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.
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