Chapter 13. Concurrency Control

   Table of Contents

   13.1. Introduction
   13.2. Transaction Isolation

        13.2.1. Read Committed Isolation Level
        13.2.2. Repeatable Read Isolation Level
        13.2.3. Serializable Isolation Level

   13.3. Explicit Locking

        13.3.1. Table-Level Locks
        13.3.2. Row-Level Locks
        13.3.3. Page-Level Locks
        13.3.4. Deadlocks
        13.3.5. Advisory Locks

   13.4. Data Consistency Checks at the Application Level

        13.4.1. Enforcing Consistency with Serializable Transactions
        13.4.2. Enforcing Consistency with Explicit Blocking Locks

   13.5. Serialization Failure Handling
   13.6. Caveats
   13.7. Locking and Indexes

   This chapter describes the behavior of the PostgreSQL database system
   when two or more sessions try to access the same data at the same time.
   The goals in that situation are to allow efficient access for all
   sessions while maintaining strict data integrity. Every developer of
   database applications should be familiar with the topics covered in
   this chapter.