Deep dive into the mismatch between Kotlin coroutine-based backends and traditional JDBC connection pools — how coroutine suspension semantics cause hidden pool exhaustion under load, why R2DBC's non-blocking model changes the calculus, and the specific dispatcher/pool sizing formulas and circuit-breaker patterns that prevent cascading failures during traffic spikes
title: "Fix Connection Pool Exhaustion: Kotlin Coroutines + HikariCP Under Load"
published: true
description: "Kotlin coroutines exhaust HikariCP pools because JDBC blocks threads coroutines can't reclaim. Here's the dispatcher sizing, R2DBC migration, and circuit-breaker setup that handles 10x spikes."
tags: kotlin, architecture, api, cloud
canonical_url: https://blog.mvp-factory.com/connection-pool-exhaustion-kotlin-coroutines-hikaricp
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