| pg_test_fsync(1) - phpMan
PG_TEST_FSYNC(1) PostgreSQL 12.3 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 12.3 2020 PG_TEST_FSYNC(1)
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