18th October 2018: PostgreSQL 11 Released!
Supported Versions: Current (11) / 10 / 9.6 / 9.5 / 9.4 / 9.3
Development Versions: devel
Unsupported versions: 9.2 / 9.1

F.34. pg_test_fsync

pg_test_fsync is intended to give you a reasonable idea of what the fastest wal_sync_method is on your specific system, as well as supplying diagnostic information in the event of an identified I/O problem. However, differences shown by pg_test_fsync might not make any difference in real database throughput, especially since many database servers are not speed-limited by their transaction logs.

F.34.1. Usage

pg_test_fsync [options]

pg_test_fsync accepts the following command-line options:

-f
--filename

Specifies the file name to write test data in. This file should be in the same file system that the pg_xlog directory is or will be placed in. (pg_xlog contains the WAL files.) The default is pg_test_fsync.out in the current directory.

-o
--ops-per-test

Specifies the number of operations per test. The more operations per test, the greater the test's accuracy, but the longer it takes to run. The default is 2000.