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From: Fabien COELHO <coelho@cri.ensmp.fr>
To: PostgreSQL Developers <pgsql-hackers@postgresql.org>
Subject: pgbench - compute & show latency consistently
Date: Sat, 9 Jul 2016 10:42:27 +0200 (CEST)
Message-ID: <alpine.DEB.2.20.1607091035530.3412@sto> (raw)
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Currently the latency is not computed and displayed consistently:

  - the computation is wrong under -t (duration is zero...)

  - depending on the conditions it is shown with a ":" syntax or
    a "=" syntax.

The attached minor patch makes the computation & display more consistent.

-- 
Fabien.

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Attachments:

pgbench-latency-t-1.patch (text/x-diff, 1.7K) download
diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index f3afedb..26c030e 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -1254,8 +1254,8 @@ number of clients: 10
 number of threads: 1
 number of transactions per client: 1000
 number of transactions actually processed: 10000/10000
-latency average = 15.844 ms
-latency stddev = 2.715 ms
+latency average: 15.844 ms
+latency stddev: 2.715 ms
 tps = 618.764555 (including connections establishing)
 tps = 622.977698 (excluding connections establishing)
 script statistics:
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 87fb006..6eb9f28 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -3237,8 +3237,8 @@ printSimpleStats(char *prefix, SimpleStats *ss)
 	double		latency = ss->sum / ss->count;
 	double		stddev = sqrt(ss->sum2 / ss->count - latency * latency);
 
-	printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
-	printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
+	printf("%s average: %.3f ms\n", prefix, 0.001 * latency);
+	printf("%s stddev: %.3f ms\n", prefix, 0.001 * stddev);
 }
 
 /* print out results */
@@ -3291,9 +3291,9 @@ printResults(TState *threads, StatsData *total, instr_time total_time,
 	if (throttle_delay || progress || latency_limit)
 		printSimpleStats("latency", &total->latency);
 	else
-		/* only an average latency computed from the duration is available */
+		/* no measure, show average latency computed from run time */
 		printf("latency average: %.3f ms\n",
-			   1000.0 * duration * nclients / total->cnt);
+			   1000.0 * time_include * nclients / total->cnt);
 
 	if (throttle_delay)
 	{

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