Configure Photon Running Environment

The Designer Cloud® application can connect to a high-performance environment embedded in the Alteryx node for execution of jobs against small- to medium-sized datasets, called the Trifacta Photon running environment.

• The  Trifacta Photon running environment can be selected in the Run Jobs page.

By default, the Trifacta Photon running environment is enabled for new installations.

Features:

• Faster execution times for transform and profiling jobs
• Better consistency with typecasting done in Spark jobs

This section provides information on how to enable and configure the Trifacta Photon running environment.

Limitations

Disable Trifacta Photon Running Environment

The Trifacta Photon running environment is enabled by default. Please complete the following configuration to disable the running environment.

Steps:

1. You can apply this change through the Admin Settings Page (recommended) or trifacta-conf.json. For more information, see Platform Configuration Methods.

2. To disable the Trifacta Photon running environment, apply the following configuration settings:

   "webapp.runInTrifactaServer": false,
   "feature.enableSamplingScanOptions": false,
   "feature.enableFirstRowsSample": false, 

3. Save your changes and restart the platform.

Example Configuration

The following configuration includes the default values.

"photon": {
  "cacheEnabled": true,
  "numThreads": 4,
  "enabled": true,
  "distroPath": "/photon/dist/centos6/photon",
  "traceExecution": false,
  "websocket": {
    "host": "localhost",
    "port": 8082
  },
  "mode": "wasm"
},

Some of these values apply to the Trifacta Photon client. For more information, see Configure Photon Client.

  "distroPath": "/photon/dist/centos6/photon",

Modify Limits

Runtime job timeout

By default, the Designer Cloud Powered by Trifacta platform imposes no limit on execution of a Trifacta Photon job. As needed, you can enable and configure a limit.

Steps:

1. You can apply this change through the Admin Settings Page (recommended) or trifacta-conf.json. For more information, see Platform Configuration Methods.

   "photon.timeoutEnabled": false,
   "photon.timeoutMinutes": 180,

   Setting	Description
   timeoutEnabled	Set to false to disable job limiting. Set to true to enable the timeout specified below.
   timeoutMinutes	Defines the number of minutes that a Trifacta Photon job is permitted to run. Default value is 180 (three hours).

2. Save your changes and restart the platform.

When a job has failed due to exceeding a timeout, additional information is available in the job logs. The following is a good search term for this type of error:

java.lang.Exception: Photon job '<jobId>' timeout

where <jobId> is the internal job identifier.

Job logs can be downloaded from the Job page. See Jobs Page.

Trifacta Photon running environment memory timeout

To prevent crashes, the Trifacta Photon running environment imposes a memory consumption limit for each job. If this memory timeout is exceeded, the job is automatically killed. As needed, you can disable this memory protection (not recommended) or change the memory threshold when jobs are killed.

Steps:

1. You can apply this change through the Admin Settings Page (recommended) or trifacta-conf.json. For more information, see Platform Configuration Methods.

2. Locate the following settings:

   "photon.memoryMonitorEnabled": false,
   "photon.memoryPercentageThresold": 60,

   Setting	Description
   memoryMonitorEnabled	Set to false to disable memory monitoring. Set to true to enable the threshold specified below.
   memoryPercentageThreshold	Defines the percentage of total available system memory that a Trifacta Photon job process is permitted to consume. Default value is 60 (60%). Tip: This threshold applies to individual jobs. If this threshold value is over 50%, it is possible for two concurrent Trifacta Photon jobs to use more than the available memory, crash the server, and force a restart. You may wish to start by setting threshold values at a lower level.

3. Save your changes and restart the platform.

When a job has failed due to exceeding this memory threshold, additional information is available in the job logs. The following is a good search term for this type of error:

java.lang.Exception: Photon job '<jobId>' failed with memory consumption over threshold

where <jobId> is the internal job identifier.

Below this line item, you may see the following entries, which can provide additional information to adjust the memory settings:

2017-05-04T02:26:40.549Z [job-id 740] com.trifacta.joblaunch.util.ProcessMonitorUtil [Thread-20] INFO  com.trifacta.joblaunch.util.ProcessMonitorUtil - Global memory size: 8373186560 bytes
2017-05-04T02:26:40.555Z [job-id 740] com.trifacta.joblaunch.util.ProcessMonitorUtil [Thread-20] INFO  com.trifacta.joblaunch.util.ProcessMonitorUtil - Available global memory size at process start: 2672959488 bytes
...
2017-05-04T02:29:15.690Z [job-id 740] com.trifacta.joblaunch.util.ProcessMonitorUtil [Thread-20] INFO  com.trifacta.joblaunch.util.ProcessMonitorUtil - Current memory consumption: 5.614080429077148%
2017-05-04T02:29:15.691Z [job-id 740] com.trifacta.joblaunch.util.ProcessMonitorUtil [Thread-20] ERROR com.trifacta.joblaunch.util.ProcessMonitorUtil - Average memory consumption for the past 15 seconds over 5% threshold: 5.174326801300049 %. Current available global memory: 2244628480 bytes

Current memory consumption

Job logs can be downloaded from the Job page. See Jobs Page.

Batch FileSystem Access Timeout Settings

The default timeout settings for reading and writing of data from the client browser through Trifacta Photon running environment to the Alteryx node should work in most cases.

Particularly when reading from large tables, you might discover errors similar to the following:

06:21:21.365 [Job 23] INFO com.trifacta.hadoopdata.photon.BatchPhotonRunner - terminating with uncaught exception of type Poco::TimeoutException: Timeout
06:21:21.375 [Job 23] INFO com.trifacta.hadoopdata.photon.BatchPhotonRunner - /vagrant/photon/dist/centos6/photon/bin/photon-cli: line 22: 15639 Aborted $
Unknown macro: {command[@]}

Steps:

1. You can apply this change through the Admin Settings Page (recommended) or trifacta-conf.json. For more information, see Platform Configuration Methods.

2. Locate the photon.extraCliArgs node.

3. Add the following values to the extraCliArgs entry:

   "photon.extraCliArgs" : "-batch_vfs_read_timeout <300> -batch_vfs_write_timeout <300>"

   Argument	Description
   -batch_vfs_read_timeout	Timeout limit in seconds of read operations from the datastore. Default value is 300 seconds (5 minutes). Tip: Raising the value to 3600 seconds should be fine in most environments. Avoid setting this value above 7200 seconds (2 hours).
   -batch_vfs_write_timeout	Timeout limit in seconds of write operations to the datastore. Default value is 300 seconds (5 minutes). NOTE: Do not modify unless specifically instructed by Alteryx Support.

4. To reduce timeouts, raise the above settings.
5. Save your changes and restart the platform.

Tuning Photon

For more information on tuning the performance of Photon, see Tune Application Performance.

Configure VFS Service

The Trifacta Photon running environment interacts with backend datastores through the VFS service.

For more information, see Configure VFS Service.

Use Trifacta Photon Running Environment

When executing a job, select the Photon option.