Priming metrics

Prime metrics with existing values on process startup

Objective

Prime a metric family dataset with existing calculated data on process startup.

Joule will load an existing dataset from disk to memory as an initial image if this feature is enabled

Uses

Often business applications will start processing immediately rather than wait for a set period of time before systems settle, or in this case metrics created.

Hence, by priming the Joule process with a pre-calculated set of metrics processing can start immediately.

For configuration details read the Data priming at initialisation page

Example

This example loads a local parquet file to the target BidMovingAverage metric family table

stream:
  ...
  initialisation:
    data import:
      parquet:
        - schema: standardQuoteAnalyticsStream
          table: BidMovingAverage      
          files: ['data/parquet/mvavgs-prime.parquet']
          drop table: true
          index:
            fields: [ 'symbol' ]
            unique: false