Manage Metrics


Managing metrics is a key aspect to the performance of the Joule runtime. By applying the compaction policy this will reduce the memory footprint required of the JVM and therefore the number of GC cycles.

Runtime Policy

This section configures when to start and how frequently metrics are calculated. Below the metrics computation will start after 2 minutes on process startup and thereafter every 1 minute.


truncate on start: true
compaction policy:
  frequency: 8
  time unit: HOURS

Compaction Policy Attributes

AttributeDescriptionData TypeRequired


Frequency metrics are computed. Minimum 15 second computation cycles


Default: 1

startup delay

First compute cycle delay.


Default: 5

time unit

Time unit used to set the scheduled processing policy

Supported units: SECONDS, MINUTES, HOURS


Default: MINUTES

Metric Management Attributes

Each metric definition includes management attributes to control how the metric table is managed throughout the Joule process lifetime. Since Joule uses an in-memory database the size of table needs to be managed

AttributeDescriptionData TypeRequired

truncate on start

Truncate the mtric tables on startup


Default: true

compaction policy


Frequency table compactions will occur


Default: 1

time unit

Time unit used to set the scheduled companion policy

Supported units: MINUTES and HOURS


Default: HOURS

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