Worker Configuration¶

Worker Heap Memory Size¶

The environment variable TAJO_WORKER_HEAPSIZE in conf/tajo-env.sh allow Tajo Worker to use the specified heap memory size.

If you want to adjust heap memory size, set TAJO_WORKER_HEAPSIZE variable in conf/tajo-env.sh with a proper size as follows:

TAJO_WORKER_HEAPSIZE=8000

The default size is 1000 (1GB).

Temporary Data Directory¶

TajoWorker stores temporary data on local file system due to out-of-core algorithms. It is possible to specify one or more temporary data directories where temporary data will be stored.

tajo-site.xml

<property>
  <name>tajo.worker.tmpdir.locations</name>
  <value>/disk1/tmpdir,/disk2/tmpdir,/disk3/tmpdir</value>
</property>

Maximum number of parallel running tasks for each worker¶

In Tajo, the capacity of running tasks in parallel are determined by available resources and workload of running queries. In order to specify it, please see [Worker Resources] (#ResourceConfiguration) section.

Worker Resources¶

Each worker can execute multiple tasks simultaneously. In Tajo, users can specify the total size of memory and the number of disks for each worker. Available resources affect how many tasks are executed simultaneously.

In order to specify the resource capacity of each worker, you should add the following configs to tajo-site.xml :

<property>
  <name>tajo.worker.resource.tajo.worker.resource.cpu-cores</name>
  <value>24</value>
</property>

 <property>
  <name>tajo.worker.resource.memory-mb</name>
  <value>5120</value>
</property>

<property>
  <name>tajo.worker.resource.tajo.worker.resource.disks</name>
  <value>6.0</value>
</property>

<property>
  <name>tajo.worker.resource.dedicated</name>
  <value>true</value>
</property>