--- title: PostgreSQL Lockup vs Stale Connection: How to Tell Them... description: Two failure modes produce the same 'database is locked up' symptom in PostgreSQL: a true server lockup and a stale connection in the application pool. A true... canonical: https://daily.dev/posts/postgresql-lockup-vs-stale-connection-how-to-tell-them-apart-ctzk0b0lo twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: PostgreSQL Lockup vs Stale Connection: How to Tell Them Apart | daily.dev og:description: Two failure modes produce the same 'database is locked up' symptom in PostgreSQL: a true server lockup and a stale connection in the application pool. A true... og:url: https://daily.dev/posts/postgresql-lockup-vs-stale-connection-how-to-tell-them-apart-ctzk0b0lo og:image: https://api.daily.dev/og/posts/CTZK0B0lo.png og:image:alt: PostgreSQL Lockup vs Stale Connection: How to Tell Them Apart og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # PostgreSQL Lockup vs Stale Connection: How to Tell Them Apart **[Planet PostgreSQL](https://daily.dev/sources/planet-postgresql)** · 8 min read · 0 upvotes · 0 comments ## Summary Two failure modes produce the same 'database is locked up' symptom in PostgreSQL: a true server lockup and a stale connection in the application pool. A true lockup means no new connections can be established from anywhere, often caused by OS-level resource exhaustion. A stale connection means Postgres is healthy but a pooled connection died silently due to a load balancer, NAT gateway, or network interruption dropping the TCP session without notifying both sides. A five-step checklist helps distinguish them in under five minutes: try a fresh direct connection, check if only pre-existing pooled connections fail, look for 'reset by peer' errors in logs, and inspect pg_stat_activity. Fixes for stale connections involve configuring tcp_keepalives_idle/interval/count on the Postgres server, enabling keepaliveTime in HikariCP, tuning server_idle_timeout and client_idle_timeout in PgBouncer, and ensuring keepalive intervals are shorter than any middlebox idle timeout (e.g., AWS ALB defaults to 60s). PostgreSQL 14's client_connection_check_interval is also highlighted as an underused setting. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: --- Tags: [#database](https://daily.dev/tags/database), [#postgresql](https://daily.dev/tags/postgresql) [View this post on daily.dev](https://daily.dev/posts/postgresql-lockup-vs-stale-connection-how-to-tell-them-apart-ctzk0b0lo) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"PostgreSQL Lockup vs Stale Connection: How to Tell Them Apart","url":"https://daily.dev/posts/postgresql-lockup-vs-stale-connection-how-to-tell-them-apart-ctzk0b0lo","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/postgresql-lockup-vs-stale-connection-how-to-tell-them-apart-ctzk0b0lo"},"datePublished":"2026-08-03T15:48:21.746Z","dateModified":"2026-08-03T15:49:15.592Z","description":"Two failure modes produce the same 'database is locked up' symptom in PostgreSQL: a true server lockup and a stale connection in the application pool. 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