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From "Mattmann, Chris A (3980)" <>
Subject Re: [DISCUSS] Impala incubator proposal
Date Tue, 17 Nov 2015 19:18:31 GMT
Awesome! Glad to see this coming to the ASF :-)

Chris Mattmann, Ph.D.
Chief Architect
Instrument Software and Science Data Systems Section (398)
NASA Jet Propulsion Laboratory Pasadena, CA 91109 USA
Office: 168-519, Mailstop: 168-527
Adjunct Associate Professor, Computer Science Department
University of Southern California, Los Angeles, CA 90089 USA

-----Original Message-----
From: Henry Robinson <>
Reply-To: "" <>
Date: Tuesday, November 17, 2015 at 1:49 PM
To: "" <>
Subject: [DISCUSS] Impala incubator proposal

>Hi all -
>We'd like to start a discussion regarding a proposal to submit Impala to
>the Apache Incubator.
>The proposal text is available on the Wiki here:
>and pasted below for convenience.
>I'm excited to make this proposal, and look forward to the community's
>= Abstract =
>Impala is a high-performance C++ and Java SQL query engine for data stored
>in Apache Hadoop-based clusters.
>= Proposal =
>We propose to contribute the Impala codebase and associated artifacts
>documentation, web-site content etc.) to the Apache Software Foundation
>with the intent of forming a productive, meritocratic and open community
>around Impala’s continued development, according to the ‘Apache Way’.
>Cloudera owns several trademarks regarding Impala, and proposes to
>ownership of those trademarks in full to the ASF.
>= Background =
>Engineers at Cloudera developed Impala and released it as an
>Apache-licensed open-source project in Fall 2012. Impala was written as a
>brand-new, modern C++ SQL engine targeted from the start for data stored
>Apache Hadoop clusters.
>Impala’s most important benefit to users is high-performance, making it
>extremely appropriate for common enterprise analytic and business
>intelligence workloads. This is achieved by a number of software
>techniques, including: native support for data stored in HDFS and related
>filesystems, just-in-time compilation and optimization of individual query
>plans, high-performance C++ codebase and massively-parallel distributed
>architecture. In benchmarks, Impala is routinely amongst the very highest
>performing SQL query engines.
>= Rationale =
>Despite the exciting innovation in the so-called ‘big-data’ space, SQL
>remains by far the most common interface for interacting with data in both
>traditional warehouses and modern ‘big-data’ clusters. There is clearly a
>need, as evidenced by the eager adoption of Impala and other SQL engines
>enterprise contexts, for a query engine that offers the familiar SQL
>interface, but that has been specifically designed to operate in massive,
>distributed clusters rather than in traditional, fixed-hardware,
>warehouse-specific deployments. Impala is one such query engine.
>We believe that the ASF is the right venue to foster an open-source
>community around Impala’s development. We expect that Impala will benefit
>from more productive collaboration with related Apache projects, and under
>the auspices of the ASF will attract talented contributors who will push
>Impala’s development forward at pace.
>We believe that the timing is right for Impala’s development to move
>wholesale to the ASF: Impala is well-established, has been Apache-licensed
>open-source for more than three years, and the core project is relatively
>stable. We are excited to see where an ASF-based community can take Impala
>from this strong starting point.
>= Initial Goals =
>Our initial goals are as follows:
>* Establish ASF-compatible engineering practices and workflows
>* Refactor and publish existing internal build scripts and test
>infrastructure, in order to make them usable by any community member.
>* Transfer source code, documentation and associated artifacts to the ASF.
>* Grow the user and developer communities
>= Current Status =
>Impala is developed as an Apache-licensed open-source project. The source
>code is available at, and developer
>documentation is at The majority
>of commits to the project have come from Cloudera-employed developers, but
>we have accepted some contributions from individuals from other
>All code reviews are done via a public instance of the Gerrit review tool
>at, and discussed on a public mailing
>list. All patches must be reviewed before they are accepted into the
>codebase, via a voting mechanism that is similar to that used on Apache
>projects such as Hadoop and HBase.
>Before a patch is committed, it must pass a suite of pre-commit tests.
>These tests are currently run on Cloudera’s internal infrastructure. One
>our initial goals will be to work with the ASF Infrastructure team to find
>a way to run these tests in an acceptable way on publicly accessible
>Issues are tracked in JIRA at,
>in a way that is extremely similar to existing practices at other ASF
>= Meritocracy =
>We understand the central importance of meritocracy to the Apache Way. We
>will work to establish a welcoming, fair and meritocratic community, in
>part by expanding the set of committers on the project. Although Impala’s
>committer list will initially be dominated by members of the Impala
>engineering team at Cloudera, we look forward to growing a rich user and
>developer community.
>= Community =
>Impala has a strong user community (see
>!forum/impala-user), and a
>growing developer community (see
>!forum/impala-dev). We
>to attract more developers to the project, and we believe that the ASF’s
>open and meritocratic philosophy will help us with this. We note the
>success of other, similar projects already part of the ASF.
>= Core Developers =
>Most - but not all - of Impala’s core developers are not currently
>affiliated with the ASF, and will require new ICLAs.
>= Alignment =
>Impala is related to several other Apache projects:
>* Data that is read by Impala is very often stored in Apache Hadoop
>clusters powered by the HDFS filesystem.
>* Impala can also read data stored in Apache HBase
>* Metadata for databases, tables and so on is read by Impala from Apache
>* The preferred data format for HDFS-based tables is Apache Parquet, and
>Apache Avro is also a supported data format.
>* Impala is closely integrated with Kudu, which is also being proposed to
>the Incubator.
>* Impala uses Apache Thrift as its RPC and serialization framework of
>= Known Risks =
>== Orphaned Products ==
>Impala is used by most of Cloudera’s customers, and Cloudera remains
>committed to developing and supporting the project. Cloudera has a strong
>track record in standing behind projects that were contributed to the ASF
>by its employees, including Apache Flume, Apache Sqoop, and others. Other
>companies both ship and support Impala, lending credence to the idea that
>Impala is not at risk of being suddenly orphaned.
>== Inexperience with Open Source ==
>Although all committers on the initial list have significant experience
>with at least one open-source project - namely Impala - fewer have much
>experience with ASF-based software projects as contributors and community
>members. However, with the guidance of our mentors, committers who do have
>ASF experience, and time to learn during Incubation, we are confident that
>the project can be run in accordance with Apache principles on an ongoing
>== Homogeneous Developers ==
>The initial committers are employees of Cloudera.
>The project has received some contributions from developers outside of
>Cloudera, from individuals belonging to organizations such as Intel and
>Google, from hobbyists and from students using Impala to advance their
>understanding of distributed databases. The project attracted an active
>user community as well. We hope to continue to encourage contributions
>these developers and community members and grow them into committers after
>they have had time to continue their contributions.
>== Reliance on Salaried Developers ==
>Many of Impala’s initial set of committers work full-time on Impala, and
>are paid to do so. However, as mentioned elsewhere, we anticipate growth
>the developer community which we hope will include hobbyists and academics
>who have an interested in distributed data systems.
>== An Excessive Fascination with the Apache Brand ==
>Although we hope that Impala benefits from the Apache Brand, any reflected
>goodwill to Cloudera as the contributing entity is not the goal of
>establishing Impala as an Apache project. We will work with the Incubator
>PMC and the PRC to ensure that the Apache Brand is respected.
>= Documentation =
>Impala: A Modern, Open-Source SQL Engine for Hadoop (
>Impala’s developer wiki (
>Impala’s auto-generated API documentation (
>= Initial Source =
>Impala’s initial source contribution will come from
>= External Dependencies =
>Impala depends upon a number of third-party libraries, which we list
>We intend to compile a LICENSE.txt file in the very short term (see
>* Google gflags (BSD)
>* Google glog (BSD)
>* Apache Thrift (Apache Software License v2.0)
>* Apache Commons (Apache Software License v2.0)
>* Apache Thrift (Apache Software License v2.0)
>* Apache Hadoop (Apache Software License v2.0)
>* Apache HBase (Apache Software License v2.0)
>* Apache Hive (Apache Software License v2.0)
>* Boost (Boost Software License)
>* OpenLdap (OpenLDAP Software License)
>* rapidjson (MIT)
>* Google RE2 (BSD-style)
>* lz4 (BSD)
>* snappy (BSD)
>* cyrus-sasl (CMU License)
>* Apache Avro (Apache Software License v2.0)
>* Cloudera squeasel (Apache Software License v2.0)
>* Apache htrace (Incubating) (Apache Software License v2.0)
>* Apache Sentry (Incubating) (Apache Software License v2.0)
>* Apache Shiro (Apache Software License v2.0)
>* Twitter Bootstrap (Apache Software License v2.0)
>* d3 (BSD)
>* LLVM (BSD-like)
>Build and test dependencies:
>* ant (Apache Software License v2.0)
>* maven (Apache Software License v2.0)
>* cmake (BSD)
>* clang (BSD)
>* Google gtest (Apache Software License v2.0)
>= Required Resources =
>We request that following resources be created for the project to use:
>== Mailing lists ==
>* (moderated subscriptions)
>== Git repository ==
>== JIRA instance ==
>== Other Resources ==
>We hope to continue using Gerrit for our code review and commit workflow.
>We are involved with discussions that the Kudu team at Cloudera have been
>having with Jake Farrell to start discussions on how Gerrit can fit into
>the ASF. We know that several other ASF projects or podlings are also
>interested in Gerrit.
>If the Infrastructure team does not have the bandwidth to support gerrit,
>we will continue to support our own instance of gerrit for Impala, and
>the necessary integrations such that commits are properly authenticated
>maintain sufficient provenance to uphold the ASF standards (e.g. via the
>solution adopted by the AsterixDB podling).
>= Initial Committers =
>* Tim Armstrong
>* Alex Behm
>* Taras Bobrovytsky
>* Casey Ching
>* Martin Grund
>* Daniel Hecht
>* Michael Ho
>* Matthew Jacobs
>* Ishaan Joshi
>* Marcel Kornacker
>* Sailesh Mukil
>* Henry Robinson
>* John Russell
>* Dimitris Tsirogiannis
>* Skye Wanderman-Milne
>* Juan Yu
>== Affiliations ==
>All: Cloudera Inc.
>= Sponsors =
>== Champion ==
>Tom White
>== Nominated Mentors ==
>Tom White
>Todd Lipcon
>Carl Steinbach
>= Sponsoring Entity =
>We ask that the Incubator PMC sponsor this proposal.

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