Create a Deephaven configuration file

A Deephaven configuration file is a property file that sets the properties the Deephaven server reads at startup. This page shows how to create one, where the server looks for it, and how its settings combine with the defaults.

A configuration file sets Deephaven properties. It can't change Java Virtual Machine (JVM) arguments (such as -Xmx) or JVM system properties that the JVM reads at startup (such as java.io.tmpdir). To set those, see the production application script.

Create the file

To start from the default values in the built-in dh-defaults.prop file, add an includefiles line that names it. For the properties that file sets, see Configuration properties. The includefiles line must be the first non-comment line in the file:

If the file doesn't include dh-defaults.prop, the server doesn't load the values that file sets. Properties the server reads without a fallback in code must be set, either in your file or with a -D system property.

Save the file as deephaven.prop in <configDir>, the configuration directory. For where <configDir> is and how to change it, see Deephaven server bootstrap configuration.

Where the server looks for the file

The server uses the first of these that applies:

  1. The file named by the Configuration.rootFile system property. A system property is a Java property set on the command line with -D, so you set this one with -DConfiguration.rootFile=<path>. With the production start script, pass it in START_OPTS, for example START_OPTS="-DConfiguration.rootFile=<path>".
  2. The <configDir>/deephaven.prop file, if it exists.
  3. The built-in dh-defaults.prop file.

How settings combine

Properties later in the file override earlier ones, unless the earlier one is fixed with the final keyword, which the end of this section describes. The properties you add after includefiles override the defaults from dh-defaults.prop.

A system property set with -D on the command line overrides the same property in the configuration file. If that property is fixed with final (covered at the end of this section), the -D setting causes a configuration error instead.

You can mark a property final to fix its value. To do so, use one of these methods:

  • Prefix its line with final.
  • Put finalize <property name> on its own line.

For example, final PeriodicUpdateGraph.targetCycleDurationMillis=250 fixes the cycle time at 250 milliseconds. Any later line in the file that sets a final property, including another final line or a plain assignment, causes a configuration error.