Isolation levels.
also: isolation level · read committed · repeatable read · serializable isolation · snapshot isolation · read uncommittedHow much concurrent transactions can see of each other: read uncommitted, read committed, repeatable read and serializable, weakest to strongest.
the two-minute refresher
- Read uncommitted allows dirty reads of data that may roll back.
- Read committed stops dirty reads but allows non-repeatable reads.
- Repeatable read keeps a row stable within a transaction; serializable behaves as if transactions ran one at a time.
- Stronger isolation costs throughput: pick the weakest level your invariants survive.