Batch Writing and Scanning Example

This tutorial uses the following Java classes, which can be found in org.apache.accumulo.examples.simple.client in the examples-simple module:

  • - writes mutations with sequential rows and random values
  • - used by SequentialBatchWriter to generate random values
  • - reads random rows and verifies their values

This is an example of how to use the batch writer and batch scanner. To compile the example, run maven and copy the produced jar into the accumulo lib dir. This is already done in the tar distribution.

Below are commands that add 10000 entries to accumulo and then do 100 random queries. The write command generates random 50 byte values.

Be sure to use the name of your instance (given as instance here) and the appropriate list of zookeeper nodes (given as zookeepers here).

Before you run this, you must ensure that the user you are running has the “exampleVis” authorization. (you can set this in the shell with “setauths -u username -s exampleVis”)

$ ./bin/accumulo shell -u root -e "setauths -u username -s exampleVis"

You must also create the table, batchtest1, ahead of time. (In the shell, use “createtable batchtest1”)

$ ./bin/accumulo shell -u username -e "createtable batchtest1"
$ ./bin/accumulo org.apache.accumulo.examples.simple.client.SequentialBatchWriter -i instance -z zookeepers -u username -p password -t batchtest1 --start 0 --num 10000 --size 50 --batchMemory 20M --batchLatency 500 --batchThreads 20 --vis exampleVis
$ ./bin/accumulo org.apache.accumulo.examples.simple.client.RandomBatchScanner -i instance -z zookeepers -u username -p password -t batchtest1 --num 100 --min 0 --max 10000 --size 50 --scanThreads 20 --auths exampleVis
07 11:33:11,103 [client.CountingVerifyingReceiver] INFO : Generating 100 random queries...
07 11:33:11,112 [client.CountingVerifyingReceiver] INFO : finished
07 11:33:11,260 [client.CountingVerifyingReceiver] INFO : 694.44 lookups/sec   0.14 secs

07 11:33:11,260 [client.CountingVerifyingReceiver] INFO : num results : 100

07 11:33:11,364 [client.CountingVerifyingReceiver] INFO : Generating 100 random queries...
07 11:33:11,370 [client.CountingVerifyingReceiver] INFO : finished
07 11:33:11,416 [client.CountingVerifyingReceiver] INFO : 2173.91 lookups/sec   0.05 secs

07 11:33:11,416 [client.CountingVerifyingReceiver] INFO : num results : 100