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Rule usage snapshots

Updated on April 5, 2022

Pega Platform maintains statistics about the number of rule executions since startup. During system shutdown, the system saves these statistics to the Pega Platform database for later review and analysis.

The system holds these statistics as property values in the Log-RuleUsage class, with additional detail in the Log-RuleUsage-Details class.

Note: Log-RuleUsage data, which covers only rule types that are converted to Java code by rules assembly, is different from Log-Usage data, which covers system and requestor performance.

How it works

Pega Platform maintains statistics during operation which are written to the Pega Platform database for later review and analysis during application server shutdown.

These statistics cover all requestors of every type, with cumulative statistics since startup. This can be helpful in identifying the most frequently and least frequently executed rules (for those rule types that are assembled using rules assembly).

By "rule," this topic means "a Java class created by rules assembly." One Pega Platform activity named Alpha-Mort-.Recalculate might produce multiple rules, one for each variation in:

  • Primary page class at the time of assembly (for subclasses of Alpha-Mort-.)
  • Ruleset and version
  • Node
  • Ruleset list of the requestor


The value of the pzInsKey key property of a Log-RuleUsage is concatenated from these other property values:

  • pxClassName – Always Log-RuleUsage
  • pxSystemNode – Node ID of the node from which the snapshot was captured
  • The full Java class name of the assembled rule, starting with a type.
  • pyLabel – The snapshot name, such as "shutdown"

The Java class name identifies the rule type. Three examples are:


Unlike most other concrete classes derived from the Log- base class, the pxCreateDateTime property is not part of the key of the Log-RuleUsage class.

Statistics in Log-RuleUsage

The following properties are of primary interest in each snapshot row. All statistics are since startup of a node or since installation, covering all requestors of all types.

pyLabelIdentifies the type of snapshot. The value "shutdown" is reserved.
pxClassNameFull Java class name for the rule-assembled rule.rules assembly
pxFamilyName Rule type concatenated with visible key, converted to lowercase characters and converting special characters to underscore characters. For example:
pxLastUseDate and time that the rule was last executed.
pxNumPeeksNumber of times the class loader checked to see whether this entry was loaded.
pxNumInvalidateNumber of times the cache content was invalidated (unloaded), such that the next request forces rules assembly.rules assembly
pxNumLoadsNumber of times this class was loaded.
pxNumReloadNumber of times this class was reloaded without forcing a rules assembly.
pxRuleCountNumber of dependences that this rule has.
pxCreateDateTimeFirst date and time this rule was captured by this snapshot.
pxUpdateDateTImeMost recent date and time this rule was captured by this snapshot.
pxSizeSize of the Java CLASS file in bytes.
pxSystemNodeNode ID (hash) on which this snapshot was captured.Node ID
pxUseCountNumber of times this rule was requested from the cache.

Cumulative statistics

No automatic processing purges rows of the pr4_log_usage table. If your system has been shut down more than once, statistics for pxNumInvalidate, pxRuleCount, pxUseCount, pxNumReload, pxNumPeeks, pxNumLoads are cumulative since installation. Statistics for pxUpdateDateTime, pxLastUse are from the most recent shutdown.

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