Event Discarder

As previously noted, it’s not feasible to hold whole history of events in active database due to its performance degradation.

A special DBEventDiscarder service helps removing old events while ensuring to keep events which are unread by reliable consumers.

DBEventDiscarder expects evt database interface to be pre-configured on passed CCM.

API

• start( ccm, options)

  • start processing

  • options:

    • poll_period_ms=600e3 - event polling interval
    • limit_at_once=1000 - maximum number of events allowed to be removed at once.
    • event_table - event table name
    • consumer_table - consumer table name

• stop()

  • stop processing

Async Events

• workerError - no expected error during execution.
• eventDiscard - count of events discarded in iteration.

Usage

const DBEventDiscarder = require( './DBEventDiscarder' );

// Initialize CCM & DB connection
const ccm = new AdvancedCCM();
DBAutoConfig( as, ccm, { evt: {} } );

// Initialize and start DB Event Discarder helper
const discarder = new DBEventDiscarder();
discarder.on( 'workerError', notExpectedHandler );

as.add( ( as ) => discarder.start( ccm, {} ) );