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apache / carbondata / 1ccfb9be3fab8dfc2556541872632471d733518a
commit1ccfb9be3fab8dfc2556541872632471d733518a[log] [tgz]
authorQiangCai <qiangcai@qq.com>Mon Aug 24 16:15:54 2020 +0800
committerakashrn5 <akashnilugal@gmail.com>Tue Aug 25 21:29:06 2020 +0530
tree8c03ee08983b4569fe09a75ffde2353ab844d20f
parent9b9264523c58a958eabde3b41f778374bd473fc2 [diff]
[CARBONDATA-3958] Avoid blocking the loading task when the output queue poll timeout

Why is this PR needed?
In some cases, the CDC merge tasks are blocked when data loading uses
CarbonTableOutputFormat.getRecordWriter method. PR #3856 change the code to avoid using
CarbonTableOutputFormat.getRecordWriter, CDC merge will not happen this issue again.
But this issue maybe happen in other similar scenarios.

Because the poll method of the queue is time out in some cases, so the row batch in
the queue will not be polled again.

After the queue is full, the queue blocks the writing task puts a new batch. Even if
the queue is not full, it will also lose the row batch in the queue.

What changes were proposed in this PR?
If the output is not closed, it will poll a row batch in the loops till it gets a not
null batch.
If the output is closed, it will break the loop.

Does this PR introduce any user interface change?
No

Is any new testcase added?
No

This closes #3897
1 file changed
tree: 8c03ee08983b4569fe09a75ffde2353ab844d20f
  1. .github/
  2. assembly/
  3. bin/
  4. build/
  5. common/
  6. conf/
  7. core/
  8. dev/
  9. docs/
  10. examples/
  11. format/
  12. geo/
  13. hadoop/
  14. index/
  15. integration/
  16. licenses-binary/
  17. mv/
  18. processing/
  19. python/
  20. sdk/
  21. streaming/
  22. tools/
  23. .gitignore
  24. LICENSE
  25. NOTICE
  26. pom.xml
  27. README.md
  28. scalastyle-config.xml
README.md

Apache CarbonData is an indexed columnar data store solution for fast analytics on big data platform, e.g.Apache Hadoop, Apache Spark, etc.

You can find the latest CarbonData document and learn more at: http://carbondata.apache.org

CarbonData cwiki

Visit count: HitCount

Status

Spark2.4: Build Status Coverage Status

Features

CarbonData file format is a columnar store in HDFS, it has many features that a modern columnar format has, such as splittable, compression schema ,complex data type etc, and CarbonData has following unique features:

  • Stores data along with index: it can significantly accelerate query performance and reduces the I/O scans and CPU resources, where there are filters in the query. CarbonData index consists of multiple level of indices, a processing framework can leverage this index to reduce the task it needs to schedule and process, and it can also do skip scan in more finer grain unit (called blocklet) in task side scanning instead of scanning the whole file.
  • Operable encoded data :Through supporting efficient compression and global encoding schemes, can query on compressed/encoded data, the data can be converted just before returning the results to the users, which is “late materialized”.
  • Supports for various use cases with one single Data format : like interactive OLAP-style query, Sequential Access (big scan), Random Access (narrow scan).

Building CarbonData

CarbonData is built using Apache Maven, to build CarbonData

Online Documentation

Experimental Features

Some features are marked as experimental because the syntax/implementation might change in the future.

  1. Hybrid format table using Add Segment.
  2. Accelerating performance using MV on parquet/orc.
  3. Merge API for Spark DataFrame.
  4. Hive write for non-transactional table.

Integration

Other Technical Material

Fork and Contribute

This is an active open source project for everyone, and we are always open to people who want to use this system or contribute to it. This guide document introduce how to contribute to CarbonData.

Contact us

To get involved in CarbonData:

About

Apache CarbonData is an open source project of The Apache Software Foundation (ASF).