#defineLABEL_FORMAT" %-32s"

#defineNA_FORMAT"%18s"

#defineOPS_FORMAT"%9.3f ops/sec"

#defineOPS_FORMAT"%9.3f ops/sec (%6.f microsecs/op)"

#defineUSECS_SEC1000000

doubletotal_time= (stop_t.tv_sec-start_t.tv_sec)+

(stop_t.tv_usec-start_t.tv_usec)*0.000001;

doubleper_second=ops /total_time;

doubleavg_op_time_us= (total_time /ops)*USECS_SEC;

printf(OPS_FORMAT"\n",per_second);

printf(OPS_FORMAT"\n",per_second,avg_op_time_us);

}

<application>pg_test_fsync</> is intended to give you a reasonable

idea of what the fastest <xref linkend="guc-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 <application>pg_test_fsync</application>

might not make any difference in real database throughput, especially

since many database servers are not speed-limited by their transaction

logs.

as well as supplying diagnostic information in the event of an identified I/O

problem. However, differences shown by

<application>pg_test_fsync</application> might not make any significant

difference in real database throughput, especially since many database servers

are not speed-limited by their transaction logs.

<application>pg_test_fsync</application> reports average file sync operation

time in microseconds for each wal_sync_method, which can be used to inform

efforts to optimize the value of <varname>commit_delay</varname>.

</para>

</refsect1>