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From danburk...@apache.org
Subject incubator-kudu git commit: Add 4/11 weekly update
Date Mon, 11 Apr 2016 18:50:13 GMT
Repository: incubator-kudu
Updated Branches:
  refs/heads/gh-pages c78a2f80e -> 5519d13df

Add 4/11 weekly update

Change-Id: Ie8eccc133c16aee7a38d174065f000db518f419f
Reviewed-on: http://gerrit.cloudera.org:8080/2752
Reviewed-by: Todd Lipcon <todd@apache.org>
Tested-by: Todd Lipcon <todd@apache.org>

Project: http://git-wip-us.apache.org/repos/asf/incubator-kudu/repo
Commit: http://git-wip-us.apache.org/repos/asf/incubator-kudu/commit/5519d13d
Tree: http://git-wip-us.apache.org/repos/asf/incubator-kudu/tree/5519d13d
Diff: http://git-wip-us.apache.org/repos/asf/incubator-kudu/diff/5519d13d

Branch: refs/heads/gh-pages
Commit: 5519d13df6d04e745dcb8a002d9ca026ecaaa0de
Parents: c78a2f8
Author: Todd Lipcon <todd@cloudera.com>
Authored: Mon Apr 11 09:18:12 2016 -0700
Committer: Todd Lipcon <todd@apache.org>
Committed: Mon Apr 11 17:11:45 2016 +0000

 _posts/2016-04-11-weekly-update.md | 83 +++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)

diff --git a/_posts/2016-04-11-weekly-update.md b/_posts/2016-04-11-weekly-update.md
new file mode 100644
index 0000000..9c1693a
--- /dev/null
+++ b/_posts/2016-04-11-weekly-update.md
@@ -0,0 +1,83 @@
+layout: post
+title: Apache Kudu (incubating) Weekly Update April 11, 2016
+author: Todd Lipcon
+Welcome to the fourth edition of the Kudu Weekly Update. This weekly blog post
+covers ongoing development and news in the Apache Kudu (incubating) project.
+If you find this post useful, please let us know by emailing the
+[kudu-user mailing list](mailto:user@kudu.incubator.apache.org) or
+tweeting at [@ApacheKudu](https://twitter.com/ApacheKudu). Similarly, if you're
+aware of some Kudu news we missed, let us know so we can cover it in
+a future post.
+## Project news
+* The first release candidate for the 0.8.0 release was voted upon last week by
+  the Kudu project members as well as the Apache Incubator PMC. The vote passed
+  on the first try, so this release candidate will is now the official 0.8.0
+  release.
+  The [release notes](http://getkudu.io/releases/0.8.0/docs/release_notes.html)
+  summarize the new features, improvements, and important bug fixes. The
+  release itself and its documentation can be found at the
+  [Kudu 0.8.0 release](http://getkudu.io/releases/0.8.0/) page.
+  Thank you to the 11 developers who contributed the 172 bug fixes and
+  improvements for this release!
+* Congratulations to Binglin Chang who was elected as a new committer and
+  Podling Project Management Committee (PPMC) member this past week.
+  Binglin has contributed many bug reports and fixes and new features,
+  and has also given several presentations about Kudu. He is also the
+  first community member to run a Kudu cluster in a real production workload.
+  Thanks for your contributions, Binglin!
+## Development discussions and code in progress
+* Darren Hoo reported an issue on the mailing list where his Kudu daemons were
+  occasionally crashing in a workload involving large string cell values on the
+  order of tens of KB. Todd Lipcon investigated the issue and provided a [bug
+  fix](http://gerrit.cloudera.org:8080/2725).
+  It turns out that this bug has been present since the third week of Kudu
+  development in 2012. Given that the bug persisted so long, yet it was
+  relatively easy to reproduce, it highlights that Kudu needs further
+  testing for use cases with larger cell values. In particular, large
+  primary keys or updates containing large cells would trigger this problem.
+* Activity picked back up on the [design document for the Replay Cache feature](http://gerrit.cloudera.org:8080/#/c/2642/).
+  This feature's goal is to allow more transparent failovers between Kudu
+  servers and allow operations to be retried without affecting the semantics
+  seen by clients.
+  As an example, consider the case when an 'INSERT' operation of a single
+  row times out. Upon receiving a timeout response, the client does not know
+  whether the time out occurred before the insert was processed, or after.
+  The client may then retry the operation, perhaps on a different replica.
+  If the original operation was in fact successfully applied before the
+  timeout occurred, the client might receive an erroneous "row already exists"
+  error.
+  The "replay cache" feature, currently being designed by David Alves, is
+  meant to avoid this issue: each server will keep a relatively small cache
+  of recently applied operations so that, if a retry arrives, it can
+  correctly respond with the original result rather than applying it a second
+  time.
+* Binglin Chang reported an interesting bug where [two of three replicas were
+  online, but neither one was being elected as leader](https://issues.apache.org/jira/browse/KUDU-1391).
+  The issue occurred on his 70-node cluster after accidentally shutting down
+  about half of the servers for ten minutes. Upon recovery, one out of the
+  thousands of tablets got stuck in this situation. Mike Percy and Todd Lipcon
+  have been discussing the issue on the JIRA and seem to be converging on
+  some action items to prevent it from reoccurring.
+* Benjamin Kim revived an old thread about running [Spark on Kudu](http://markmail.org/thread/mznrulrh3o4625ei).
+  Users on the thread are piping up to write about their Spark use cases.
+  It seems likely that, given this interest, some Spark-on-Kudu improvements
+  will be happening in the near term. If you are interested in contributing,
+  please pipe up on the mailing list.

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