*As you know, we've split our post-2.1 release into two pieces, with 2.2 to
be released in July (rc1 out Monday
<http://cassandra.apache.org/download/>) and 3.0 in September.2.2 will
include Windows support, commitlog compression
<https://issues.apache.org/jira/browse/CASSANDRA-6809>, JSON support
<https://issues.apache.org/jira/browse/CASSANDRA-7970>, role-based
authorization
<http://www.datastax.com/dev/blog/role-based-access-control-in-cassandra>,
bootstrap-aware leveled compaction
<https://issues.apache.org/jira/browse/CASSANDRA-7460>, and user-defined
functions
<http://christopher-batey.blogspot.com/2015/05/cassandra-aggregates-min-max-avg-group.html>.
3.0 will include a major storage engine rewrite
<https://issues.apache.org/jira/browse/CASSANDRA-8099> and materialized
views <https://issues.apache.org/jira/browse/CASSANDRA-6477>.We're
splitting things up this way because we don't want to block the features
that are already complete while waiting for 8099 (the new storage engine).
Releasing them now as 2.2 reduces the risk for users (2.2 has a lot in
common with 2.1) and allows us to stabilize that independently of the
upheaval from 8099.After 3.0, we'll take this even further: we will release
3.x versions monthly. Even releases will include both bugfixes and new
features; odd releases will be bugfix-only. You may have heard this
referred to as "tick-tock" releases, after Intel's policy of changing
process and architecture independently
<http://www.intel.com/content/www/us/en/silicon-innovations/intel-tick-tock-model-general.html>.The
primary goal is to improve release quality. Our current major "dot zero"
releases require another five or six months to make them stable enough for
production. This is directly related to how we pile features in for 9 to
12 months and release all at once. The interactions between the new
features are complex and not always obvious. 2.1 was no exception, despite
DataStax hiring a full time test engineering team specifically for Apache
Cassandra.We need to try something different. Tick-tock releases will
dramatically reduce the number of features in each version, which will
necessarily improve our ability to quickly track down any regressions. And
"pausing" every other month to focus on bug fixes will help ensure that we
don't accumulate issues faster than we can fix them.Tick-tock will also
prevent situations like the one we are in now with 8099 delaying everything
else. Users will get to test new features almost immediately.To get there,
we are investing significant effort in making trunk "always releasable,"
with the goal that each release, or at least each odd-numbered bugfix
release, should be usable in production. We’ve extended our continuous
integration server to make it easy for contributors to run tests against
feature branches
<http://www.datastax.com/dev/blog/cassandra-testing-improvements-for-developer-convenience-and-confidence>
before merging to trunk and we’re working on more test infrastructure
<https://docs.google.com/document/d/1Seku0vPwChbnH3uYYxon0UO-b6LDtSqluZiH--sWWi0>
and procedures
<https://docs.google.com/document/d/1ptr47UQ56N80jqL_O6AlE67b0STyn_cVp2k5DTv-OMc>
to improve release quality. You can see how this is coming along in our
May retrospective
<https://docs.google.com/document/d/1GtuYRocdr9luNdwmm8wE84uC5Wr6TvewFbQtqoAFVeU/edit>.We
are also extending our backwards compatibility policy to cover all 3.x
releases: you will be able to upgrade seamlessly from 3.1 to 3.7, for
instance, including cross-version repair. We will not introduce any extra
upgrade requirements or remove deprecated features until 4.0, no sooner
than a year after 3.0.Under normal conditions, we will not release 3.x.y
stability releases for x > 0. That is, we will have a traditional 3.0.y
stability series, but the odd-numbered bugfix-only releases will fill that
role for the tick-tock series -- recognizing that occasionally we will need
to be flexible enough to release an emergency fix in the case of a critical
bug or security vulnerability.We do recognize that it will take some time
for tick-tock releases to deliver production-level stability, which is why
we will continue to deliver 2.2.y and 3.0.y bugfix releases. (But if we do
demonstrate that tick-tock can deliver the stability we want, there will be
no need for a 4.0.y bugfix series, only 4.x tick-tock.) After 2.2.0 is
released, 2.0 will reach end-of-life as planned. After 3.0.0 is released,
2.1 will also reach end of life. This is earlier than expected, but 2.2
will be very close to as stable as 2.1 and users will be well served by
upgrading. We will maintain the 2.2 stability series until 4.0 is
released, and 3.0 for six months after that.Thanks for reading this far,
and I look forward to hearing how 2.2rc1 works for you!*
--
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder, http://www.datastax.com
@spyced
