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From "Gangumalla, Uma" <>
Subject Re: [VOTE] Accept Tephra into the Apache Incubator
Date Tue, 08 Mar 2016 01:23:49 GMT
+1 (non binding)


On 3/3/16, 5:29 PM, "Poorna Chandra" <> wrote:

>Hi All,
>Tephra proposal was sent out for discussion last week. The proposal is
>available at
>Please vote to accept Tephra into the Apache Incubator. The vote will be
>open for the next 72 hours.
>[ ] +1 Accept Tephra as an Apache Incubator podling.
>[ ] +0 Abstain.
>[ ] -1 Don¹t accept Tephra as an Apache Incubator podling because ...
>= Abstract =
>Tephra is a system for providing globally consistent transactions on
>top of Apache HBase and other storage engines.
>= Proposal =
>Tephra is a transaction engine for distributed data stores like Apache
>It provides ACID semantics for concurrent data operations that span over
>boundaries in HBase using Optimistic Concurrency Control.
>= Background =
>HBase provides strong consistency with row- or region-level ACID
>operations. However, it sacrifices cross-region and cross-table
>consistency in favor of scalability. This trade-off requires application
>developers to handle  the complexity of ensuring consistency when their
>modifications span region boundaries. By providing support for global
>transactions that span regions, tables, or multiple RPCs,
>Tephra simplifies application development on top of HBase, without a
>significant impact on performance or scalability for many workloads.
>Tephra leverages HBase¹s native data versioning to provide multi-versioned
>concurrency control (MVCC) for transactional reads and writes.
>With MVCC capability, each transaction sees its own consistent ³snapshot²
>data, providing snapshot isolation of concurrent transactions.
>MVCC along with conflict detection and handling enables Optimistic
>Tephra consists of three main components:
> * Transaction Server ­ maintains global view of transaction state,
>   new transaction IDs and performs conflict detection;
> * Transaction Client ­ coordinates start, commit, and rollback of
>transactions; and
> * Transaction Processor Coprocessor ­ applies filtering to the data read
>   on a given transaction¹s state) and cleans up any data from old
>   (no longer visible) transactions.
>Although Tephra only supports HBase now, it can be extended to support
>transactions on any store that has multi-versioning and rollback
>support. The transactions
>can span over multiple stores and storage paradigms.
>= Rationale =
>Tephra has simple abstractions which can be used by an application to
>add transaction support over HBase. By abstracting away transaction
>handling using Tephra, the application is freed of
>transaction logic, and the application developer can focus on the use
>Also, Tephra can be extended to support transactions on data sources other
>than HBase.
>By making Tephra an Apache open source project, we believe that there will
>be wider adoption and more opportunities for Tephra to be integrated
>into other Apache projects.
>= Current Status =
>Tephra was built at Cask Data Inc. initially as part of
>open-source framework Cask Data Application Platform (CDAP)
>It was later converted into an independent open source project with
>Apache 2.0 License [[]].
>Tephra is used in CDAP as the transaction engine. As part of CDAP, Tephra
>has been deployed at multiple companies.
>Apache Phoenix is using Tephra as transaction engine in the next release.
>== Meritocracy ==
>Our intent with this incubator proposal is to start building a diverse
>developer community around Tephra following the Apache meritocracy model.
>Since Tephra was initially developed in early 2013, we have had fast
>adoption and contributions within Cask Data. We are looking forward to
>new contributors. We wish to build a community based on Apache's
>meritocracy principles, working with those who contribute significantly to
>the project and welcoming them to be committers both during the incubation
>process and beyond.
>== Community ==
>Core developers of Tephra are at Cask Data. Recently the developer
>has expanded to include folks from Apache Phoenix. We hope to extend our
>contributor base significantly and we will invite all who are interested
>in working on distributed transaction engine.
>== Core Developers ==
>A few engineers from Cask Data and outside have developed Tephra:
>Andreas Neumann, Terence Yim, Gary Helmling, Andrew Purtell and
>Poorna Chandra.
>== Alignment ==
>The ASF is the natural choice to host the Tephra project as its goal of
>encouraging community-driven open source projects fits with our vision for
>Additionally, many other projects with which we are familiar and expect
>Tephra to integrate with, such as Phoenix, Zookeeper, HDFS, log4j, and
>mentioned in the External Dependencies section are Apache projects, and
>Tephra will benefit by close proximity to them.
>= Known Risks =
>== Orphaned Products ==
>There is very little risk of Tephra being orphaned, as it is a key part of
>Cask Data¹s products. The core Tephra developers plan to continue to work
>on Tephra, and Cask Data has funding in place to support their efforts
>going forward.
>Also with Phoenix using Tephra for transactions, Phoenix developers are
>keen on contributing to Tephra.
>== Inexperience with Open Source ==
>Several of the core developers have experience with open source
>development. Andreas Neumann is an Apache committer for Oozie and Twill.
>Terence Yim is an Apache committer for Helix and Twill. Poorna Chandra
>is an Apache committer for Twill. Gary Helmling is a committer for
>Apache Twill and a committer and PMC member for Apache HBase.
>James Taylor is PMC chair for Apache Phoenix, PMC member of Apache
>and an IPMC member.
>== Homogeneous Developers ==
>The current core developers are all Cask Data employees. However, we
>intend to establish a developer community that includes independent and
>corporate contributors. We are encouraging new contributors via our
>lists, public presentations, and personal contacts, and we will continue
>do so.
>Apache Phoenix developers have already contributed several patches to
>and have expressed interest in becoming long term contributors.
>== Reliance on Salaried Developers ==
>Currently, these developers are paid to work on Tephra. Once the project
>built a community, we expect to attract committers, developers and
>other than the current core developers. However, because Cask Data
>products use Tephra internally, the reliance on salaried developers is
>unlikely to change, at least in the near term.
>== Relationships with Other Apache Products ==
>Tephra is deeply integrated with Apache projects. Tephra provides
>over Apache HBase, and uses Apache Twill and Apache Zookeeper for
>A number of other Apache projects are Tephra dependencies, and are
>listed in the External Dependencies section.
>In addition, Apache Phoenix is using Tephra as the transaction engine.
>== An Excessive Fascination with the Apache Brand ==
>While we respect the reputation of the Apache brand and have no doubt that
>it will attract contributors and users, our interest is primarily to give
>Tephra a solid home as an open source project following an established
>development model. We have also given additional reasons in the Rationale
>and Alignment sections.
>= Documentation =
>The current documentation for Tephra is at
>= Initial Source =
>Tephra codebase is currently hosted at
>= Source and Intellectual Property Submission Plan =
>Tephra codebase is currently licensed under Apache 2.0 license.
>Cask Data owns the trademark for "Tephra". As part of the incubation
>Cask Data will transfer the trademark to Apache Foundation.
>= External Dependencies =
>The dependencies all have Apache-compatible licenses:
> * dropwizard metrics (Apache 2.0)
> * fastutil (Apache 2.0)
> * gson (Apache 2.0)
> * guava-libraries (Apache 2.0)
> * guice (Apache 2.0)
> * hadoop (Apache 2.0)
> * hbase (Apache 2.0)
> * hdfs (Apache 2.0)
> * junit (EPL v1.0)
> * logback (EPL v1.0 )
> * slf4j (MIT)
> * thrift (Apache 2.0)
> * twill (Apache 2.0)
> * zookeeper (Apache 2.0)
>= Cryptography =
>Tephra does not use cryptography itself, however it can run on secure
>which uses Kerberos.
>= Required Resources =
>== Mailing Lists ==
> * tephra-private for private PMC discussions (with moderated
> * tephra-dev for technical discussions among contributors
> * tephra-commits for notification about commits
>== Subversion Directory ==
>Git is the preferred source control system: git://
>== Issue Tracking ==
>== Other Resources ==
>The existing code already has unit tests, so we would like a Hudson
>instance to run them whenever a new patch is submitted. This can be added
>after project creation.
>= Initial Committers =
> * Andreas Neumann <anew at apache dot org>
> * Terence Yim <chtyim at apache dot org>
> * Poorna Chandra <poorna at apache dot org>
> * Gokul Gunasekaran <gokul at cask dot co>
> * James Taylor <jamestaylor at apache dot org>
> * Thomas D'Silva <tdsilva at apache dot org>
> * Gary Helmling <garyh at apache dot org>
>= Affiliations =
> * Andreas Neumann (Cask Data)
> * Terence Yim (Cask Data)
> * Poorna Chandra (Cask Data)
> * Gokul Gunasekaran (Cask Data)
> * James Taylor (
> * Thomas D'Silva (
> * Gary Helmling (Facebook)
>= Sponsors =
>== Champion ==
>James Taylor <jamestaylor at apache dot org> (V.P., Apache Phoenix)
>== Nominated Mentors ==
> * James Taylor <jamestaylor at apache dot org>
> * Lars Hofhansl <larsh at apache dot org>
> * Andrew Purtell <apurtell at apache dot org>
> * Alan Gates <gates at apache dot org>
> * Henry Saputra <hsaputra at apache dot org>
>== Sponsoring Entity ==
>We are requesting that the Incubator sponsor this project.

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