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## Quick Start

This section describes how to run YCSB on [Accumulo](https://accumulo.apache.org/). 

### 1. Start Accumulo

See the [Accumulo Documentation](https://accumulo.apache.org/1.8/accumulo_user_manual.html#_installation)
for details on installing and running Accumulo.

Before running the YCSB test you must create the Accumulo table. Again see the 
[Accumulo Documentation](https://accumulo.apache.org/1.8/accumulo_user_manual.html#_basic_administration)
for details. The default table name is `ycsb`.

### 2. Set Up YCSB

Git clone YCSB and compile:

    git clone http://github.com/brianfrankcooper/YCSB.git
    cd YCSB
    mvn -pl com.yahoo.ycsb:accumulo1.8-binding -am clean package

### 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:

    ./bin/ycsb load accumulo1.8 -s -P workloads/workloada \
         -p accumulo.zooKeepers=localhost \
         -p accumulo.columnFamily=ycsb \
         -p accumulo.instanceName=ycsb \
         -p accumulo.username=user \
         -p accumulo.password=supersecret \
         > outputLoad.txt

Run the workload test:

    ./bin/ycsb run accumulo1.8 -s -P workloads/workloada  \
         -p accumulo.zooKeepers=localhost \
         -p accumulo.columnFamily=ycsb \
         -p accumulo.instanceName=ycsb \
         -p accumulo.username=user \
         -p accumulo.password=supersecret \
         > outputLoad.txt

## Accumulo Configuration Parameters

- `accumulo.zooKeepers`
  - The Accumulo cluster's [zookeeper servers](https://accumulo.apache.org/1.8/accumulo_user_manual.html#_connecting).
  - Should contain a comma separated list of of hostname or hostname:port values.
  - No default value.

- `accumulo.columnFamily`
  - The name of the column family to use to store the data within the table.
  - No default value.

- `accumulo.instanceName`
  - Name of the Accumulo [instance](https://accumulo.apache.org/1.8/accumulo_user_manual.html#_connecting).
  - No default value.

- `accumulo.username`
  - The username to use when connecting to Accumulo.
  - No default value.
 
- `accumulo.password`
  - The password for the user connecting to Accumulo.
  - No default value.