accumulo-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From keith-turner <...@git.apache.org>
Subject [GitHub] accumulo pull request: ACCUMULO-3959 More accurate BatchScanner ja...
Date Mon, 24 Aug 2015 18:55:39 GMT
Github user keith-turner commented on a diff in the pull request:

    https://github.com/apache/accumulo/pull/45#discussion_r37789259
  
    --- Diff: core/src/main/java/org/apache/accumulo/core/client/BatchScanner.java ---
    @@ -16,19 +16,20 @@
      */
     package org.apache.accumulo.core.client;
     
    +import org.apache.accumulo.core.data.Range;
    +
     import java.util.Collection;
     import java.util.concurrent.TimeUnit;
     
    -import org.apache.accumulo.core.data.Range;
    -
     /**
      * Implementations of BatchScanner support efficient lookups of many ranges in accumulo.
    + * BatchScanners are also appropriate for large, single ranges,
    + * as a BatchScanner will break those ranges up into separate RPCs
    + * provided the range spans more than one tablet
    + * and there are sufficiently many scan threads available.
    --- End diff --
    
    Maybe instead of suggesting how to use the batch scanner, we could focus more on describing
possible behavior?
    
      * May parallelize reading of data.  Multiple input ranges may be read in parallel or
sub ranges of individual input ranges may be read in parallel.
      * May return data in unsorted order.
      * May batch multiple ranges into a single RPC to a tserver.   
    
    Could still mention possible use cases like :
    
      * Looking up lots of small ranges
      * Parallelizing (spell check in web browser does not like that word) a computation over
an entire table using a large range w/ iterators.   This case may not return lots of data,
although lots of data may be read by the iterators.



---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.
---

Mime
View raw message