On 7/14/13 2:48 PM, Fabien COELHO wrote:
You attached my v13. Could you send your v14?
Correct patch (and the little one from me again) attached this time.
--
Greg Smith 2ndQuadrant US g...@2ndquadrant.com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.com
diff --git a/contrib/pgbench/pgbench.c b/contrib/pgbench/pgbench.c
new file mode 100644
index 08095a9..6564057
*** a/contrib/pgbench/pgbench.c
--- b/contrib/pgbench/pgbench.c
*************** int unlogged_tables = 0;
*** 137,142 ****
--- 137,148 ----
double sample_rate = 0.0;
/*
+ * When threads are throttled to a given rate limit, this is the target delay
+ * to reach that rate in usec. 0 is the default and means no throttling.
+ */
+ int64 throttle_delay = 0;
+
+ /*
* tablespace selection
*/
char *tablespace = NULL;
*************** typedef struct
*** 200,210 ****
--- 206,218 ----
int listen; /* 0 indicates that an
async query has been
* sent */
int sleeping; /* 1 indicates that the
client is napping */
+ bool throttling; /* whether nap is for throttling */
int64 until; /* napping until (usec) */
Variable *variables; /* array of variable definitions */
int nvariables;
instr_time txn_begin; /* used for measuring
transaction latencies */
instr_time stmt_begin; /* used for measuring statement
latencies */
+ bool is_throttled; /* whether transaction should be
throttled */
int use_file; /* index in sql_files
for this client */
bool prepared[MAX_FILES];
} CState;
*************** typedef struct
*** 222,227 ****
--- 230,238 ----
instr_time *exec_elapsed; /* time spent executing cmds (per
Command) */
int *exec_count; /* number of cmd executions
(per Command) */
unsigned short random_state[3]; /* separate randomness for each
thread */
+ int64 throttle_trigger; /* previous/next throttling (us) */
+ int64 throttle_lag; /* total transaction lag behind
throttling */
+ int64 throttle_lag_max; /* max transaction lag */
} TState;
#define INVALID_THREAD ((pthread_t) 0)
*************** typedef struct
*** 230,235 ****
--- 241,248 ----
{
instr_time conn_time;
int xacts;
+ int64 throttle_lag;
+ int64 throttle_lag_max;
} TResult;
/*
*************** usage(void)
*** 353,358 ****
--- 366,372 ----
" -n, --no-vacuum do not run VACUUM before tests\n"
" -N, --skip-some-updates skip updates of pgbench_tellers
and pgbench_branches\n"
" -r, --report-latencies report average latency per
command\n"
+ " -R, --rate SPEC target rate in transactions per
second\n"
" -s, --scale=NUM report this scale factor in
output\n"
" -S, --select-only perform SELECT-only
transactions\n"
" -t, --transactions number of transactions each
client runs "
*************** doCustom(TState *thread, CState *st, ins
*** 900,916 ****
{
PGresult *res;
Command **commands;
top:
commands = sql_files[st->use_file];
if (st->sleeping)
{ /* are we
sleeping? */
instr_time now;
INSTR_TIME_SET_CURRENT(now);
! if (st->until <= INSTR_TIME_GET_MICROSEC(now))
st->sleeping = 0; /* Done sleeping, go ahead with
next command */
else
return true; /* Still sleeping, nothing to
do here */
}
--- 914,973 ----
{
PGresult *res;
Command **commands;
+ bool trans_needs_throttle = false;
top:
commands = sql_files[st->use_file];
+ /*
+ * Handle throttling once per transaction by sleeping. It is simpler
+ * to do this here rather than at the end, because so much complicated
+ * logic happens below when statements finish.
+ */
+ if (throttle_delay && ! st->is_throttled)
+ {
+ /*
+ * Use inverse transform sampling to randomly generate a delay,
such
+ * that the series of delays will approximate a Poisson
distribution
+ * centered on the throttle_delay time.
+ *
+ * If transactions are too slow or a given wait is shorter than
+ * a transaction, the next transaction will start right away.
+ */
+ int64 wait = (int64)
+ throttle_delay * -log(getrand(thread, 1, 1000)/1000.0);
+
+ thread->throttle_trigger += wait;
+
+ st->until = thread->throttle_trigger;
+ st->sleeping = 1;
+ st->throttling = true;
+ st->is_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;
+ int64 now_us;
INSTR_TIME_SET_CURRENT(now);
! now_us = INSTR_TIME_GET_MICROSEC(now);
! if (st->until <= now_us)
! {
st->sleeping = 0; /* Done sleeping, go ahead with
next command */
+ if (st->throttling)
+ {
+ /* Measure lag of throttled transaction
relative to target */
+ int64 lag = now_us - st->until;
+ thread->throttle_lag += lag;
+ if (lag > thread->throttle_lag_max)
+ thread->throttle_lag_max = lag;
+ st->throttling = false;
+ }
+ }
else
return true; /* Still sleeping, nothing to
do here */
}
*************** top:
*** 1097,1102 ****
--- 1154,1168 ----
st->state = 0;
st->use_file = (int) getrand(thread, 0, num_files - 1);
commands = sql_files[st->use_file];
+ st->is_throttled = false;
+ /*
+ * No transaction is underway anymore, which means
there is nothing
+ * to listen to right now. When throttling rate limits
are active,
+ * a sleep will happen next, as the next transaction
starts. And
+ * then in any case the next SQL command will set
listen back to 1.
+ */
+ st->listen = 0;
+ trans_needs_throttle = (throttle_delay>0);
}
}
*************** top:
*** 1115,1120 ****
--- 1181,1195 ----
INSTR_TIME_ACCUM_DIFF(*conn_time, end, start);
}
+ /*
+ * This won't add a throttling delay during the first transaction after
+ * opening a connection. They will be inserted starting with the
second.
+ */
+ if (trans_needs_throttle) {
+ trans_needs_throttle = false;
+ goto top;
+ }
+
/* Record transaction start time if logging is enabled */
if (logfile && st->state == 0)
INSTR_TIME_SET_CURRENT(st->txn_begin);
*************** process_builtin(char *tb)
*** 2019,2025 ****
static void
printResults(int ttype, int normal_xacts, int nclients,
TState *threads, int nthreads,
! instr_time total_time, instr_time conn_total_time)
{
double time_include,
tps_include,
--- 2094,2101 ----
static void
printResults(int ttype, int normal_xacts, int nclients,
TState *threads, int nthreads,
! instr_time total_time, instr_time conn_total_time,
! int64 throttle_lag, int64 throttle_lag_max)
{
double time_include,
tps_include,
*************** printResults(int ttype, int normal_xacts
*** 2057,2062 ****
--- 2133,2151 ----
printf("number of transactions actually processed: %d\n",
normal_xacts);
}
+
+ if (throttle_delay)
+ {
+ /*
+ * Report average transaction lag under rate limit throttling.
This
+ * is the delay between scheduled and actual start times for the
+ * transaction. The measured lag may be caused by
thread/client load,
+ * the database load, or the Poisson throttling process.
+ */
+ printf("average rate limit lag: %.3f ms (max %.3f ms)\n",
+ 0.001 * throttle_lag / normal_xacts, 0.001 *
throttle_lag_max);
+ }
+
printf("tps = %f (including connections establishing)\n", tps_include);
printf("tps = %f (excluding connections establishing)\n", tps_exclude);
*************** main(int argc, char **argv)
*** 2141,2146 ****
--- 2230,2236 ----
{"unlogged-tables", no_argument, &unlogged_tables, 1},
{"sampling-rate", required_argument, NULL, 4},
{"aggregate-interval", required_argument, NULL, 5},
+ {"rate", required_argument, NULL, 'R'},
{NULL, 0, NULL, 0}
};
*************** main(int argc, char **argv)
*** 2163,2168 ****
--- 2253,2260 ----
instr_time total_time;
instr_time conn_total_time;
int total_xacts;
+ int64 throttle_lag = 0;
+ int64 throttle_lag_max = 0;
int i;
*************** main(int argc, char **argv)
*** 2207,2213 ****
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)
{
switch (c)
{
--- 2299,2305 ----
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:R:", long_options, &optindex)) != -1)
{
switch (c)
{
*************** main(int argc, char **argv)
*** 2362,2367 ****
--- 2454,2472 ----
exit(1);
}
break;
+ case 'R':
+ {
+ /* get a double from the beginning of option
value */
+ double throttle_value = atof(optarg);
+ if (throttle_value <= 0.0)
+ {
+ fprintf(stderr, "invalid rate limit:
%s\n", optarg);
+ exit(1);
+ }
+ /* Invert rate limit into a time offset */
+ throttle_delay = (int64) (1000000.0 /
throttle_value);
+ }
+ break;
case 0:
/* This covers long options which take no
argument. */
break;
*************** main(int argc, char **argv)
*** 2399,2404 ****
--- 2504,2512 ----
}
}
+ /* compute a per thread delay */
+ throttle_delay *= nthreads;
+
if (argc > optind)
dbName = argv[optind];
else
*************** main(int argc, char **argv)
*** 2711,2716 ****
--- 2819,2827 ----
TResult *r = (TResult *) ret;
total_xacts += r->xacts;
+ throttle_lag += r->throttle_lag;
+ if (r->throttle_lag_max > throttle_lag_max)
+ throttle_lag_max = r->throttle_lag_max;
INSTR_TIME_ADD(conn_total_time, r->conn_time);
free(ret);
}
*************** main(int argc, char **argv)
*** 2721,2727 ****
INSTR_TIME_SET_CURRENT(total_time);
INSTR_TIME_SUBTRACT(total_time, start_time);
printResults(ttype, total_xacts, nclients, threads, nthreads,
! total_time, conn_total_time);
return 0;
}
--- 2832,2838 ----
INSTR_TIME_SET_CURRENT(total_time);
INSTR_TIME_SUBTRACT(total_time, start_time);
printResults(ttype, total_xacts, nclients, threads, nthreads,
! total_time, conn_total_time, throttle_lag,
throttle_lag_max);
return 0;
}
*************** threadRun(void *arg)
*** 2741,2746 ****
--- 2852,2868 ----
AggVals aggs;
+ /*
+ * Initialize throttling rate target for all of the thread's clients.
It
+ * might be a little more accurate to reset thread->start_time here too.
+ * The possible drift seems too small relative to typical throttle delay
+ * times to worry about it.
+ */
+ INSTR_TIME_SET_CURRENT(start);
+ thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
+ thread->throttle_lag = 0;
+ thread->throttle_lag_max = 0;
+
result = pg_malloc(sizeof(TResult));
INSTR_TIME_SET_ZERO(result->conn_time);
*************** threadRun(void *arg)
*** 2816,2840 ****
Command **commands = sql_files[st->use_file];
int sock;
! if (st->sleeping)
{
! int this_usec;
!
! if (min_usec == INT64_MAX)
{
! instr_time now;
!
! INSTR_TIME_SET_CURRENT(now);
! now_usec = INSTR_TIME_GET_MICROSEC(now);
}
! this_usec = st->until - now_usec;
! if (min_usec > this_usec)
! min_usec = this_usec;
! }
! else if (st->con == NULL)
! {
! continue;
}
else if (commands[st->state]->type == META_COMMAND)
{
--- 2938,2975 ----
Command **commands = sql_files[st->use_file];
int sock;
! if (st->con == NULL)
{
! continue;
! }
! else if (st->sleeping)
! {
! if (st->throttling && timer_exceeded)
{
! /* interrupt client which has not
started a transaction */
! remains--;
! st->sleeping = 0;
! st->throttling = false;
! PQfinish(st->con);
! st->con = NULL;
! continue;
}
+ else /* just a nap from the script */
+ {
+ int this_usec;
! if (min_usec == INT64_MAX)
! {
! instr_time now;
!
! INSTR_TIME_SET_CURRENT(now);
! now_usec =
INSTR_TIME_GET_MICROSEC(now);
! }
!
! this_usec = st->until - now_usec;
! if (min_usec > this_usec)
! min_usec = this_usec;
! }
}
else if (commands[st->state]->type == META_COMMAND)
{
*************** done:
*** 2909,2914 ****
--- 3044,3051 ----
result->xacts = 0;
for (i = 0; i < nstate; i++)
result->xacts += state[i].cnt;
+ result->throttle_lag = thread->throttle_lag;
+ result->throttle_lag_max = thread->throttle_lag_max;
INSTR_TIME_SET_CURRENT(end);
INSTR_TIME_ACCUM_DIFF(result->conn_time, end, start);
if (logfile)
diff --git a/doc/src/sgml/pgbench.sgml b/doc/src/sgml/pgbench.sgml
new file mode 100644
index a7f41e1..a6ab1bc
*** a/doc/src/sgml/pgbench.sgml
--- b/doc/src/sgml/pgbench.sgml
*************** pgbench <optional> <replaceable>options<
*** 408,413 ****
--- 408,434 ----
</varlistentry>
<varlistentry>
+ <term><option>-R</option> <replaceable>rate</></term>
+ <term><option>--rate</option> <replaceable>rate</></term>
+ <listitem>
+ <para>
+ Execute transactions targeting the specified rate instead of
+ running as fast as possible (the default). The rate is given in
+ transactions per second. If the targeted rate is
+ above the maximum possible rate these transactions can execute at,
+ the rate limit won't have any impact on results.
+
+ The rate is targeted by starting transactions along a
+ Poisson-distributed event time line. When a rate limit is
+ active, the average and maximum transaction lag time
+ (the delay between the scheduled and actual transaction start times)
+ are reported in ms. High values indicate that the database
+ could not handle the scheduled load at some time.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
<term><option>-s</option> <replaceable>scale_factor</></term>
<term><option>--scale=</option><replaceable>scale_factor</></term>
<listitem>
diff --git a/contrib/pgbench/pgbench.c b/contrib/pgbench/pgbench.c
new file mode 100644
index 08095a9..8dc81e5
*** a/contrib/pgbench/pgbench.c
--- b/contrib/pgbench/pgbench.c
*************** preparedStatementName(char *buffer, int
*** 862,875 ****
static bool
clientDone(CState *st, bool ok)
{
! /*
! * When the connection finishes normally, don't call PQfinish yet.
! * PQfinish can cause significant delays in other clients that are
! * still running. Rather than finishing all of them here, in the
! * normal case clients are instead closed in bulk by disconnect_all,
! * after they have all stopped.
! */
! if ((st->con != NULL) && ok)
{
PQfinish(st->con);
st->con = NULL;
--- 862,870 ----
static bool
clientDone(CState *st, bool ok)
{
! (void) ok; /* unused */
!
! if (st->con != NULL)
{
PQfinish(st->con);
st->con = NULL;
--
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