Hi,

Just want to share something I am working on in 3.2 if these matter.


  *   Shuffled hash join improvement (SPARK-32461)
     *   This is one of release notes JIRAs in 3.1, and major thing left is 
sort-based fallback and code-gen for FULL OUTER join.
  *   Join and aggregation code-gen (SPARK-34287 and more to create)
     *   Add code-gen for all join types of sort merge join, object hash 
aggregation and sort aggregation.
  *   Write Hive/Presto-compatible bucketed table (SPARK-19256)
     *   This is a long-standing issue and we made progress on plan during 3.1 
development. We ideally want to finish the feature in 3.2.

For most of features here, we already developed internally and rolled out to 
production.

Thanks,
Cheng Su

From: Dongjoon Hyun <dongjoon.h...@gmail.com>
Date: Friday, February 26, 2021 at 4:06 PM
To: Hyukjin Kwon <gurwls...@gmail.com>
Cc: huaxin gao <huaxin.ga...@gmail.com>, Xiao Li <gatorsm...@gmail.com>, dev 
<dev@spark.apache.org>
Subject: Re: Apache Spark 3.2 Expectation

Sure, thank you, Hyukjin.

Bests,
Dongjoon.


On Fri, Feb 26, 2021 at 4:01 PM Hyukjin Kwon 
<gurwls...@gmail.com<mailto:gurwls...@gmail.com>> wrote:
I have an idea which I'll send an email to discuss next or a week after the 
next week. I did not have enough bandwidth to drive both together at the same 
time. I would appreciate if we have some more time for 3.2.

In addition, It would also be great if we follow the schedule and catch 
potential blockers quickly during QA instead of when we cut RCs. That will 
considerably speed up the process and make it on time.

Thanks.

On Sat, 27 Feb 2021, 06:00 Dongjoon Hyun, 
<dongjoon.h...@gmail.com<mailto:dongjoon.h...@gmail.com>> wrote:
Thank you for sharing your plan, Huaxin!

Bests,
Dongjoon.


On Fri, Feb 26, 2021 at 12:20 PM huaxin gao 
<huaxin.ga...@gmail.com<mailto:huaxin.ga...@gmail.com>> wrote:
Thanks Dongjoon and Xiao for the discussion. I would like to add Data Source V2 
Aggregate push down to the list. I am currently working on JDBC Data Source V2 
Aggregate push down, but the common code can be used for the file based V2 Data 
Source as well. For example, MAX and MIN can be pushed down to Parquet and Orc, 
since they can use statistics information to perform these operations 
efficiently. Quite a few users are interested in this Aggregate push down 
feature and the preliminary performance test for JDBC Aggregate push down is 
positive. So I think it is a valuable feature to add for Spark 3.2.

Thanks,
Huaxin

On Fri, Feb 26, 2021 at 11:13 AM Xiao Li 
<gatorsm...@gmail.com<mailto:gatorsm...@gmail.com>> wrote:
Thank you, Dongjoon, for initiating this discussion. Let us keep it open. It 
might take 1-2 weeks to collect from the community all the features we plan to 
build and ship in 3.2 since we just finished the 3.1 voting.

3. +100 for Apache Spark 3.2.0 in July 2021. Maybe, we need `branch-cut` in 
April because we took 3 month for Spark 3.1 release.

TBH, cutting the branch this April does not look good to me. That means, we 
only have one month left for feature development of Spark 3.2. Do we have 
enough features in the current master branch? If not, are we able to finish 
major features we collected here? Do they have a timeline or project plan?

Xiao

Dongjoon Hyun <dongjoon.h...@gmail.com<mailto:dongjoon.h...@gmail.com>> 
于2021年2月26日周五 上午10:07写道:
Thank you, Mridul and Sean.

1. Yes, `2017` was a typo. Java 17 is scheduled September 2021. And, of course, 
it's a nice-to-have status. :)

2. `Push based shuffle and disaggregated shuffle`. Definitely. Thanks for 
sharing,

3. +100 for Apache Spark 3.2.0 in July 2021. Maybe, we need `branch-cut` in 
April because we took 3 month for Spark 3.1 release.
    Let's update our release roadmap of the Apache Spark website.

> I'd roughly expect 3.2 in, say, July of this year, given the usual cadence. 
> No reason it couldn't be a little sooner or later. There is already some good 
> stuff in 3.2 and will be a good minor release in 5-6 months.

Bests,
Dongjoon.



On Thu, Feb 25, 2021 at 9:33 AM Sean Owen 
<sro...@gmail.com<mailto:sro...@gmail.com>> wrote:
I'd roughly expect 3.2 in, say, July of this year, given the usual cadence. No 
reason it couldn't be a little sooner or later. There is already some good 
stuff in 3.2 and will be a good minor release in 5-6 months.

On Thu, Feb 25, 2021 at 10:57 AM Dongjoon Hyun 
<dongjoon.h...@gmail.com<mailto:dongjoon.h...@gmail.com>> wrote:
Hi, All.

Since we have been preparing Apache Spark 3.2.0 in master branch since December 
2020, March seems to be a good time to share our thoughts and aspirations on 
Apache Spark 3.2.

According to the progress on Apache Spark 3.1 release, Apache Spark 3.2 seems 
to be the last minor release of this year. Given the timeframe, we might 
consider the following. (This is a small set. Please add your thoughts to this 
limited list.)

# Languages

- Scala 2.13 Support: This was expected on 3.1 via SPARK-25075 but slipped out. 
Currently, we are trying to use Scala 2.13.5 via SPARK-34505 and investigating 
the publishing issue. Thank you for your contributions and feedback on this.

- Java 17 LTS Support: Java 17 LTS will arrive in September 2017. Like Java 11, 
we need lots of support from our dependencies. Let's see.

- Python 3.6 Deprecation(?): Python 3.6 community support ends at 2021-12-23. 
So, the deprecation is not required yet, but we had better prepare it because 
we don't have an ETA of Apache Spark 3.3 in 2022.

- SparkR CRAN publishing: As we know, it's discontinued so far. Resuming it 
depends on the success of Apache SparkR 3.1.1 CRAN publishing. If it succeeds 
to revive it, we can keep publishing. Otherwise, I believe we had better drop 
it from the releasing work item list officially.

# Dependencies

- Apache Hadoop 3.3.2: Hadoop 3.2.0 becomes the default Hadoop profile in 
Apache Spark 3.1. Currently, Spark master branch lives on Hadoop 3.2.2's shaded 
clients via SPARK-33212. So far, there is one on-going report at YARN 
environment. We hope it will be fixed soon at Spark 3.2 timeframe and we can 
move toward Hadoop 3.3.2.

- Apache Hive 2.3.9: Spark 3.0 starts to use Hive 2.3.7 by default instead of 
old Hive 1.2 fork. Spark 3.1 removed hive-1.2 profile completely via 
SPARK-32981 and replaced the generated hive-service-rpc code with the official 
dependency via SPARK-32981. We are steadily improving this area and will 
consume Hive 2.3.9 if available.

- K8s Client 4.13.2: During K8s GA activity, Spark 3.1 upgrades K8s client 
dependency to 4.12.0. Spark 3.2 upgrades it to 4.13.2 in order to support K8s 
model 1.19.

- Kafka Client 2.8: To bring the client fixes, Spark 3.1 is using Kafka Client 
2.6. For Spark 3.2, SPARK-33913 upgraded to Kafka 2.7 with Scala 2.12.13, but 
it was reverted later due to Scala 2.12.13 issue. Since KAFKA-12357 fixed the 
Scala requirement two days ago, Spark 3.2 will go with Kafka Client 2.8 
hopefully.

# Some Features

- Data Source v2: Spark 3.2 will deliver much richer DSv2 with Apache Iceberg 
integration. Especially, we hope the on-going function catalog SPIP and 
up-coming storage partitioned join SPIP can be delivered as a part of Spark 3.2 
and become an additional foundation.

- Columnar Encryption: As of today, Apache Spark master branch supports 
columnar encryption via Apache ORC 1.6 and it's documented via SPARK-34036. 
Also, upcoming Apache Parquet 1.12 has a similar capability. Hopefully, Apache 
Spark 3.2 is going to be the first release to have this feature officially. Any 
feedback is welcome.

- Improved ZStandard Support: Spark 3.2 will bring more benefits for ZStandard 
users: 1) SPARK-34340 added native ZSTD JNI buffer pool support for all IO 
operations, 2) SPARK-33978 makes ORC datasource support ZSTD compression, 3) 
SPARK-34503 sets ZSTD as the default codec for event log compression, 4) 
SPARK-34479 aims to support ZSTD at Avro data source. Also, the upcoming 
Parquet 1.12 supports ZSTD (and supports JNI buffer pool), too. I'm expecting 
more benefits.

- Structure Streaming with RocksDB backend: According to the latest update, it 
looks active enough for merging to master branch in Spark 3.2.

Please share your thoughts and let's build better Apache Spark 3.2 together.

Bests,
Dongjoon.

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