pg_test_fsync
pg_test_fsync — determine fastestwal_sync_method forPostgreSQL
Synopsis
pg_test_fsync [option...]
Description
pg_test_fsync is intended to give you a reasonable idea of what the fastestwal_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 bypg_test_fsync might not make any significant difference in real database throughput, especially since many database servers are not speed-limited by their write-ahead logs.pg_test_fsync reports average file sync operation time in microseconds for eachwal_sync_method, which can also be used to inform efforts to optimize the value ofcommit_delay.
Options
pg_test_fsync accepts the following command-line options:
-f--filenameSpecifies the file name to write test data in. This file should be in the same file system that the
pg_waldirectory is or will be placed in. (pg_walcontains theWAL files.) The default ispg_test_fsync.outin the current directory.-s--secs-per-testSpecifies the number of seconds for each test. The more time per test, the greater the test's accuracy, but the longer it takes to run. The default is 5 seconds, which allows the program to complete in under 2 minutes.
-V--versionPrint thepg_test_fsync version and exit.
-?--helpShow help aboutpg_test_fsync command line arguments, and exit.
Environment
The environment variablePG_COLOR specifies whether to use color in diagnostic messages. Possible values arealways,auto andnever.