pg_test_fsync — determine fastest
wal_sync_method for PostgreSQL
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 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 commit_delay.
pg_test_fsync accepts the following command-line options:
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.
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.
Print the pg_test_fsync version and exit.
Show help about pg_test_fsync command line arguments, and exit.
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