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PG_TEST_FSYNC(1) PostgreSQL 15.4 Documentation PG_TEST_FSYNC(1)
NAME
pg_test_fsync - determine fastest wal_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 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.
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
postgres(1)
PostgreSQL 15.4 2023 PG_TEST_FSYNC(1)