postgresql/src/test/isolation

src/test/isolation/README

Isolation tests
===============

This directory contains a set of tests for the serializable isolation level.
Testing isolation requires running multiple overlapping transactions, so
which requires multiple concurrent connections, and can't therefore be
tested using the normal pg_regress program.

To represent a test with overlapping transactions, we use a test specification
file with a custom syntax, described in the next section.

isolationtester is program that uses libpq to open multiple connections,
and executes a test specified by a spec file. A libpq connection string
to specify the server and database to connect to, the defaults derived from
environment variables are used otherwise.

pg_isolation_regress is a tool identical to pg_regress, but instead of using
psql to execute a test, it uses isolationtester.

To run the tests, you need to have a server up and running. Run
    gmake installcheck

Test specification
==================

Each isolation test is defined by a specification file, stored in the specs
subdirectory. A test specification consists of four parts, in this order:

setup { <SQL> }

  The given SQL block is executed once, in one session only, before running
  the test. Create any test tables or such objects here. This part is
  optional.

teardown { <SQL> }

  The teardown SQL block is executed once after the test is finished. Use
  this to clean up, e.g dropping any test tables. This part is optional.

session "<name>"

  Each session is executed in a separate connection. A session consists
  of four parts: setup, teardown and one or more steps. The per-session
  setup and teardown parts have the same syntax as the per-test setup and
  teardown described above, but they are executed in every session,
  before and after each permutation. The setup part typically contains a
  "BEGIN" command to begin a transaction.

  Each step has a syntax of

  step "<name>" { <SQL> }

  where <name> is a unique name identifying this step, and SQL is a SQL
  statement (or statements, separated by semicolons) that is executed in the
  step.

permutation "<step name>" ...

  A permutation line specifies a list of steps that are ran in that order.
  If no permutation lines are given, the test program automatically generates
  all possible overlapping orderings of the given sessions.

Lines beginning with a # are considered comments.