[
https://issues.apache.org/jira/browse/ACCUMULO-3602?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14392035#comment-14392035
]
ASF GitHub Bot commented on ACCUMULO-3602:
------------------------------------------
Github user joshelser commented on a diff in the pull request:
https://github.com/apache/accumulo/pull/25#discussion_r27629663
--- Diff:
core/src/main/java/org/apache/accumulo/core/client/mapreduce/InputFormatBase.java
---
@@ -323,7 +382,7 @@ protected static TabletLocator
getTabletLocator(JobContext context) throws Table
* @since 1.6.0
*/
@Override
- protected void setupIterators(TaskAttemptContext context, Scanner
scanner, String tableName,
org.apache.accumulo.core.client.mapreduce.RangeInputSplit split) {
+ protected void setupIterators(TaskAttemptContext context, ScannerBase
scanner, String tableName,
org.apache.accumulo.core.client.mapreduce.AccumuloInputSplit split) {
--- End diff --
Sorry, we can't change these as they'd break API from 1.6.0. We can add to
the API for 1.7.0, but we can't remove. Need to deprecate the ones that take
Scanner and add in a new one for ScannerBase.
> BatchScanner optimization for AccumuloInputFormat
> -------------------------------------------------
>
> Key: ACCUMULO-3602
> URL: https://issues.apache.org/jira/browse/ACCUMULO-3602
> Project: Accumulo
> Issue Type: Improvement
> Components: client
> Affects Versions: 1.6.1, 1.6.2
> Reporter: Eugene Cheipesh
> Assignee: Eugene Cheipesh
> Labels: performance
> Fix For: 1.7.0
>
>
> Currently {{AccumuloInputFormat}} produces a split for reach {{Range}}
> specified in the configuration. Some table indexing schemes, for instance
> z-order geospacial index, produce large number of small ranges resulting in
> large number of splits. This is specifically a concern when using
> {{AccumuloInputFormat}} as a source for Spark RDD where each Split is mapped
> to an RDD partition.
> Large number of small RDD partitions leads to poor parallism on read and high
> overhead on processing. A desirable alternative is to group ranges by tablet
> into a single split and use {{BatchScanner}} to produce the records. Grouping
> by tablets is useful because it represents Accumulos attempt to distributed
> stored records and can be influance by the user through table splits.
> The grouping functionality already exists in the internal {{TabletLocator}}
> class.
> Current proposal is to modify {{AbstractInputFormat}} such that it generates
> either {{RangeInputSplit}} or {{MultiRangeInputSplit}} based on a new setting
> in {{InputConfigurator}}. {{AccumuloInputFormat}} would then be able to
> inspect the type of the split and instantiate an appropriate reader.
> The functinality of {{TabletLocator}} should be exposed as a public API in
> 1.7 as it is useful for optimizations.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
