New submission which put option help in alphabetical position, as
per Peter Eisentraut f0ed3a8a99b052d2d5e0b6153a8907b90c486636
This is for reference to the next commitfest.
--
Fabien.
diff --git a/contrib/pgbench/pgbench.c b/contrib/pgbench/pgbench.c
index 24dab1f..a86c862 100644
--- a/contrib/pgbench/pgbench.c
+++ b/contrib/pgbench/pgbench.c
@@ -137,6 +137,12 @@ int unlogged_tables = 0;
double sample_rate = 0.0;
/*
+ * whether clients are throttled to a given rate, expressed as a delay in us.
+ * 0, the default means no throttling.
+ */
+int64 throttle = 0;
+
+/*
* tablespace selection
*/
char *tablespace = NULL;
@@ -204,6 +210,8 @@ typedef struct
int nvariables;
instr_time txn_begin; /* used for measuring transaction latencies */
instr_time stmt_begin; /* used for measuring statement latencies */
+ int64 trigger; /* previous/next throttling (us) */
+ bool throttled; /* whether current transaction was throttled */
int use_file; /* index in sql_files for this client */
bool prepared[MAX_FILES];
} CState;
@@ -346,6 +354,9 @@ usage(void)
" -D VARNAME=VALUE\n"
" define variable for use by custom script\n"
" -f FILENAME read transaction script from FILENAME\n"
+ " -H SPEC, --throttle SPEC\n"
+ " delay in second to throttle each client\n"
+ " sample specs: 0.025 40tps 25ms 25000us\n"
" -j NUM number of threads (default: 1)\n"
" -l write transaction times to log file\n"
" -M simple|extended|prepared\n"
@@ -899,6 +910,27 @@ doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile, AggVa
top:
commands = sql_files[st->use_file];
+ /* handle throttling once per transaction by inserting a sleep.
+ * this is simpler than doing it at the end.
+ */
+ if (throttle && ! st->throttled)
+ {
+ /* compute delay to approximate a Poisson distribution
+ * 1000000 => 13.8 .. 0 multiplier
+ * if transactions are too slow or a given wait shorter than
+ * a transaction, the next transaction will start right away.
+ */
+ int64 wait = (int64)
+ throttle * -log(getrand(thread, 1, 1000000)/1000000.0);
+ st->trigger += wait;
+ st->sleeping = 1;
+ st->until = st->trigger;
+ st->throttled = true;
+ if (debug)
+ fprintf(stderr, "client %d throttling "INT64_FORMAT" us\n",
+ st->id, wait);
+ }
+
if (st->sleeping)
{ /* are we sleeping? */
instr_time now;
@@ -1069,6 +1101,7 @@ top:
st->state = 0;
st->use_file = (int) getrand(thread, 0, num_files - 1);
commands = sql_files[st->use_file];
+ st->throttled = false;
}
}
@@ -2086,6 +2119,7 @@ main(int argc, char **argv)
{"unlogged-tables", no_argument, &unlogged_tables, 1},
{"sampling-rate", required_argument, NULL, 4},
{"aggregate-interval", required_argument, NULL, 5},
+ {"throttle", required_argument, NULL, 'H'},
{NULL, 0, NULL, 0}
};
@@ -2152,7 +2186,7 @@ main(int argc, char **argv)
state = (CState *) pg_malloc(sizeof(CState));
memset(state, 0, sizeof(CState));
- while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:", long_options, &optindex)) != -1)
+ while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:H:", long_options, &optindex)) != -1)
{
switch (c)
{
@@ -2307,6 +2341,26 @@ main(int argc, char **argv)
exit(1);
}
break;
+ case 'H':
+ {
+ /* get a double from the beginning of option value */
+ double throttle_value = atof(optarg);
+ if (throttle_value <= 0.0)
+ {
+ fprintf(stderr, "invalid throttle value: %s\n", optarg);
+ exit(1);
+ }
+ /* rough handling of possible units */
+ if (strstr(optarg, "us"))
+ throttle = (int64) throttle_value;
+ else if (strstr(optarg, "ms"))
+ throttle = (int64) (1000.0 * throttle_value);
+ else if (strstr(optarg, "tps"))
+ throttle = (int64) (1000000.0 / throttle_value);
+ else /* assume that default is in second */
+ throttle = (int64) (1000000.0 * throttle_value);
+ }
+ break;
case 0:
/* This covers long options which take no argument. */
break;
@@ -2594,6 +2648,14 @@ main(int argc, char **argv)
/* get start up time */
INSTR_TIME_SET_CURRENT(start_time);
+ /* set initial client throttling trigger */
+ if (throttle)
+ {
+ state[0].trigger = INSTR_TIME_GET_MICROSEC(start_time);
+ for (i = 1; i < nclients; i++)
+ state[i].trigger = state[0].trigger;
+ }
+
/* set alarm if duration is specified. */
if (duration > 0)
setalarm(duration);
diff --git a/doc/src/sgml/pgbench.sgml b/doc/src/sgml/pgbench.sgml
index 79b4baf..1ba24b5 100644
--- a/doc/src/sgml/pgbench.sgml
+++ b/doc/src/sgml/pgbench.sgml
@@ -310,6 +310,26 @@ pgbench <optional> <replaceable>options</> </optional> <replaceable>dbname</>
</varlistentry>
<varlistentry>
+ <term><option>-H</option> <replaceable>rate</></term>
+ <term><option>--throttle</option> <replaceable>rate</></term>
+ <listitem>
+ <para>
+ Do client transaction throttling at the specified rate instead of
+ maximizing the load.
+ Each client connection targets this rate by starting transactions
+ along a Poisson-distributed event time line.
+ Obviously, the targeted rate must be below the maximum possible rate
+ of the system.
+ Example equivalent <replaceable>rate</> specifications which aim at
+ 40 transactions-per-second, that is one transaction every 25 ms:
+ <literal>0.025</>, <literal>0.025s</>, <literal>25ms</>,
+ <literal>25000us</> and finally <literal>40tps</>.
+ Default is no throttling.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
<term><option>-j</option> <replaceable>threads</></term>
<listitem>
<para>
--
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