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SQL Operations Guide

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SETENV DH_JVM_OPTION_STRINGS

Allows specifying specific options to the JVM.

JVM environments might require specific tuning parameters, for example, changing the default Garbage Collector (GC) or setting memory limits on JVM heap usage. Use this parameter to pass in those values to fine tune your specific JVM environment.

The example below limits JVM memory (this is the default specified in ctsrvr.cfg in V11 and later):

Example

SETENV DH_JVM_OPTIONS_STRINGS=-XX:+UseG1GC;-Xms100m;-Xmx300m

  • -Xms sets the initial heap size for JVM usage
  • -Xmx sets the maximum heap size for JVM usage
  • -XX:<jvm_parameter> sets specific optional Java JVM parameters. For example, setting desired garbage collectors for specific workloads.

For most server side processing such as stored procedures FairCom recommends the G1GC or newer garbage collector tuned to these types of multi-threaded server workloads, +XX:UseG1GC;

Consult the current Java documentation for your configured Java version and distribution for specific options available.

Default

None. When not provided the JVM is loaded with the Java defaults for that Java version, distribution and platform. Therefore it is advised to pass in your desired JVM parameters to ensure consistent usage parameters.

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