Postgres implicitly creates a transaction for any query modifying data outside of one. Transactions in MVCC are relatively cheap. The main resource of contenti

Postgres implicitly creates a transaction for any query modifying data outside of one. Transactions in MVCC are relatively cheap. The main resource of contention is a global txid that can disastrously wrap around if autovacuum is disabled. That process is responsible for a few other important tasks, like updating statistics for the query planner and maintaining BRIN indexes.