Door List Matrices: How to Reconcile 2,000 Fest Attendees Across 4 Entrances in Realtime

The Problem of Distributed Festival Entrances

At a major university festival, attendees do not arrive through a single bottleneck. There are multiple entrance points: North Gate (Hostel residents and bus arrivals) South Gate (Day scholars and metro arrivals) VIP / Faculty Entrance (Judges, speakers, and college deans) Backstage Entry (Performing artists and band crews)

If Gate 1 admits a student on a paper checklist, Gate 2 has no way of knowing they are already inside.

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1. The Spark Realtime Door Matrix

In Spark (/dashboard/events/:id/checkin), organizers access the Live Door List Matrix:

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2. Realtime CDC Sync Across All Devices

Spark's architecture uses PostgreSQL Realtime Change Data Capture (CDC): When a scanner at North Gate admits an attendee, the database triggers a broadcast payload. The South Gate scanner and the central control room receive the update in under 150 milliseconds. * If the attendee attempts to hand their phone through the campus gate to an outside friend who runs to South Gate, South Gate’s scanner already knows the pass has been admitted.

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3. Rapid Search & Manual Name Resolution

If an attendee’s phone battery dies: Gate volunteers type the student’s name, college roll number, or phone number into the live search box. The system resolves the record instantly, confirms their identity, and allows the volunteer to execute a manual check-in with an audited reason.