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From keith-turner <>
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:
    --- Diff: core/src/main/java/org/apache/accumulo/core/client/ ---
    @@ -16,19 +16,20 @@
     package org.apache.accumulo.core.client;
     import java.util.Collection;
     import java.util.concurrent.TimeUnit;
      * 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.

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