lt_test_fsync — determine fastest wal_sync_method
for LightDB
lt_test_fsync
[option
...]
lt_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
lt_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.
lt_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.
lt_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
lt_wal
directory is or will be placed in.
(lt_wal
contains the WAL files.)
The default is lt_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 lt_test_fsync version and exit.
-?
--help
Show help about lt_test_fsync command line arguments, and exit.
The environment variable LT_COLOR
specifies whether to use
color in diagnostic messages. Possible values are
always
, auto
and
never
.