*/
int64 throttle_delay = 0;
+/*
+ * Transactions which take longer than this limit (in usec) are counted as
+ * late, and reported as such, although they are completed anyway. When
+ * throttling is enabled, execution time slots that are more than this late
+ * are skipped altogether, and counted separately.
+ */
+int64 latency_limit = 0;
+
/*
* tablespace selection
*/
int64 throttle_trigger; /* previous/next throttling (us) */
int64 throttle_lag; /* total transaction lag behind throttling */
int64 throttle_lag_max; /* max transaction lag */
+ int64 throttle_latency_skipped; /* lagging transactions skipped */
+ int64 latency_late; /* late transactions */
} TState;
#define INVALID_THREAD ((pthread_t) 0)
int64 sqlats;
int64 throttle_lag;
int64 throttle_lag_max;
+ int64 throttle_latency_skipped;
+ int64 latency_late;
} TResult;
/*
long start_time; /* when does the interval start */
int cnt; /* number of transactions */
+ int skipped; /* number of transactions skipped under
+ * --rate and --latency-limit */
double min_latency; /* min/max latencies */
double max_latency;
static void *threadRun(void *arg);
static void doLog(TState *thread, CState *st, FILE *logfile, instr_time *now,
- AggVals *agg);
+ AggVals *agg, bool skipped );
static void
usage(void)
" -f, --file=FILENAME read transaction script from FILENAME\n"
" -j, --jobs=NUM number of threads (default: 1)\n"
" -l, --log write transaction times to log file\n"
+ " -L, --latency-limit=NUM count transactions lasting more than NUM ms\n"
+ " as late.\n"
" -M, --protocol=simple|extended|prepared\n"
" protocol for submitting queries (default: simple)\n"
" -n, --no-vacuum do not run VACUUM before tests\n"
agg_vals_init(AggVals *aggs, instr_time start)
{
/* basic counters */
- aggs->cnt = 0; /* number of transactions */
+ aggs->cnt = 0; /* number of transactions (includes skipped) */
+ aggs->skipped = 0; /* xacts skipped under --rate --latency-limit */
+
aggs->sum_latency = 0; /* SUM(latency) */
aggs->sum2_latency = 0; /* SUM(latency*latency) */
int64 wait = getPoissonRand(thread, throttle_delay);
thread->throttle_trigger += wait;
-
st->txn_scheduled = thread->throttle_trigger;
+
+ /*
+ * If this --latency-limit is used, and this slot is already late so
+ * that the transaction will miss the latency limit even if it
+ * completed immediately, we skip this time slot and iterate till the
+ * next slot that isn't late yet.
+ */
+ if (latency_limit)
+ {
+ int64 now_us;
+
+ if (INSTR_TIME_IS_ZERO(now))
+ INSTR_TIME_SET_CURRENT(now);
+ now_us = INSTR_TIME_GET_MICROSEC(now);
+ while (thread->throttle_trigger < now_us - latency_limit)
+ {
+ thread->throttle_latency_skipped++;
+
+ if (logfile)
+ doLog(thread, st, logfile, &now, agg, true);
+
+ wait = getPoissonRand(thread, throttle_delay);
+ thread->throttle_trigger += wait;
+ st->txn_scheduled = thread->throttle_trigger;
+ }
+ }
+
st->sleeping = 1;
st->throttling = true;
st->is_throttled = true;
if (commands[st->state + 1] == NULL)
{
/* only calculate latency if an option is used that needs it */
- if (progress || throttle_delay)
+ if (progress || throttle_delay || latency_limit )
{
int64 latency;
if (INSTR_TIME_IS_ZERO(now))
INSTR_TIME_SET_CURRENT(now);
+
latency = INSTR_TIME_GET_MICROSEC(now) - st->txn_scheduled;
st->txn_latencies += latency;
* transactions, overflow would take 256 hours.
*/
st->txn_sqlats += latency * latency;
+
+ /* record over the limit transactions if needed. */
+ if (latency_limit && latency > latency_limit)
+ thread->latency_late++;
}
/* record the time it took in the log */
if (logfile)
- doLog(thread, st, logfile, &now, agg);
+ doLog(thread, st, logfile, &now, agg, false );
}
if (commands[st->state]->type == SQL_COMMAND)
}
/* Record transaction start time under logging, progress or throttling */
- if ((logfile || progress || throttle_delay) && st->state == 0)
+ if ((logfile || progress || throttle_delay || latency_limit ) && st->state == 0)
{
INSTR_TIME_SET_CURRENT(st->txn_begin);
* print log entry after completing one transaction.
*/
static void
-doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg)
+doLog(TState *thread, CState *st, FILE *logfile, instr_time *now, AggVals *agg,
+ bool skipped)
{
double lag;
double latency;
INSTR_TIME_SET_CURRENT(*now);
latency = (double) (INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled);
- lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
+ if (skipped)
+ lag = latency;
+ else
+ lag = (double) (INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled);
/* should we aggregate the results or not? */
if (agg_interval > 0)
if (agg->start_time + agg_interval >= INSTR_TIME_GET_DOUBLE(*now))
{
agg->cnt += 1;
- agg->sum_latency += latency;
- agg->sum2_latency += latency * latency;
+ if (skipped)
+ {
+ /* there is no latency to record if the transaction was skipped */
+ agg->skipped += 1;
+ }
+ else
+ {
+ agg->sum_latency += latency;
+ agg->sum2_latency += latency * latency;
- /* first in this aggregation interval */
- if ((agg->cnt == 1) || (latency < agg->min_latency))
- agg->min_latency = latency;
+ /* first in this aggregation interval */
+ if ((agg->cnt == 1) || (latency < agg->min_latency))
+ agg->min_latency = latency;
- if ((agg->cnt == 1) || (latency > agg->max_latency))
- agg->max_latency = latency;
+ if ((agg->cnt == 1) || (latency > agg->max_latency))
+ agg->max_latency = latency;
- /* and the same for schedule lag */
- if (throttle_delay)
- {
- agg->sum_lag += lag;
- agg->sum2_lag += lag * lag;
+ /* and the same for schedule lag */
+ if (throttle_delay)
+ {
+ agg->sum_lag += lag;
+ agg->sum2_lag += lag * lag;
- if ((agg->cnt == 1) || (lag < agg->min_lag))
- agg->min_lag = lag;
- if ((agg->cnt == 1) || (lag > agg->max_lag))
- agg->max_lag = lag;
+ if ((agg->cnt == 1) || (lag < agg->min_lag))
+ agg->min_lag = lag;
+ if ((agg->cnt == 1) || (lag > agg->max_lag))
+ agg->max_lag = lag;
+ }
}
}
else
agg->min_latency,
agg->max_latency);
if (throttle_delay)
+ {
fprintf(logfile, " %.0f %.0f %.0f %.0f",
agg->sum_lag,
agg->sum2_lag,
agg->min_lag,
agg->max_lag);
+ if (latency_limit)
+ fprintf(logfile, " %d", agg->skipped);
+ }
fputc('\n', logfile);
/* move to the next inteval */
/* reset for "no transaction" intervals */
agg->cnt = 0;
+ agg->skipped = 0;
agg->min_latency = 0;
agg->max_latency = 0;
agg->sum_latency = 0;
/* reset the values to include only the current transaction. */
agg->cnt = 1;
+ agg->skipped = skipped ? 1 : 0;
agg->min_latency = latency;
agg->max_latency = latency;
- agg->sum_latency = latency;
- agg->sum2_latency = latency * latency;
+ agg->sum_latency = skipped ? 0.0 : latency;
+ agg->sum2_latency = skipped ? 0.0 : latency * latency;
agg->min_lag = lag;
agg->max_lag = lag;
agg->sum_lag = lag;
#ifndef WIN32
/* This is more than we really ought to know about instr_time */
- fprintf(logfile, "%d %d %.0f %d %ld %ld",
- st->id, st->cnt, latency, st->use_file,
- (long) now->tv_sec, (long) now->tv_usec);
+ if (skipped)
+ fprintf(logfile, "%d %d skipped %d %ld %ld",
+ st->id, st->cnt, st->use_file,
+ (long) now->tv_sec, (long) now->tv_usec);
+ else
+ fprintf(logfile, "%d %d %.0f %d %ld %ld",
+ st->id, st->cnt, latency, st->use_file,
+ (long) now->tv_sec, (long) now->tv_usec);
#else
/* On Windows, instr_time doesn't provide a timestamp anyway */
- fprintf(logfile, "%d %d %.0f %d 0 0",
- st->id, st->cnt, latency, st->use_file);
+ if (skipped)
+ fprintf(logfile, "%d %d skipped %d 0 0",
+ st->id, st->cnt, st->use_file);
+ else
+ fprintf(logfile, "%d %d %.0f %d 0 0",
+ st->id, st->cnt, latency, st->use_file);
#endif
if (throttle_delay)
fprintf(logfile, " %.0f", lag);
TState *threads, int nthreads,
instr_time total_time, instr_time conn_total_time,
int64 total_latencies, int64 total_sqlats,
- int64 throttle_lag, int64 throttle_lag_max)
+ int64 throttle_lag, int64 throttle_lag_max,
+ int64 throttle_latency_skipped, int64 latency_late)
{
double time_include,
tps_include,
normal_xacts);
}
- if (throttle_delay || progress)
+ if (throttle_delay && latency_limit)
+ printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
+ throttle_latency_skipped,
+ 100.0 * throttle_latency_skipped / (throttle_latency_skipped + normal_xacts));
+
+ if (latency_limit)
+ printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT " (%.3f %%)\n",
+ latency_limit / 1000.0, latency_late,
+ 100.0 * latency_late / (throttle_latency_skipped + normal_xacts));
+
+ if (throttle_delay || progress || latency_limit)
{
/* compute and show latency average and standard deviation */
double latency = 0.001 * total_latencies / normal_xacts;
{"sampling-rate", required_argument, NULL, 4},
{"aggregate-interval", required_argument, NULL, 5},
{"rate", required_argument, NULL, 'R'},
+ {"latency-limit", required_argument, NULL, 'L'},
{NULL, 0, NULL, 0}
};
int64 total_sqlats = 0;
int64 throttle_lag = 0;
int64 throttle_lag_max = 0;
+ int64 throttle_latency_skipped = 0;
+ int64 latency_late = 0;
int i;
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:P:R:", long_options, &optindex)) != -1)
+ while ((c = getopt_long(argc, argv, "ih:nvp:dqSNc:j:Crs:t:T:U:lf:D:F:M:P:R:L: ", long_options, &optindex)) != -1)
{
switch (c)
{
throttle_delay = (int64) (1000000.0 / throttle_value);
}
break;
+ case 'L':
+ {
+ double limit_ms = atof(optarg);
+ if (limit_ms <= 0.0)
+ {
+ fprintf(stderr, "invalid latency limit: %s\n", optarg);
+ exit(1);
+ }
+ benchmarking_option_set = true;
+ latency_limit = (int64) (limit_ms * 1000);
+ }
+ break;
case 0:
/* This covers long options which take no argument. */
if (foreign_keys || unlogged_tables)
thread->random_state[0] = random();
thread->random_state[1] = random();
thread->random_state[2] = random();
+ thread->throttle_latency_skipped = 0;
+ thread->latency_late = 0;
if (is_latencies)
{
total_latencies += r->latencies;
total_sqlats += r->sqlats;
throttle_lag += r->throttle_lag;
+ throttle_latency_skipped += r->throttle_latency_skipped;
+ latency_late += r->latency_late;
if (r->throttle_lag_max > throttle_lag_max)
throttle_lag_max = r->throttle_lag_max;
INSTR_TIME_ADD(conn_total_time, r->conn_time);
INSTR_TIME_SUBTRACT(total_time, start_time);
printResults(ttype, total_xacts, nclients, threads, nthreads,
total_time, conn_total_time, total_latencies, total_sqlats,
- throttle_lag, throttle_lag_max);
+ throttle_lag, throttle_lag_max, throttle_latency_skipped,
+ latency_late);
return 0;
}
int64 last_count = 0,
last_lats = 0,
last_sqlats = 0,
- last_lags = 0;
+ last_lags = 0,
+ last_skipped = 0;
AggVals aggs;
/* generate and show report */
int64 count = 0,
lats = 0,
- sqlats = 0;
+ sqlats = 0,
+ skipped = 0;
int64 lags = thread->throttle_lag;
int64 run = now - last_report;
double tps,
sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
lag = 0.001 * (lags - last_lags) / (count - last_count);
+ skipped = thread->throttle_latency_skipped - last_skipped;
+ fprintf(stderr,
+ "progress %d: %.1f s, %.1f tps, "
+ "lat %.3f ms stddev %.3f",
+ thread->tid, total_run, tps, latency, stdev);
if (throttle_delay)
- fprintf(stderr,
- "progress %d: %.1f s, %.1f tps, "
- "lat %.3f ms stddev %.3f, lag %.3f ms\n",
- thread->tid, total_run, tps, latency, stdev, lag);
- else
- fprintf(stderr,
- "progress %d: %.1f s, %.1f tps, "
- "lat %.3f ms stddev %.3f\n",
- thread->tid, total_run, tps, latency, stdev);
+ {
+ fprintf(stderr, ", lag %.3f ms", lag);
+ if (latency_limit)
+ fprintf(stderr, ", skipped " INT64_FORMAT, skipped);
+ }
+ fprintf(stderr, "\n");
last_count = count;
last_lats = lats;
last_sqlats = sqlats;
last_lags = lags;
last_report = now;
+ last_skipped = thread->throttle_latency_skipped;
next_report += (int64) progress *1000000;
}
}
int64 count = 0,
lats = 0,
sqlats = 0,
- lags = 0;
+ lags = 0,
+ skipped = 0;
int64 run = now - last_report;
double tps,
total_run,
sqlat = 1.0 * (sqlats - last_sqlats) / (count - last_count);
stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
lag = 0.001 * (lags - last_lags) / (count - last_count);
+ skipped = thread->throttle_latency_skipped - last_skipped;
+ fprintf(stderr,
+ "progress: %.1f s, %.1f tps, "
+ "lat %.3f ms stddev %.3f",
+ total_run, tps, latency, stdev);
if (throttle_delay)
- fprintf(stderr,
- "progress: %.1f s, %.1f tps, "
- "lat %.3f ms stddev %.3f, lag %.3f ms\n",
- total_run, tps, latency, stdev, lag);
- else
- fprintf(stderr,
- "progress: %.1f s, %.1f tps, "
- "lat %.3f ms stddev %.3f\n",
- total_run, tps, latency, stdev);
+ {
+ fprintf(stderr, ", lag %.3f ms", lag);
+ if (latency_limit)
+ fprintf(stderr, ", " INT64_FORMAT " skipped", skipped);
+ }
+ fprintf(stderr, "\n");
last_count = count;
last_lats = lats;
last_sqlats = sqlats;
last_lags = lags;
last_report = now;
+ last_skipped = thread->throttle_latency_skipped;
next_report += (int64) progress *1000000;
}
}
}
result->throttle_lag = thread->throttle_lag;
result->throttle_lag_max = thread->throttle_lag_max;
+ result->throttle_latency_skipped = thread->throttle_latency_skipped;
+ result->latency_late = thread->latency_late;
+
INSTR_TIME_SET_CURRENT(end);
INSTR_TIME_ACCUM_DIFF(result->conn_time, end, start);
if (logfile)
+
+ -L limit
+ --latency-limit= limit
+
+ Transaction which last more than limit milliseconds
+ are counted and reported separately, as late.
+
+ When throttling is used (--rate=...), transactions that
+ lag behind schedule by more than limit ms, and thus
+ have no hope of meeting the latency limit, are not sent to the server
+ at all. They are counted and reported separately as
+ skipped.
+
+
+
+
-M querymode
--protocol= querymode
latency.
+ If --latency-limit is used together with --rate,
+ a transaction can lag behind so much that it is already over the
+ latency limit when the previous transaction ends, because the latency
+ is calculated from the scheduled start time. Such transactions are
+ not sent to the server, but are skipped altogether and counted
+ separately.
+
+
A high schedule lag time is an indication that the system cannot
process transactions at the specified rate, with the chosen number of
The format of the log is:
-client_id transaction_no time file_no time_epoch time_us [schedule_lag ]
+client_id transaction_no time file_no time_epoch time_us schedule_lag
where time is the total elapsed transaction time in microseconds,
UNIX epoch format timestamp and an offset
in microseconds (suitable for creating an ISO 8601
timestamp with fractional seconds) showing when
- the transaction completed. The last field, schedule_lag, is
- the difference between the transaction's scheduled start time, and the
- time it actually started, in microseconds. It is only present when the
- --rate option is used.
+ the transaction completed.
+ Field schedule_lag is the difference between the
+ transaction's scheduled start time, and the time it actually started, in
+ microseconds. It is only present when the --rate option is used.
+ The last field skipped_transactions reports the number of
+ transactions skipped because they were too far behind schedule. It is only
+ present when both options --rate and --latency-limit
+ are used.
- Here are example outputs :
+ Here is a snippet of the log file generated :
0 199 2241 0 1175850568 995598
0 200 2465 0 1175850568 998079
0 201 2513 0 1175850569 608
0 202 2038 0 1175850569 2663
-
+
+
+ Another example with --rate=100 and --latency-limit=5 (note the additional
+ schedule_lag column):
+
+ 0 81 4621 0 1412881037 912698 3005
+ 0 82 6173 0 1412881037 914578 4304
+ 0 83 skipped 0 1412881037 914578 5217
+ 0 83 skipped 0 1412881037 914578 5099
+ 0 83 4722 0 1412881037 916203 3108
+ 0 84 4142 0 1412881037 918023 2333
+ 0 85 2465 0 1412881037 919759 740
+
+ In this example, transaction 82 was late, because it's latency (6.173 ms) was
+ over the 5 ms limit. The next two transactions were skipped, because they
+ were already late before they were even started.
+
When running a long test on hardware that can handle a lot of transactions,
With the --aggregate-interval option, the logs use a bit different format:
-interval_start num_of_transactions latency_sum latency_2_sum min_latency max_latency [lag_sum lag_2_sum min_lag max_lag]
+interval_start num_of_transactions latency_sum latency_2_sum min_latency max_latency lag_sum lag_2_sum min_lag max_lag skipped_transactions
where interval_start is the start of the interval (UNIX epoch
latency_2_sum is a sum of 2nd powers of latencies. The last two
fields are min_latency - a minimum latency within the interval, and
max_latency - maximum latency within the interval. A transaction is
- counted into the interval when it was committed. The last four fields,
- lag_sum, lag_2_sum, min_lag, and max_lag, are only present if the --rate option is used.
+ counted into the interval when it was committed. The fields in the end,
+ lag_sum, lag_2_sum, min_lag,
+ and max_lag, are only present if the --rate
+ option is used. The very last one, skipped_transactions,
+ is only present if the option --latency-limit is present, too.
They are calculated from the time each transaction had to wait for the
previous one to finish, i.e. the difference between each transaction's
scheduled start time and the time it actually started.
projects / postgresql.git / commitdiff