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From Daniel Dai <>
Subject [DISCUSS] [PROPOSAL] Omid for Apache Incubator
Date Thu, 17 Mar 2016 20:17:28 GMT

I would like to propose Omid as an Apache Incubator project:

I've posted posted the text of the proposal below:


= Omid Proposal =

=== Abstract ===

Omid is a flexible, reliable, high performant and scalable ACID
transactional framework that allows client applications to execute
transactions on top of MVCC key/value-based NoSQL datastores
(currently Apache HBase) providing Snapshot Isolation guarantees on
the accessed data.

=== Proposal ===

Omid is a flexible open-source transactional framework that provides
ACID transactions with Snapshot Isolation guarantees on top of NoSQL
datastores. In particular, the current codebase brings the concept of
transactions to the popular Apache HBase datastore. Omid offers great
performance, it is highly available, and scalable. Omid's current
version is able to scale to thousands of clients triggering concurrent
transactions on application data stored in HBase. Omid can scale
beyond 100K transactions per second on mid-range hardware while
incurring in a minimal impact on the speed of data access in the
datastore. We’re currently experimenting with a prototype version that
can improve the performance up to ~380K TPS.

Omid has been publicly available as an open-source project in Github
under Apache License Version 2.0 since 2011 [1]. During these years,
it has generated certain interest in the open source community,
especially since the public presentation of the first version in
Hadoop Summit 2013 [2]. Currently the Github project has 241 Stars and
93 forks. Yahoo Inc. submits this proposal to the Apache Software
Foundation with the aim to transfer the Omid project -including its
source code and documentation- to Apache in order to start the build
of a stable open source community around it.


[2] Omid presentation at Hadoop Summit 2013:

=== Background ===

An Omid prototype was first released as an open-source project back in
2011. Inspired by Google Percolator [1], it offered a lock-free
approach to transactions in NoSQL datastores (See [2]). However,
during these years, the design of Omid has evolved significantly.
Whilst the current open-sourced version maintains many aspects of the
original implementation, it is the result of a major redesign of the
first prototype released in 2011.

Omid has now a more decentralized design that does not sacrifice the
consistency and performance of the original version. The current
design also enables Omid to scale to thousands of clients executing
transactions concurrently on application data stored in HBase.
Internally, Omid still utilizes a lock-free approach to support
multiple concurrent clients. Its design also relies on a centralized
conflict detection component, the TSO, which now resolves in an
efficient manner writeset collisions among concurrent transactions
without having to piggyback commit information to the clients. Another
important benefit of Omid is that it doesn't require any modification
of the underlying key-value datastore, HBase in this case. Moreover,
the recently added high availability algorithm allows to eliminate the
single point of failure represented by the TSO in those system
deployments requiring a higher degree of dependability. Last but not
least, the provided user API is very simple, mimicking transaction
managers in the relational world: begin, commit, rollback.

Omid is used internally at Yahoo. Sieve, Yahoo’s web-scale content
management platform powering some of next-generation search and
personalization products is using Omid as a transaction manager in its
processing pipeline. Sieve essentially acts as a huge processing hub
between content feeds and serving systems. It provides an environment
for highly customizable, real-time, streamed information processing,
with typical discovery-to-service latencies of just a few seconds. In
terms of scale and availability, Omid’s new design was largely driven
by Sieve’s requirements.

At Yahoo, we are also making an effort to disseminate the current
status of the project through blog entries (See [3], [4] and [5]) and
submissions to technical and academic conferences such as ATC 2016,
Hadoop Summit 2016, HBaseConf 2016. Last but not least, Omid also
appeared in a TechCrunch article in the last quarter of 2015 (See [6])

[1] D. Peng and F. Dabek, Large-scale Incremental Processing Using
Distributed Transactions and Notifications. USENIX Symposium on
Operating Systems Design and Implementation, 2010

[2] D. Gomez-Ferro, F. Junqueira, I. Kelly, B. Reed, and M. Yabandeh.
Omid: Lock-free transactional support for distributed data stores. In
Proc. of ICDE, 2013.





=== Rationale ===

Programming with ACID (Atomicity, Consistency, Isolation, Durability)
transactions is very popular and it is featured in relational
databases. However, in the Big Data ecosystem, applications typically
use NoSQL datastores, which do not provide ACID transactions. Such
NoSQL datastores used to give up transactional support for greater
agility and scalability. However, while early NoSQL data store
implementations did not include transaction support, the need for
transactions soon emerged in Big Data applications when accessing
shared data; for  example, transactions are very important  for
modern, scalable systems that process content incrementally.

NoSQL datastores -including HBase- don’t provide transactional
frameworks to coordinate the access to the underlying data for
preserving consistency. By using Omid, Big Data applications that need
to bundle multiple read and write operations on HBase into logically
indivisible units of work can execute transactions with ACID
properties, just as they would use transactions in the relational
database world. Omid extends the HBase key-value access APl with
transaction semantics. It can be exercised either directly, or via
higher level data management API’s. For example, Apache Phoenix
(SQL-on-top-of-HBase) might use Omid as its transaction management

The following features make Omid an attractive choice for system
designers and other projects in the Apache community:

* Semantics. Omid implements Snapshot Isolation (SI,) supported by
major SQL and NoSQL technologies (e.g. Google Percolator).

* Performance and Scalability. Omid  provides a highly scalable,
lock-free implementation of SI. To the best of our knowledge, it is
also one of the few open source NoSQL transactional platforms that can
execute more than 100K transactions per second [1]. A new prototype
still in development can go even further, up to ~380K TPS.

* Reliability.  Omid has a high-availability (HA) mode, in which the
core service performing writeset conflict resolution operates as
primary-backup process pair with automatic failover. The HA support
has zero overhead on the mainstream operation.

* Adaptability. Omid current version provides transactions on data
stored in Apache HBase. However, Omid’s components are generic enough
to be adapted to any other key-value NoSQL datasource that supports

* Development. Omid provides a very simple interface that mimics
standard HBase APIs, making it developer friendly. Only minimal
extensions to the standard interfaces have been introduced to enable

* Simplicity. Omid leverages the HBase infrastructure for managing its
own metadata. It entails no additional services apart from those
provided and used by HBase.

* Track Record. As we have mentioned, Omid is already in use by
very-large-scale production systems at Yahoo. Also, Hortonworks is
integrating Omid in a metastore implementation for Hive based on

[1] See also Haeinsa:

=== Current Status ===
Current Omid implementation is available in both, Yahoo’s internal
Github repository for internal use at Yahoo as well as in Yahoo’s
Github public repository ( Both
repositories are managed by Omid’s current developers at Yahoo.

As it is mentioned above, Yahoo is currently using Omid for providing
transactions in Sieve, a web-scale content management platform that
powers Yahoo’s next-generation search and personalization products.

==== Meritocracy ====
The first version of Omid was originally created in 2011 by Maysam
Yabandeh, Daniel Gomez-Ferro, Ivan B. Kelly, Benjamin Reed and Flavio
Junqueira at the R&D Scalable Computing Group of Yahoo Labs in Spain.

During the years after its inception, Omid has matured to operate at
Web scale and has been used internally by strategic projects at Yahoo
such as Sieve. The current base of committers belong to the Yahoo team
that took over the initial Omid prototype and rewrote it to meet the
high availability and scalability requirements of the Sieve project.
This base of committers has recently incorporated Hortonworks members
that helped in the Omid adaptation to HBase 1.x versions.

With this initial committer base, we aim to form a larger community
that can collaborate with new ideas over the current code base. This
new community will run the project following the "Apache Way"
( Users and new contributors
will be treated with respect and welcomed. To grow the community, we
will encourage contributors to provide patches, review code, propose
new features improvements, talk at conferences such as Hadoop Summit,
HBaseCon, ApacheCon, etc. Committership and PMC membership will be
offered according to meritocracy.

==== Community ====

The public Yahoo Omid repository at Github currently has 241 Stars and
93 forks, which means that there is an important interest for the
project in the open-source community, at least compared with other
similar projects (See

Recently, Hortonworks contributors to the Apache Hive project which
are working on storing Hive metadata in HBase (Apache Jira HIVE-9452)
manifested interest in using Omid. We started with them a fruitful
collaboration that resulted in Omid supporting HBase 1.x versions.

Salesforce is also interested in collaborating in doing a Proof of
Concept for integrating Omid as a pluggable transaction manager in
Apache Phoenix.

Yahoo, Hortonworks and Salesforce participants will constitute the
initial set of committers and mentors for the proposal.

==== Core Developers ====
The core developers of Omid are all skilled software developers and
research engineers at Yahoo Inc. and Hortonworks with years of
experiences in their fields. At this moment, developers are
distributed across U.S. and Israel. The aim is to incorporate more
committers from different organizations and locations over time.

The current set of developers include experienced committers from
Apache HBase, Hive and Hadoop projects that have been working with us
in the current codebase found in Github.

Finally, some of the core developers are currently NOT affiliated with
the ASF and would require new ICLAs to be filed.

=== Alignment ===
Omid enhances with transactions the already successful Apache HBase
datastore project. We have collaborated with other developers inside
and outside Yahoo which are involved in the Apache HBase community, so
we have had reliable feedback from them.

Although Omid brings value into HBase, the design of the current
version provides a general transaction scheme that can potentially be
adapted to other MVCC key-value datastores such as Apache Cassandra.

Apache Phoenix is also a potential target. Phoenix is a SQL layer on
top of HBase that can potentially integrate Omid in order to provide
the well-know concept of transactions to Phoenix-based applications.

=== Known Risks ===
==== Orphaned products ====
Yahoo’s Research and Search organizations have been taking care of
Omid development since the first prototype creation in 2011. Yahoo has
a long history participating in open-source projects, and has been
also a long time contributor to the Apache community. For example, in
Apache, Yahoo is an important contributor in many projects in the
Hadoop ecosystem such as HBase, Pig, Storm or YARN, and has also
open-sourced other well-known projects outside Hadoop, such as
Zookeeper or Bookkeeper. So it is in the best interest of Yahoo make
Omid also a successful open-source Apache product. If this happens, we
are sure that a larger community will be formed around the project in
a relatively short period of time, contributing to the diversification
and stabilization of the base of committers.

==== Inexperience with Open Source ====
This project has long standing experienced mentors and interested
contributors from Apache HBase, Hive and Phoenix to help us moving
through the open source process. We are actively working with
experienced Apache community members to improve our project and
further testing.

==== Homogeneous Developers ====
Omid has been supported by Yahoo since its inception in 2011. However,
all current committers are employed by their respective companies
shown in the Affiliations section.

==== Reliance on Salaried Developers ====

All the current developers are paid by their employers to contribute
to this project. Yahoo developers will also continuing maintaining the
internal Omid repository at their company.

Of course, other developers are welcomed to contribute to this project
after it is open sourced in Apache.

==== Relationships with Other Apache Product ====

Current Omid incarnation serves transactional contexts to applications
storing their data in HBase. However Omid design potentially allows to
be adapted to serve transactions on top of other MVCC-based key-value
datastores in Apache community such as Cassandra.

As a transactional framework, many other Apache projects such as
Apache Spark, Apache Phoenix, Apache Storm, Apache Flink could
potentially benefit from Omid to get transactional contexts. In
particular, Apache Phoenix -a SQL layer on top of HBase- might use
Omid as its transaction management component. Once we open source Omid
as an Apache project, we expect to generate more interest in the
surrounded communities.

Very recently, a new incubator proposal for a similar project called
Tephra, has been submitted to the ASF. We think this is good for the
Apache community, and we believe that there’s room for both proposals
as the design of each of them is based on different principles (e.g.
Omid does not require to maintain the state of ongoing transactions on
the server-side component) and due to the fact that both -Tephra and
Omid- have also gained certain traction in the open-source community.

With regard to the Apache projects that Omid uses, apart from HBase,
Omid relies on Apache Zookeeper and Curator projects in order to
coordinate the (re)connection of transaction managers (acting as
clients) to the conflict resolution component for transactions (server
side.) They’re also used in order to coordinate the master and backup
replicas in high availability scenarios.

==== An Excessive Fascination with the Apache Brand ====

We are applying to the Incubator process because we think that it is
the logical next step for the  Omid project after we open-sourced the
code in Github some years ago. Yahoo has a long-standing history of
contributing to Apache projects. The developers and contributors
understand the implications of making it an Apache project, and
strongly believe that the growing community can benefit from the
Apache environment, ecosystem, and infrastrastructure.

=== Documentation ===
Current documentation about the project is available in the wiki of
Omid’s Github repository: . It will
be moved under if the project
is accepted as an Apache Incubator.

=== Initial Source ===
Initial source code is currently hosted in Github for general viewing
and contribution:

Omid source code is written in Java code (99%) mixed with some shell
script (1%) in order to configure and trigger the execution of main

The code will be moved to Apache if accepted as
an Incubator project.

=== Source and Intellectual Property Submission Plan ===

The current Omid License for the code published in Github is Apache
2.0. If Omid fulfills and passes the conditions for being an Incubator
project in the ASF, the source code will be transitioned via the
Software Grant Agreement onto the ASF infrastructure and in turn made
available under the Apache License, version 2.0.

=== External Dependencies ===

The required external dependencies that are not Apache projects are
all Apache licenses or other compatible Licenses:

Maven & Maven plugins ( [Apache 2.0]

JDK7 or OpenJDK 7 ( [Oracle or Openjdk JDK License]

Google Guava v11.0.2 ( [Apache 2.0]

Google Guice v3.0 ( [Apache 2.0]

Testng v6.8.8  ( [Apache 2.0]

SLF4J ( v1.7.7 [MIT License]

Netty ( v3.2.6.Final [Apache 2.0]

Google Protocol Buffers v2.5.0
( [BSD License]

Mockito ( v1.9.5 [MIT License]

LMAX Disruptor v3.2.0 ( [Apache 2.0]

Coda Hale/ Dropwizard Metrics v3.0.1
( [Apache 2.0]

C.Beust, JCommander v1.35 ( [Apache 2.0]

Hamcrest v1.3 ( [BSD License]

=== Cryptography ===
Omid project does not use cryptography itself. However, Apache HBase
-the datastore on top of which Omid works in its current version- uses
standard APIs and tools for SSH and SSL communication where necessary.

=== Required Resources ===
We request that following resources be created for the project to use:

==== Mailing lists ====

omid-private (moderated subscriptions)

omid-commits (commit notification)
omid-dev (technical discussions)

==== Git repository ====

==== Documentation ====

==== JIRA instance ====

=== Initial Committers ===

* Daniel Dai, Hortonworks (daijy<AT>hortonworks<DOT>com)

* Alan Gates, Hortonworks, (gates<AT>hortonworks<DOT>com)

* Lars Hofhansl, Salesforce (larsh<AT>apache<DOT>org)

* Flavio P. Junqueira, Confluent (fpj<AT>apache<DOT>org)

* Igor Katkov (katkovi<AT>yahoo-inc<DOT>com)

* Francis C. Liu (fcliu<AT>yahoo-inc<DOT>com)

* Thejas Nair, Hortonworks (thejas<AT>hortonworks<DOT>com)

* Francisco Perez-Sorrosal (fperez<AT>yahoo-inc<DOT>com)

* Sameer Paranjpye (sparanjpye<AT>yahoo<DOT>com)

* Ohad Shacham (ohads<AT>yahoo-inc<DOT>com)

* James Taylor, Salesforce (jamestaylor<AT>apache<DOT>org>)

=== Additional Interested Contributors ===
* Ivan Kelly (ivank<AT>apache<DOT>org)

* Maysam Yabandeh (myabandeh<AT>dropbox<DOT>com)

=== Affiliations ===

* Edward Bortnikov, Yahoo Inc.

* Daniel Dai, Hortonworks

* Flavio P. Junqueira, Confluent

* Igor Katkov, Yahoo Inc.

* Ivan Kelly, Midokura

* Francis C. Liu, Yahoo Inc.

* Sameer Paranjpye, Arimo

* Francisco Perez-Sorrosal, Yahoo Inc.

* Ohad Shacham, Yahoo Inc.

* Maysam Yabandeh, Dropbox Inc.

=== Sponsors ===

==== Champion ====

Daniel Dai, Hortonworks (daijy<AT>hortonworks<DOT>com)

==== Nominated Mentors ====

Alan Gates, Hortonworks, (gates<AT>hortonworks<DOT>com)

Lars Hofhansl, Salesforce (larsh<AT>apache<DOT>org)

Flavio P. Junqueira, Confluent (fpj<AT>apache<DOT>org)

Thejas Nair, Hortonworks (thejas<AT>hortonworks<DOT>com)

James Taylor, Salesforce (jamestaylor<AT>apache<DOT>org>)

==== Sponsoring Entity ====
Apache Incubator PMC

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