Long-running transactions

From Postgres FM by Nikolay Samokhvalov and Michael Christofides

March 27, 2026 · 48 min · Episode 175

About this episode

Nik and Michael discuss long-running transactions, their implications, and mitigation strategies.

Nik and Michael discuss long-running transactions, including when they're harmless, when they cause issues, and how to mitigate those issues. Here are some links to things they mentioned: transaction_timeout https://www.postgresql.org/docs/current/runtime-config-client.html#GUC-TRANSACTION-TIMEOUT Our episode on transaction_timeout https://postgres.fm/episodes/transaction_timeout Our episode on slow queries (which was also our first ever episode!) https://postgres.fm/episodes/slow-queries-and-slow-transactions Our episode on locks https://postgres.fm/episodes/locks lock_timeout https://www.postgresql.org/docs/current/runtime-config-client.html#GUC-LOCK-TIMEOUT Transaction Isolation levels https://www.postgresql.org/docs/current/transaction-iso.html pg_current_xact_id_if_assigned() https://pgpedia.info/p/pg_current_xact_id_if_assigned.html Monitor xmin horizon to prevent XID/MultiXID wraparound and high bloat (how-to guide by Nik) https://postgres.ai/docs/postgres-howtos/performance-optimization/monitoring/how-to-monitor-xmin-horizon idle_replication_slot_timeout https://www.postgresql.org/docs/current/runtime-config-replication.html#GUC-IDLE-REPLICATION-SLOT-TIMEOUT PREPARE…

People in this episode

Hosts: Nikolay Samokhvalov, Michael Christofides

Topics covered

long-running transactions
transaction management
performance optimization
PostgreSQL configuration
transaction issues
mitigation strategies

Keywords

transaction_timeout
lock_timeout
transaction isolation levels
pg_current_xact_id_if_assigned
idle_replication_slot_timeout
log_autovacuum_min_duration
XID wraparound
multiXID wraparound
slow queries
subtransactions

Mentioned in this episode

Organizations: PostgreSQL, Postgres FM, Postgres.ai

Books & works: PostgreSQL Subtransactions Considered Harmful