we are only now publishing the blog post due to +limited bandwidth in the DataFusion community. We apologize for the delay and encourage you to come help us +accelerate the next release and announcements +by [joining the community](https://datafusion.apache.org/contributor-guide/communication.html) π£. + +## Breaking Changes + +DataFusion 47.0.0 brings a few **breaking changes** that may require adjustments to your code as described in +the [Upgrade Guide](https://datafusion.apache.org/library-user-guide/upgrading.html#datafusion-47-0-0). Here are some notable ones: + +- [Upgrades to arrow-rs and arrow-parquet 55.0.0 and object_store 0.12.0](https://github.com/apache/datafusion/pull/15466): + Several APIs changed in the underlying `arrow`, `parquet` and `object_store` libraries to use a `u64` instead of usize to better support + WASM. This requires converting from `usize` to `u64` occasionally as well as changes to ObjectStore implementations such as +```Rust +impl ObjectStore { + ... + + // The range is now a u64 instead of usize + async fn get_range(&self, location: &Path, range: Range<u64>) -> ObjectStoreResult<Bytes> { + self.inner.get_range(location, range).await + } + + ... + + // the lifetime is now 'static instead of '_ (meaning the captured closure can't contain references) + // (this also applies to list_with_offset) + fn list(&self, prefix: Option<&Path>) -> BoxStream<'static, ObjectStoreResult<ObjectMeta>> { + self.inner.list(prefix) + } +} +``` +- [DisplayFormatType::TreeRender](https://github.com/apache/datafusion/issues/14914): + Implementations of `ExecutionPlan` must also provide a description in the `DisplayFormatType::TreeRender` format to + provide support for the new [tree style explains](https://datafusion.apache.org/user-guide/sql/explain.html#tree-format-default). + This can be the same as the existing `DisplayFormatType::Default`. + +## Performance Improvements + +DataFusion 47.0.0 comes with numerous performance enhancements across the board. Here are some of the noteworthy +optimizations in this release: + +- **`FIRST_VALUE` and `LAST_VALUE`:** `FIRST_VALUE` and `LAST_VALUE` functions execute much faster for data with high cardinality such as those with many groups or partitions. DataFusion 47.0.0 executes the following in **7 seconds** compared to **36 seconds** in DataFusion 46.0.0: `select id2, id4, first_value(v1 order by id2, id4) as r2 from '~/h2o_100m.parquet' group by id2, id4` (h2o.ai dataset). (PR's [#15266](https://github.com/apache/datafusion/pull/15266) + and [#15542](https://github.com/apache/datafusion/pull/15542) by [UBarney](https://github.com/UBarney)). + +- **`MIN`, `MAX` and `AVG` for Durations:** DataFusion executes aggregate queries up to 2.5x faster when they include `MIN`, `MAX` and `AVG` on `Duration` columns. + (PRs [#15322]( https://github.com/apache/datafusion/pull/15322) and [#15748](https://github.com/apache/datafusion/pull/15748) + by [shruti2522](https://github.com/shruti2522)). + +- **Short circuit evaluation for `AND` and `OR`:** DataFusion now eagerly skips the evaluation of + the right operand if the left is known to be false (`AND`) or true (`OR`) in certain cases. For complex predicates, such as those with many `LIKE` or `CASE` expressions, this optimization results in + [significant performance improvements](https://github.com/apache/datafusion/issues/11212#issuecomment-2753584617) (up to 100x in extreme cases). + (PRs [#15462](https://github.com/apache/datafusion/pull/15462) and [#15694](https://github.com/apache/datafusion/pull/15694) + by [acking-you](https://github.com/acking-you)). + +- **TopK optimization for partially sorted input:** Previous versions of DataFusion implemented early termination + optimization (TopK) for fully sorted data. DataFusion 47.0.0 extends the optimization for partially sorted data, which is common in many real-world datasets, such as time-series data sorted by day but not within each day. + (PR [#15563](https://github.com/apache/datafusion/pull/15563) by [geoffreyclaude](https://github.com/geoffreyclaude)). + +- **Disable re-validation of spilled files:** DataFusion no longer does unnecessary re-validation of temporary spill files. The validation is unnecessary and expensive as the data is known to be valid when it was written out + (PR [#15454](https://github.com/apache/datafusion/pull/15454) by [zebsme](https://github.com/zebsme)). + +## Highlighted New Features + +### Tree style explains + +In previous releases the [EXPLAIN statement] results in a formatted table +which is succinct and contains important details for implementers, but was often hard to read +especially with queries that included joins or unions having multiple children. + +[EXPLAIN statement]: https://datafusion.apache.org/user-guide/sql/explain.html + +DataFusion 47.0.0 includes the new `EXPLAIN FORMAT TREE` (default in +`datafusion-cli`) rendered in a visual tree style that is much easier to quickly +understand. + +<!-- SQL setup +create table t1(ti int) as values (1), (2), (3); +create table t2(ti int) as values (1), (2), (3); +--> + +Example of the new explain output: +```sql +> explain select * from t1 inner join t2 on t1.ti=t2.ti; ++---------------+------------------------------------------------------------+ +| plan_type | plan | ++---------------+------------------------------------------------------------+ +| physical_plan | βββββββββββββββββββββββββββββ | +| | β CoalesceBatchesExec β | +| | β -------------------- β | +| | β target_batch_size: β | +| | β 8192 β | +| | βββββββββββββββ¬ββββββββββββββ | +| | βββββββββββββββ΄ββββββββββββββ | +| | β HashJoinExec β | +| | β -------------------- ββββββββββββββββ | +| | β on: (ti = ti) β β | +| | βββββββββββββββ¬ββββββββββββββ β | +| | βββββββββββββββ΄βββββββββββββββββββββββββββββ΄ββββββββββββββ | +| | β DataSourceExec ββ DataSourceExec β | +| | β -------------------- ββ -------------------- β | +| | β bytes: 112 ββ bytes: 112 β | +| | β format: memory ββ format: memory β | +| | β rows: 1 ββ rows: 1 β | +| | ββββββββββββββββββββββββββββββββββββββββββββββββββββββββββ | +| | | ++---------------+------------------------------------------------------------+ +``` + +Example of the `EXPLAIN FORMAT INDENT` output for the same query +```sql +> explain format indent select * from t1 inner join t2 on t1.ti=t2.ti; ++---------------+----------------------------------------------------------------------+ +| plan_type | plan | ++---------------+----------------------------------------------------------------------+ +| logical_plan | Inner Join: t1.ti = t2.ti | +| | TableScan: t1 projection=[ti] | +| | TableScan: t2 projection=[ti] | +| physical_plan | CoalesceBatchesExec: target_batch_size=8192 | +| | HashJoinExec: mode=CollectLeft, join_type=Inner, on=[(ti@0, ti@0)] | +| | DataSourceExec: partitions=1, partition_sizes=[1] | +| | DataSourceExec: partitions=1, partition_sizes=[1] | +| | | ++---------------+----------------------------------------------------------------------+ +2 row(s) fetched. +``` + +Thanks to [irenjj](https://github.com/irenjj) for the initial work in PR [#14677](https://github.com/apache/datafusion/pull/14677) +and many others for completing the [followup epic](https://github.com/apache/datafusion/issues/14914) + +### SQL `VARCHAR` defaults to Utf8View + +In previous releases when a column was created in SQL the column would be mapped to the [Utf8 Arrow data type]. In this release +the SQL `varchar` columns will be mapped to the [Utf8View arrow data type] by default, which is a more efficient representation of UTF-8 strings in Arrow. + +[Utf8 Arrow data type]: https://docs.rs/arrow/latest/arrow/datatypes/enum.DataType.html#variant.Utf8 +[Utf8View arrow data type]: https://docs.rs/arrow/latest/arrow/datatypes/enum.DataType.html#variant.Utf8View + +```sql +create table foo(x varchar); +0 row(s) fetched. + +> describe foo; ++-------------+-----------+-------------+ +| column_name | data_type | is_nullable | ++-------------+-----------+-------------+ +| x | Utf8View | YES | ++-------------+-----------+-------------+ +``` + +Previous versions of DataFusion used `Utf8View` when reading parquet files and it is faster in most cases. + +Thanks to [zhuqi-lucas](https://github.com/zhuqi-lucas) for PR [#15104](https://github.com/apache/datafusion/pull/15104) + +### Tracing context propagation in spawned tasks Review Comment: Thanks for mentioning this change! You can also maybe link to the related `datafusion-contrib` repo https://github.com/datafusion-contrib/datafusion-tracing which builds upon this, otherwise the description might be a bit too abstract :) -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org