Merge branch 'master' into initial-es5

* master:
  [core] Fixing squid:S1319 -  Declarations should use Java collection interfaces such as "List" rather than specific implementation classes such as "LinkedList". (manolama - updated bindings added since the PR)
  [core] Use longs instead of ints to support larger key spaces. Changed int to long in Measurements code to support large scale workloads. (manolama - fixed checkstyle errors)
  [core] Export totalHistogram for HdrHistogram measurement
  [core] Add an operation enum to the Workload class. This can eventually be used to replace the strings.
  [core] Add a Fisher-Yates array shuffle to the Utils class.
  [core] Fix an issue where the threadid and threadCount were not passed to the workload client threads. Had to use setters to get around the checkstyle complaint of having too many parameters.
  Upgrading googlebigtable to the latest version. The API used by googlebigtable has had quite a bit of churn.  This is the minimal set of changes required for the upgrade.
  [geode] Update to apache-geode 1.2.0 release
  [core] Update to use newer version of Google Cloud Spanner client and associated required change
  [core] Add a reset() method to the ByteIterator abstract and implementations for each of the children. This lets us re-use byte iterators if we need to access the values again (when applicable).
  [hbase12] Add HBase 1.2+ specific client that relies on the shaded client artifact provided by those versions. (brianfrankcooper#970)
  [distro] Refresh Apache licence text (brianfrankcooper#969)
  [memcached] support binary protocol (brianfrankcooper#965)
  [accumulo] A general "refresh" to the Accumulo binding (brianfrankcooper#947)
  [cloudspanner] Add binding for Google's Cloud Spanner. (brianfrankcooper#939)
  [aerospike] Change the write policy to REPLACE_ONLY (brianfrankcooper#937)

accumulo/README.md

@@ -36,7 +36,42 @@ Git clone YCSB and compile:
     cd YCSB
     mvn -pl com.yahoo.ycsb:aerospike-binding -am clean package
 
-### 3. Load Data and Run Tests
+### 3. Create the Accumulo table
+
+By default, YCSB uses a table with the name "usertable". Users must create this table before loading
+data into Accumulo. For maximum Accumulo performance, the Accumulo table must be pre-split. A simple
+Ruby script, based on the HBase README, can generate adequate split-point. 10's of Tablets per
+TabletServer is a good starting point. Unless otherwise specified, the following commands should run
+on any version of Accumulo.
+
+    $ echo 'num_splits = 20; puts (1..num_splits).map {|i| "user#{1000+i*(9999-1000)/num_splits}"}' | ruby > /tmp/splits.txt
+    $ accumulo shell -u <user> -p <password> -e "createtable usertable"
+    $ accumulo shell -u <user> -p <password> -e "addsplits -t usertable -sf /tmp/splits.txt"
+    $ accumulo shell -u <user> -p <password> -e "config -t usertable -s table.cache.block.enable=true"
+
+Additionally, there are some other configuration properties which can increase performance. These
+can be set on the Accumulo table via the shell after it is created. Setting the table durability
+to `flush` relaxes the constraints on data durability during hard power-outages (avoids calls
+to fsync). Accumulo defaults table compression to `gzip` which is not particularly fast; `snappy`
+is a faster and similarly-efficient option. The mutation queue property controls how many writes
+that Accumulo will buffer in memory before performing a flush; this property should be set relative
+to the amount of JVM heap the TabletServers are given.
+
+Please note that the `table.durability` and `tserver.total.mutation.queue.max` properties only
+exists for >=Accumulo-1.7. There are no concise replacements for these properties in earlier versions.
+
+    accumulo> config -s table.durability=flush
+    accumulo> config -s tserver.total.mutation.queue.max=256M
+    accumulo> config -t usertable -s table.file.compress.type=snappy
+
+On repeated data loads, the following commands may be helpful to re-set the state of the table quickly.
+
+    accumulo> createtable tmp --copy-splits usertable --copy-config usertable
+    accumulo> deletetable --force usertable
+    accumulo> renametable tmp usertable
+    accumulo> compact --wait -t accumulo.metadata
+
+### 4. Load Data and Run Tests
 
 Load the data: