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From els...@apache.org
Subject svn commit: r1687661 - /accumulo/site/trunk/content/release_notes/1.5.3.mdtext
Date Thu, 25 Jun 2015 22:58:21 GMT
Author: elserj
Date: Thu Jun 25 22:58:20 2015
New Revision: 1687661

URL: http://svn.apache.org/r1687661
Log:
CMS commit to accumulo by elserj

Modified:
    accumulo/site/trunk/content/release_notes/1.5.3.mdtext

Modified: accumulo/site/trunk/content/release_notes/1.5.3.mdtext
URL: http://svn.apache.org/viewvc/accumulo/site/trunk/content/release_notes/1.5.3.mdtext?rev=1687661&r1=1687660&r2=1687661&view=diff
==============================================================================
--- accumulo/site/trunk/content/release_notes/1.5.3.mdtext (original)
+++ accumulo/site/trunk/content/release_notes/1.5.3.mdtext Thu Jun 25 22:58:20 2015
@@ -25,21 +25,66 @@ this is a "patch version". This means th
 changes which were made were done in a backwards-compatible manner. Code that
 runs against 1.5.2 is guaranteed to run against 1.5.3.
 
-# Major Changes #
+We'd like to thank all of the committers and contributors which had a part in
+making this release from code contributions to testing. Everyone's efforts are
+greatly appreciated.
 
+# Security Changes
 
+## SSLv3 disabled (POODLE)
 
-# Performance Improvements #
+Many Accumulo services were capable of enabling wire encryption using
+SSL connectors. 1.5.3 disables the problematic SSLv3 version which was
+susceptible to the man-in-the-middle attack.
 
 
+# Notable Bug Fixes
 
-# Other improvements #
+## SourceSwitchingIterator Deadlock
 
+An instance of SourceSwitchingIterator, the Accumulo iterator which transparently manages
+whether data for a tablet read from memory (the in-memory map) or disk (HDFS after a minor
+compaction), was found deadlocked in a production system.
 
+This deadlock prevented the scan and the minor compaction from ever successfully completing
+without restarting the tablet server. ACCUMULO-3745 fixes the inconsistent synchronization
+inside of the SourceSwitchingIterator to prevent this deadlock from happening in the future.
 
-# Notable Bug Fixes #
+The only mitigation of this bug was to restart the tablet server that is deadlocked.
 
+## Table flush blocked indefinitely
 
+While running the Accumulo RandomWalk distributed test, it was observed that all activity
in
+Accumulo had stopped and there was an offline Accumulo metadata table tablet. The system
first
+tried to flush a user tablet, but the metadata table was not online (likely due to the agitation
+process which stops and starts Accumulo processes during the test). After this call, a call
to
+load the metadata tablet was queued but could not complete until the previous flush call.
Thus,
+a deadlock occurred.
+
+This deadlock happened because the synchronous flush call could not complete before the load
+tablet call completed, but the load tablet call couldn't run because of connection caching
we
+perform in Accumulo's RPC layer to reduce the quantity of sockets we need to create to send
data.
+ACCUMULO-3597 prevents this deadlock by forcing the use of a non-cached connection for the
RPC
+message requesting a metadata tablet to be loaded.
+
+While this feature does result in additional network resources to be used, the concern is
minimal
+because the number of metadata tablets is typically very small with respect to the total
number of
+tablets in the system.
+
+The only mitigation of this bug was to restart the tablet server that is hung.
+
+## RPC Connections not cached
+
+It was observed that the underlying connection for invoking RPCs were not actually being
cached,
+despite it being requested that they should be cached. While this did not result in a noticed
+performance impact, it was deficiency. [ACCUMULO-3574] ensures that connections are cached
when
+it is requested that they are.
+
+## Deletes on Thrift Proxy API ignored
+
+A user noted that when trying to specify a delete using the Accumulo Thrift Proxy, the delete
+was treated as an update. [ACCUMULO-3474] fixes the Proxy server such that deletes are properly
+respected as specified by the client.
 
 # Testing #
 
@@ -67,15 +112,27 @@ Accumulo configuration from `120s` to `2
     <th>Tests</th>
   </tr>
   <tr>
-    <td>N/A</tdt>
-    <td>N/A</td>
-    <td>N/A</td>
-    <td>N/A</td>
-    <td>N/A</td>
-    <td>N/A</td>
+    <td>Gentoo</tdt>
+    <td>2.6.0</td>
+    <td>1</td>
+    <td>3.4.5</td>
+    <td>No</td>
+    <td>Unit and Integration Tests</td>
+  </tr>
+  <tr>
+    <td>Centos 6.5</tdt>
+    <td>2.7.1</td>
+    <td>6</td>
+    <td>3.4.5</td>
+    <td>No</td>
+    <td>Continuous Ingest and Verify</td>
   </tr>
 </table>
 
+[ACCUMULO-3474]: https://issues.apache.org/jira/browse/ACCUMULO-3474
+[ACCUMULO-3574]: https://issues.apache.org/jira/browse/ACCUMULO-3574
+[ACCUMULO-3597]: https://issues.apache.org/jira/browse/ACCUMULO-3597
+[ACCUMULO-3745]: https://issues.apache.org/jira/browse/ACCUMULO-3745
 [api]: https://github.com/apache/accumulo/blob/1.7.0/README.md#api
 [readme]: https://github.com/apache/accumulo/blob/1.5.3/README.md
 [semver]: http://semver.org



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