These docs are for Cribl Stream 4.4 and are no longer actively maintained.
See the latest version (4.11).
Rollup Metrics
The Rollup Metrics Function merges/rolls up frequently generated incoming metrics into more manageable time windows.
Each Worker Process executes this Function independently on its share of events. For details, see Functions and Shared-Nothing Architecture.
Usage
Filter: Filter expression (JS) that selects data to feed through the Function. Defaults to true
, meaning it evaluates all events.
Description: Optional description of this Function’s purpose in this Pipeline. Defaults to empty.
Final: If toggled to Yes
, stops feeding data to the downstream Functions. Defaults to No
.
Dimensions: List of data dimensions across which to perform rollups. Supports wildcards. Defaults to *
wildcard, meaning all original dimensions.
Time window: The time span over which to roll up (aggregate) metrics. Must be a valid time string (e.g., 10s
). Must match pattern: \d+[sm]$
.
With high-cardinality data, beware of setting long time windows. Doing can cause high memory consumption and/or lost data, because memory is flushed upon restarts and redeployments.
Gauge update: The operation to use when rolling up gauge metrics. Defaults to Last; other options are Maximum, Minimum, or Average.
Examples
Scenario A:
Assume that you have metrics coming in at a rate that is too high. For example, Cribl Stream’s internal metrics come in at a 2s interval.
To roll up these metrics to 1-minute granularity, you would set up the Rollup Metrics Function with a Time Window value of 60s
.
Scenario B:
Assume that you have metrics coming up with multiple dimensions – e.g. host
, source
, data_center
, and application
. You want to aggregate these metrics to eliminate some dimensions.
Here, you would configure Rollup Metrics Function with a Time Window value that matches the metrics’ generation – e.g., 10s
. In the Dimensions field, you would remove the default *
wildcard, and would specify only the dimensions you want to keep – e.g.: host
, data_center
.