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PG-172: Exponential histogram for time buckets.

pull/72/head
Ibrar Ahmed 2021-02-02 15:30:28 +00:00
parent 8fea207cbf
commit 12ba1e39d1
4 changed files with 121 additions and 39 deletions
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56
guc.c
View File

@ -18,7 +18,7 @@
#include "pg_stat_monitor.h"
GucVariable conf[12];
GucVariable conf[13];
/*
* Define (or redefine) custom GUC variables.
@ -87,19 +87,27 @@ init_guc(void)
};
conf[i++] = (GucVariable) {
.guc_name = "pg_stat_monitor.pgsm_respose_time_lower_bound",
.guc_name = "pg_stat_monitor.pgsm_histogram_min",
.guc_desc = "Sets the time in millisecond.",
.guc_default = 1,
.guc_min = 1,
.guc_default = 0,
.guc_min = 0,
.guc_max = INT_MAX,
.guc_restart = true
};
conf[i++] = (GucVariable) {
.guc_name = "pg_stat_monitor.pgsm_histogram_max",
.guc_desc = "Sets the time in millisecond.",
.guc_default = 10,
.guc_min = 10,
.guc_max = INT_MAX,
.guc_restart = true
};
conf[i++] = (GucVariable) {
.guc_name = "pg_stat_monitor.pgsm_respose_time_step",
.guc_desc = "Sets the response time steps in millisecond.",
.guc_default = 1,
.guc_min = 1,
.guc_name = "pg_stat_monitor.pgsm_histogram_buckets",
.guc_desc = "Sets the maximum number of histogram buckets",
.guc_default = 10,
.guc_min = 2,
.guc_max = INT_MAX,
.guc_restart = true
};
@ -208,13 +216,12 @@ init_guc(void)
NULL,
NULL);
DefineCustomIntVariable("pg_stat_monitor.pgsm_respose_time_lower_bound",
DefineCustomIntVariable("pg_stat_monitor.pgsm_histogram_min",
"Sets the time in millisecond.",
NULL,
&PGSM_RESPOSE_TIME_LOWER_BOUND,
1,
1,
&PGSM_HISTOGRAM_MIN,
0,
0,
INT_MAX,
PGC_POSTMASTER,
0,
@ -222,12 +229,25 @@ init_guc(void)
NULL,
NULL);
DefineCustomIntVariable("pg_stat_monitor.pgsm_respose_time_step",
"Sets the response time steps in millisecond.",
DefineCustomIntVariable("pg_stat_monitor.pgsm_histogram_max",
"Sets the time in millisecond.",
NULL,
&PGSM_RESPOSE_TIME_STEP,
1,
1,
&PGSM_HISTOGRAM_MAX,
10,
10,
INT_MAX,
PGC_POSTMASTER,
0,
NULL,
NULL,
NULL);
DefineCustomIntVariable("pg_stat_monitor.pgsm_histogram_buckets",
"Sets the total number of histogram buckets",
NULL,
&PGSM_HISTOGRAM_BUCKETS,
10,
2,
INT_MAX,
PGC_POSTMASTER,
0,

10
pg_stat_monitor--1.0.sql
View File

@ -14,6 +14,16 @@ RETURNS text
AS 'MODULE_PATHNAME'
LANGUAGE C PARALLEL SAFE;
CREATE FUNCTION get_histogram_timings()
RETURNS text
AS 'MODULE_PATHNAME'
LANGUAGE C PARALLEL SAFE;
CREATE FUNCTION range()
RETURNS text[] AS $$
SELECT string_to_array(get_histogram_timings(), ',');
$$ LANGUAGE SQL;
CREATE FUNCTION pg_stat_monitor(IN showtext boolean,
OUT bucket int,
OUT userid oid,

83
pg_stat_monitor.c
View File

@ -54,6 +54,7 @@ static struct rusage rusage_start;
static struct rusage rusage_end;
static unsigned char *pgss_qbuf[MAX_BUCKETS];
static int get_histogram_bucket(double q_time);
static bool IsSystemInitialized(void);
static void dump_queries_buffer(int bucket_id, unsigned char *buf, int buf_len);
static double time_diff(struct timeval end, struct timeval start);
@ -77,11 +78,12 @@ PG_FUNCTION_INFO_V1(pg_stat_monitor_1_2);
PG_FUNCTION_INFO_V1(pg_stat_monitor_1_3);
PG_FUNCTION_INFO_V1(pg_stat_monitor);
PG_FUNCTION_INFO_V1(pg_stat_monitor_settings);
PG_FUNCTION_INFO_V1(get_histogram_timings);
static uint pg_get_client_addr(void);
static int pg_get_application_name(char* application_name);
static PgBackendStatus *pg_get_backend_status(void);
static Datum textarray_get_datum(char arr[][CMD_LEN], int len);
static Datum textarray_get_datum(char arr[][1024], int len, int str_len);
static Datum intarray_get_datum(int32 arr[], int len);
#if PG_VERSION_NUM >= 130000
@ -949,16 +951,8 @@ static void pgss_store(uint64 queryId,
/* increment only in case of PGSS_EXEC */
if (kind == PGSS_EXEC)
{
for (i = 0; i < MAX_RESPONSE_BUCKET; i++)
{
if (total_time < PGSM_RESPOSE_TIME_LOWER_BOUND + (PGSM_RESPOSE_TIME_STEP * i))
{
e->counters.resp_calls[i]++;
break;
}
}
if (total_time > PGSM_RESPOSE_TIME_LOWER_BOUND + (PGSM_RESPOSE_TIME_STEP * MAX_RESPONSE_BUCKET))
e->counters.resp_calls[MAX_RESPONSE_BUCKET - 1]++;
int index = get_histogram_bucket(total_time);
e->counters.resp_calls[index]++;
}
_snprintf(e->counters.info.application_name, application_name, application_name_len, APPLICATIONNAME_LEN);
@ -1209,7 +1203,7 @@ pg_stat_monitor_internal(FunctionCallInfo fcinfo,
else
values[i++] = IntArrayGetTextDatum(tmp.info.relations, len);
values[i++] = TextArrayGetTextDatum(tmp.info.cmd_type, CMD_LST);
values[i++] = TextArrayGetTextDatum((char (*)[1024])tmp.info.cmd_type, CMD_LST, CMD_LEN);
values[i++] = Int64GetDatumFast(tmp.error.elevel);
if (strlen(tmp.error.sqlcode) <= 0)
values[i++] = CStringGetTextDatum("0");
@ -2213,9 +2207,10 @@ comp_location(const void *a, const void *b)
else
return 0;
}
/* Convert array into Text dataum */
static Datum
textarray_get_datum(char arr[][CMD_LEN], int len)
textarray_get_datum(char arr[][1024], int len, int str_len)
{
int j;
char str[1024];
@ -2226,15 +2221,15 @@ textarray_get_datum(char arr[][CMD_LEN], int len)
/* Need to calculate the actual size, and avoid unnessary memory usage */
for (j = 0; j < len; j++)
{
if (strlen(arr[j]) <= 0)
if (arr[j] == NULL || strlen(arr[j]) <= 0)
continue;
if (first)
{
snprintf(str, CMD_LEN, "%s", arr[j]);
snprintf(str, str_len, "%s", arr[j]);
first = false;
continue;
}
snprintf(str, CMD_LEN, "%s,%s", str, arr[j]);
snprintf(str, str_len, "%s,%s", str, arr[j]);
}
return CStringGetTextDatum(str);
@ -2665,3 +2660,59 @@ unpack_sql_state(int sql_state)
return buf;
}
static int
get_histogram_bucket(double q_time)
{
double q_min = PGSM_HISTOGRAM_MIN;
double q_max = PGSM_HISTOGRAM_MAX;
int b_count = PGSM_HISTOGRAM_BUCKETS;
int index = 0;
double b_max;
double b_min;
double bucket_size;
q_time -= q_min;
b_max = log(q_max - q_min);
b_min = 0;
bucket_size = (b_max - b_min) / (double)b_count;
for(index = 1; index <= b_count; index++)
{
double b_start = (index == 1)? 0 : exp(bucket_size * (index - 1));
double b_end = exp(bucket_size * index);
if( (index == 1 && q_time < b_start)
|| (q_time >= b_start && q_time <= b_end)
|| (index == b_count && q_time > b_end) )
{
return index - 1;
}
}
return 0;
}
Datum
get_histogram_timings(PG_FUNCTION_ARGS)
{
double q_min = PGSM_HISTOGRAM_MIN;
double q_max = PGSM_HISTOGRAM_MAX;
int b_count = PGSM_HISTOGRAM_BUCKETS;
int index = 0;
double b_max;
double b_min;
double bucket_size;
char range[50][1024] = {0};
b_max = log(q_max - q_min);
b_min = 0;
bucket_size = (b_max - b_min) / (double)b_count;
for(index = 1; index <= b_count; index++)
{
int64 b_start = (index == 1)? 0 : exp(bucket_size * (index - 1));
int64 b_end = exp(bucket_size * index);
sprintf(range[index-1], "(%d - %d)}", b_start, b_end);
}
return TextArrayGetTextDatum(range, b_count, 1024);
}

11
pg_stat_monitor.h
View File

@ -54,7 +54,7 @@
#include "utils/guc.h"
#define MAX_BACKEND_PROCESES (MaxBackends + NUM_AUXILIARY_PROCS + max_prepared_xacts)
#define TextArrayGetTextDatum(x,y) textarray_get_datum(x,y)
#define TextArrayGetTextDatum(x,y,z) textarray_get_datum(x,y,z)
#define IntArrayGetTextDatum(x,y) intarray_get_datum(x,y)
/* XXX: Should USAGE_EXEC reflect execution time and/or buffer usage? */
@ -341,9 +341,10 @@ void pgss_startup(void);
#define PGSM_NORMALIZED_QUERY get_conf(4)->guc_variable
#define PGSM_MAX_BUCKETS get_conf(5)->guc_variable
#define PGSM_BUCKET_TIME get_conf(6)->guc_variable
#define PGSM_RESPOSE_TIME_LOWER_BOUND get_conf(7)->guc_variable
#define PGSM_RESPOSE_TIME_STEP get_conf(8)->guc_variable
#define PGSM_QUERY_BUF_SIZE get_conf(9)->guc_variable
#define PGSM_TRACK_PLANNING get_conf(10)->guc_variable
#define PGSM_HISTOGRAM_MIN get_conf(7)->guc_variable
#define PGSM_HISTOGRAM_MAX get_conf(8)->guc_variable
#define PGSM_HISTOGRAM_BUCKETS get_conf(9)->guc_variable
#define PGSM_QUERY_BUF_SIZE get_conf(10)->guc_variable
#define PGSM_TRACK_PLANNING get_conf(11)->guc_variable
#endif