TRANSACTIONS AND LOCK MANAGEMENT

PostgreSQL's lock management and transactions are essential for maintaining data integrity, consistency, and concurrent access control.
The following explains how these ideas operate:
  • Atomicity: Guarantees that every action taken during a transaction is successful; if not, the entire transaction is reversed.
  • Consistency: Assures that a transaction will preserve database rules and constraints while moving the database from one legitimate state to another.
  • Isolation: Manages the visibility of transaction processes to other ongoing transactions. Several levels of isolation are supported by PostgreSQL.
  • Read Uncommitted: Data that may not yet be committed can be read by transactions. By default, a transaction only reads data that has been committed before to the start of the query.
  • Repeatable Read: Guarantees that the data will remain consistent even if a transaction reads the same row repeatedly.
  • Serializable: The maximum level of isolation, guaranteeing that transactions are carried out so that different transactions don't impact their outcomes.
  • Durability: Despite a system crash, changes made after a transaction is committed are irreversible.

    LOCK MANAGEMENT : When several transactions are accessing the same data at once, lock management is crucial for maintaining data integrity and avoiding problems like data corruption or deadlocks.

    (Table Level Locks, Row Level Locks)