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From "Zheng, Kai" <>
Subject RE: [DISCUSS] CarbonData incubation proposal
Date Thu, 19 May 2016 14:53:49 GMT
This sounds good to have, as a nice complement to the existing data formats. Thanks for the

Non-binding +1.


-----Original Message-----
From: Jean-Baptiste Onofré [] 
Sent: Wednesday, May 18, 2016 8:53 PM
Subject: [DISCUSS] CarbonData incubation proposal

Hi all,

We would like to discuss about a new proposal for the incubator: CarbonData.

CarbonData is a new Apache Hadoop native file format for faster interactive query using advanced
columnar storage, index, compression and encoding techniques to improve computing efficiency,
in turn it will help speedup queries an order of magnitude faster over PetaBytes of data.

The proposal is included below and also available on the wiki:

Please, provide any feedback or comment.

Thanks !

= Apache CarbonData =

== Abstract ==

Apache CarbonData is a new Apache Hadoop native file format for faster interactive query using
advanced columnar storage, index, compression and encoding techniques to improve computing
efficiency, in turn it will help speedup queries an order of magnitude faster over PetaBytes
of data.

CarbonData github address:

== Backgrounad ==

Huawei is an ICT solution provider, we are committed to enhancing customer experiences for
telecom carriers, enterprises, and consumers on big data, In order to satisfy the following
customer requirements, we created a new Hadoop native file format:

  * Support interactive OLAP-style query over big data in seconds.
  * Support fast query on individual record which require touching all fields.
  * Fast data loading speed and support incremental load in period of minutes.
  * Support HDFS so that customer can leverage existing Hadoop cluster.
  * Support time based data retention.

Based on these requirements, we investigated existing file formats in the Hadoop eco-system,
but we could not find a suitable solution that satisfying requirements all at the same time,
so we start designing CarbonData.

== Rationale ==

CarbonData contains multiple modules, which are classified into two

  1. CarbonData File Format: which contains core implementation for file format such as columnar,index,dictionary,encoding+compression,API
for reading/writing etc.
  2. CarbonData integration with big data processing framework such as Apache Spark, Apache
Hive etc. Apache Beam is also planned to abstract the execution runtime.

=== CarbonData File Format ===

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:

==== Indexing ====

In order to support fast interactive query, CarbonData leverage indexing technology to reduce
I/O scans. CarbonData files stores data along with index, the index is not stored separately
but the CarbonData file itself contains the index. In current implementation, CarbonData supports
3 types of indexing:

1. Multi-dimensional Key (B+ Tree index)
  The Data block are written in sequence to the disk and within each data blocks each column
block is written in sequence. Finally, the metadata block for the file is written with information
about byte positions of each block in the file, Min-Max statistics index and the start and
end MDK of each data block. Since, the entire data in the file is in sorted order, the start
and end MDK of each data block can be used to construct a B+Tree and the file can be logically
 represented as a 
B+Tree with the data blocks as leaf nodes (on disk) and the remaining
non-leaf nodes in memory.
2. Inverted index
  Inverted index is widely used in search engine. By using this index, it helps processing/query
engine to do filtering inside one HDFS block. 
Furthermore, query acceleration for count distinct like operation is made possible when combining
bitmap and inverted index in query time.
3. MinMax index
  For all columns, minmax index is created so that processing/query engine can skip scan that
is not required.

==== Global Dictionary ====

Besides I/O reduction, CarbonData accelerates computation by using global dictionary, which
enables processing/query engines to perform all processing on encoded data without having
to convert the data (Late Materialization). We have observed dramatic performance improvement
for OLAP analytic scenario where table contains many columns in string data type. The data
is converted back to the user readable form just before processing/query engine returning
results to user.

==== Column Group ====

Sometimes users want to perform processing/query on multi-columns in one table, for example,
performing scan for individual record in troubleshooting scenario. In this case, row format
is more efficient than columnar format since all columns will be touched by the workload.

To accelerate this, CarbonData supports storing a group of column in row format, so data in
column group is stored together and enable fast retrieval.

==== Optimized for multiple use cases ====

CarbonData indices and dictionary is highly configurable. To make storage optimized for different
use cases, user can configure what to index, so user can decide and tune the format before
loading data into CarbonData.

For example

|| Use Case || Supporting Features ||
|| Interactive OLAP query || Columnar format, Multi-dimensional Key (B+
Tree index), Minmax index, Inverted index ||
|| High throughput scan || Global dictionary, Minmax index || Low 
|| latency point query || Multi-dimensional Key (B+ Tree index),
Partitioning ||
|| Individual record query || Column group, Global dictionary ||

=== BigData Processing Framework Integration ===

  * CarbonData provides InputFormat/OutputFormat interfaces for Reading/Writing data from
the CarbonData files and at the same time provides abstract API for processing data stored
as Carbondata format with data processing framework.
  * CarbonData provides deep integration with Apache Spark including predicate push down,
column pruning, aggregation push down etc. So users can use Spark SQL to connect and query
from CarbonData.
  * CarbonData can integrate with various big data Query/Processing framework on Hadoop eco-system
such as Apache Spark,Apache Hive etc.


== Initial Goals ==

Our initial goals are to bring CarbonData into the ASF, transition internal engineering processes
into the open, and foster a collaborative development model according to the "Apache Way".

== Current Status ==

CarbonData is production ready and already provide a large set of features.
The current license is already Apache 2.0.

== Meritocracy ==

We intend to radically expand the initial developer and user community by running the project
in accordance with the "Apache Way". Users and new contributors will be treated with respect
and welcomed. By participating in the community and providing quality patches/support that
move the project forward, they will earn merit. They also will be encouraged to provide non-code
contributions (documentation, events, community management, etc.) and will gain merit for
doing so. Those with a proven support and quality track record will be encouraged to become

== Community ==

If CarbonData is accepted for incubation, the primary initial goal is to build a large community.
We really trust that CarbonData will become a key project for big data column-like platforms,
and so, we bet on a large community of users and developers.

== Known Risks ==

Development has been sponsored mostly by a one company.For the project to fully transition
to the Apache Way governance model, development must shift towards the meritocracy-centric
model of growing a community of contributors balanced with the needs for extreme stability
and core implementation coherency.

== Orphaned products ==

Huawei is fully committed CarbonData. Moreover, Huawei has a vested interest in making CarbonData
succeed by driving its close integration with sister ASF projects. We expect this to further
reduces the risk of orphaning the product.

== Inexperience with Open Source ==

Huawei has been developing and using open source software since a long time. Additionally,
several ASF veterans agreed to mentor the project and are listed in this proposal. The project
will rely on their guidance and collective wisdom to quickly transition the entire team of
initial committers towards practicing the Apache Way.

== Reliance on Salaried Developers ==

Most of the contributors are paid to work in big data space. While they might wander from
their current employers, they are unlikely to venture far from their core expertises and thus
will continue to be engaged with the project regardless of their current employers.

== An Excessive Fascination with the Apache Brand ==

While we intend to leverage the Apache ‘branding’ when talking to other projects as testament
of our project’s ‘neutrality’, we have no plans for making use of Apache brand in press
releases nor posting billboards advertising acceptance of CarbonData into Apache Incubator.

== Initial Source ==

== External Dependencies ==

All external dependencies are licensed under an Apache 2.0 license or Apache-compatible license.
As we grow the Carbondata community we will configure our build process to require and validate
all contributions and dependencies are licensed under the Apache 2.0 license or are under
an Apache-compatible license.

  * Apache Spark
  * Apache Hadoop
  * Apache Maven
  * Apache Commons
  * Apache Log4j
  * Apache Thrift
  * Apache Zookeeper
  * Scala
  * Snappy
  * Kettle (Pentaho)
  * Eigenbase
  * Fastutil
  * GSON
  * Jmockit
  * Junit

== Required Resources ==

=== Mailing lists ===

  * (moderated subscriptions)

=== Git Repository ===


=== Issue Tracking ===

  * JIRA Project CarbonData (CarbonData)

=== Initial Committers ===

  * Liang Chenliang
  * Jean-Baptiste Onofré
  * Henry Saputra
  * Uma Maheswara Rao G
  * Jenny MA
  * Jacky Likun
  * Vimal Das Kammath
  * Jarray Qiuheng

=== Affiliations ===

  * Huawei: Liang Chenliang
  * Talend: Jean-Baptiste Onofré
  * Ebay: Henry Saputra
  * Intel: Uma Maheswara Rao G

=== Sponsors ===

=== Champion ===

  * Jean-Baptiste Onofré - Apache Member

=== Mentors ===

  * Henry Saputra (eBay)
  * Jean-Baptiste Onofré (Talend)
  * Uma Maheswara Rao G (Intel)

=== Sponsoring Entity ===

The Apache Incubator

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