مستويات العزل في PostgreSQL

في هذا الدرس

know what each level prevents in PostgreSQL specifically.

الموضوعات المخطط لها

• READ COMMITTED (default): each statement sees committed data; allows non-repeatable reads, phantoms, lost updates, write skew.
• REPEATABLE READ: one snapshot per transaction (snapshot isolation); prevents dirty, non-repeatable, phantom reads; detects some lost updates by failing with a serialization error; still allows write skew.
• SERIALIZABLE: prevents all anomalies by detecting dangerous patterns and aborting one transaction.
• PostgreSQL never allows dirty reads; READ UNCOMMITTED behaves as READ COMMITTED.
• Higher levels mean you must retry on failure (SQLSTATE 40001).