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DTSTAMP:20261020T151709Z
DTSTART:20261105T213000Z
DTEND:20261105T221500Z
SUMMARY:Beyond Watermarks: Custom Flink Operators for Feature-Trigger Synch
 ronization
LOCATION:Room 2002
DESCRIPTION:Csanád Bakos\n\nAt Vinted — Europe's largest second-hand mar
 ketplace — Trust & Safety scores millions of events per second to catch 
 malicious users and policy-violating content in seconds. Each trigger need
 s features to decide. If features lag\, decisions are made on stale data. 
 Watermarks align time within a Flink job — not across the feature and tr
 igger jobs that meet at a Feature Store. This talk is about closing that g
 ap with custom operators\, and — more importantly — the decisions made
  before writing one. We'll work through the characteristics that drive the
  design (velocity\, cardinality\, lateness\, latency budget\, missing-data
  policy\, delivery semantics) and the one question that dominates the rest
 : is this feature only for this trigger\, or reusable? That axis decides w
 hether alignment stays in-job or crosses a job boundary. From there\, two 
 production walkthroughs of in-job enrichment show how the framework picks 
 the operator — and what timing cases each must survive. Then the pivot: 
 once a feature is reusable\, a Feature Store lookup at trigger time become
 s a coin flip on freshness. We close that gap with a custom operator built
  on ingestion notifications\, and show why Flink's built-in joins don't fi
 t. We finish on the operational realities the design has to hold up agains
 t in production: backfills\, redeployments\, and designing for the worst c
 ase rather than the happy path — plus the monitoring that makes timeout 
 tuning and failure diagnosis possible. Takeaways: a checklist for deciding
  whether cross-job alignment is needed at all; the operator patterns and t
 iming analysis behind two in-job designs; a custom ingestion-notification 
 operator that goes beyond what watermarks and built-in joins offer; and th
 e operational habits that keep it correct.
URL:https://sf26.rmoff.net/s/beyond-watermarks-custom-flink-operators-for-f
 eature-trigger-38
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