Repository: accumulo Updated Branches: refs/heads/asf-site b1bf6c22e -> 45d81dfc4 refs/heads/gh-pages a9b0fda04 -> 6538290f3
Minor updates to 1.7.2 release notes. Project: http://git-wip-us.apache.org/repos/asf/accumulo/repo Commit: http://git-wip-us.apache.org/repos/asf/accumulo/commit/6538290f Tree: http://git-wip-us.apache.org/repos/asf/accumulo/tree/6538290f Diff: http://git-wip-us.apache.org/repos/asf/accumulo/diff/6538290f Branch: refs/heads/gh-pages Commit: 6538290f370ab48ad59526c87b5733c60a31cafa Parents: a9b0fda Author: Josh Elser <els...@apache.org> Authored: Thu Jun 23 10:55:04 2016 -0400 Committer: Josh Elser <els...@apache.org> Committed: Thu Jun 23 10:55:04 2016 -0400 ---------------------------------------------------------------------- release_notes/1.7.2.md | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/accumulo/blob/6538290f/release_notes/1.7.2.md ---------------------------------------------------------------------- diff --git a/release_notes/1.7.2.md b/release_notes/1.7.2.md index 5ffce6f..eebdc70 100644 --- a/release_notes/1.7.2.md +++ b/release_notes/1.7.2.md @@ -31,6 +31,10 @@ There was a bug ([ACCUMULO-4148][ACCUMULO-4148]) where multiple put calls with i An improvement was introduced to allow a max age before WAL files would be automatically rolled. Without a max age, they could stay open for writing indefinitely, blocking the Hadoop DataNode decomissioning process. For more information, see [ACCUMULO-4004][ACCUMULO-4004]. +### Remove copy of cached RFile index blocks + +Accumulo maintains an cache for file blocks in-memory as a performance optimization. This can be done safely because Accumulo RFiles are immutable, thus their blocks are also immutable. There are two types of these blocks: index and data blocks. Index blocks refer to the b-tree style index inside of each Accumulo RFile, while data blocks contain the sorted Key-Value pairs. In previous versions, when Accumulo extracted an Index block from the in-memory cache, it would copy the data. [ACCUMULO-4164][ACCUMULO-4164] removes this unnecessary copy as the contents are immutable and can be passed by reference. Ensuring that the Index blocks are not copied when accessed from the cache is a big performance gain at the file-access level. + ### Minor performance improvements. Tablet servers would previously always hsync at the start of a minor compaction, causing delays in the write pipeline. These additional syncs were determined to provide no additional durability guarantees and have been removed. See [ACCUMULO-4112][ACCUMULO-4112] for additional detail. @@ -40,13 +44,13 @@ A performance issue was identified and corrected ([ACCUMULO-1755][ACCUMULO-1755] ## Other Notable Changes - * [ACCUMULO-4146][ACCUMULO-4146] Avoid copy of RFile Index Blocks when already in cache. - * [ACCUMULO-4335][ACCUMULO-4335] Error conditions that result in a Halt should ensure non-zero process exit code. - * [ACCUMULO-4334][ACCUMULO-4334] Ingest rates reported through JMX did not match rates reported by Monitor. - * [ACCUMULO-4314][ACCUMULO-4314] Use statistics to choose better keys for RFile index. * [ACCUMULO-3923][ACCUMULO-3923] bootstrap_hdfs.sh script would copy incorrect jars to hdfs. + * [ACCUMULO-4146][ACCUMULO-4146] Avoid copy of RFile Index Blocks when already in cache. * [ACCUMULO-4155][ACCUMULO-4155] No longer publish javadoc for non-public API to website. (Still available in javadoc jars in maven) * [ACCUMULO-4173][ACCUMULO-4173] Provide balancer to balance table within subset of hosts. + * [ACCUMULO-4314][ACCUMULO-4314] Use statistics to choose better keys for RFile index. + * [ACCUMULO-4334][ACCUMULO-4334] Ingest rates reported through JMX did not match rates reported by Monitor. + * [ACCUMULO-4335][ACCUMULO-4335] Error conditions that result in a Halt should ensure non-zero process exit code. ## Testing @@ -78,3 +82,4 @@ HDFS High-Availability instances, forcing NameNode failover. [ACCUMULO-4155]: https://issues.apache.org/jira/browse/ACCUMULO-4155 [ACCUMULO-4173]: https://issues.apache.org/jira/browse/ACCUMULO-4173 [ACCUMULO-4151]: https://issues.apache.org/jira/browse/ACCUMULO-4151 +[ACCUMULO-4164]: https://issues.apache.org/jira/browse/ACCUMULO-4164
