pg_test_fsync

pg_test_fsync

pg_test_fsync

1

Application

pg_test_fsync

determine fastest

wal_sync_method

for

PostgreSQL

pg_test_fsync

option

Description#

pg_test_fsync is intended to give you a reasonable idea of what the fastest ??? 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 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 each wal_sync_method, which can also be used to inform efforts to optimize the value of ???.

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_wal directory is or will be placed in. (pg_wal contains the WAL files.) The default is pg_test_fsync.out in the current directory.

-s; --secs-per-test
Specifies 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; --version
Print the pg_test_fsync version and exit.

-?; --help
Show help about pg_test_fsync command line arguments, and exit.

Environment#

The environment variable PG_COLOR specifies whether to use color in diagnostic messages. Possible values are always, auto and never.

See Also#