How One Team Used Postgres Advisory Locks to Safely Reset Monthly Usage Quotas

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A development team building a subscription-based app encountered quota reset failures for yearly subscribers and free-tier users, since both groups never trigger monthly payment events. To fix this, they built a Spring scheduler that runs at 00:05 UTC on the first of each month, decoupling quota resets from billing cycles entirely. The solution uses Postgres's pg_try_advisory_xact_lock to ensure only one application instance executes the reset job, even in multi-instance deployments. The non-blocking 'try' variant means competing instances exit immediately rather than queuing up, while the transaction-scoped lock auto-releases if the process crashes. The five-minute cron offset was deliberately chosen to avoid the load spike caused by multiple infrastructure jobs firing at exactly midnight.

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ProgrammingDEV Community ·

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