Name
pg_test_fsync -- determine fastestwal_sync_method
for PostgreSQL Synopsis
pg_test_fsync [option...]
Description
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 significant difference in real database throughput, especially since many database servers are not speed-limited by their transaction 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 commit_delay.
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 ispg_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.
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