Uno dei metodi per ottenere il profilo del carico di lavoro e la storia delle attese in PostgreSQL

Continuazione dell'articolo «Tentativo di creare un equivalente di ASH per PostgreSQL «.

Nell'articolo verrà esaminato e dimostrato, con richieste specifiche ed esempi, quale utile informazione si possa ottenere tramite la vista pg_stat_activity.

Attenzione.
A causa della novità dell'argomento e del periodo di test incompleto, l'articolo potrebbe contenere errori. Critiche e osservazioni sono benvenute e attese.

Dati di input

Storia della vista pg_stat_statements

pg_stat_history

CREATE TABLE pg_stat_history ( 
id SERIAL, 
snapshot_timestamp timestamp without time zone, 
database_id integer,
dbid oid,
userid oid,
queryid bigint,
query text,
calls bigint, 
total_time double precision, 
min_time double precision, 
max_time double precision, 
mean_time double precision,
stddev_time double precision,
rows bigint,
shared_blks_hit bigint, 
shared_blks_read bigint, 
shared_blks_dirtied bigint, 
shared_blks_written bigint, 
local_blks_hit bigint, 
local_blks_read bigint,
local_blks_dirtied bigint, 
local_blks_written bigint, 
temp_blks_read bigint,
temp_blks_written bigint,
blk_read_time double precision, 
blk_write_time double precision, 
baseline_id integer );

La tabella viene popolata ogni ora, utilizzando dblink per connettersi al database di destinazione. La colonna più interessante e utile nella tabella, naturalmente, queryid.

Storia della vista pg_stat_activity

archive_pg_stat_activity

CREA TABELLA archive_pg_stat_activity
(
  timepoint timestamp senza fuso orario,
  datid             oid, 
  datname           nome,
  pid               intero,
  usesysid          oid,
  usename           nome,
  application_name  testo,
  client_addr       inet,
  client_hostname   testo,
  client_port       intero,
  backend_start     timestamp senza fuso orario,
  xact_start        timestamp senza fuso orario,
  query_start       timestamp senza fuso orario,
  state_change      timestamp senza fuso orario,
  wait_event_type   testo,                     
  wait_event        testo,                   
  state             testo,                  
  backend_xid       xid,                 
  backend_xmin      xid,                
  query             testo,               
  backend_type      testo,
  queryid           bigint
);

La tabella rappresenta una tabella history_pg_stat_activity partizionata per ore (Maggiori dettagli qui — pg_stat_statements + pg_stat_activity + loq_query = pg_ash? e qui — Tentativo di creare un'analoga ASH per PostgreSQL.)

Output

CLUSTER TEMPO CPU (SISTEMA + CLIENTI )

Richiesta

CON 
 t AS
 (
	SELEZIONA 		
			date_trunc('secondo', timepoint)
	DA 	activity_hist.archive_pg_stat_activity aa
	DOVE 	timepoint TRA pg_stat_history_begin+(current_hour_diff * intervallo '1 ora') E pg_stat_history_end+(current_hour_diff * intervallo '1 ora')  E 
			( aa.wait_event_type È NULL  ) E
			aa.state = 'attivo'
 )
 SELEZIONA count(*) 
 IN
 DA t ;

Esempio

CLUSTER TEMPO CPU (SISTEMA + CLIENTI ) : 28:37:46

CLUSTER TEMPO DI ATTESA

Richiesta

CON 
 t AS
 (
	SELEZIONA 		
			date_trunc('secondo', timepoint)
	DA 	activity_hist.archive_pg_stat_activity aa
	DOVE 	timepoint TRA pg_stat_history_begin+(current_hour_diff * intervallo '1 ora') E pg_stat_history_end+(current_hour_diff * intervallo '1 ora')  E 
			( aa.wait_event_type È NON NULL  ) E
			aa.state = 'attivo'
 )
 SELEZIONA count(*) 
 IN
 DA t ;

Esempio

CLUSTER TEMPO DI ATTESA : 30:12:49

Valori totali di pg_stat_statements

Richiesta

 --TOTALE pg_stat
  SELEZIONA 
    SUM(calls) AS calls, SUM(total_time) AS total_time, SUM(rows) AS rows ,
	SUM(shared_blks_hit) AS shared_blks_hit, SUM(shared_blks_read) AS shared_blks_read , 
	SUM(shared_blks_dirtied) AS shared_blks_dirtied, SUM(shared_blks_written) AS shared_blks_written , 
    SUM(local_blks_hit) AS local_blks_hit , SUM(local_blks_read) AS local_blks_read , 
	SUM(local_blks_dirtied) AS local_blks_dirtied , SUM(local_blks_written) AS local_blks_written,
	SUM(temp_blks_read) AS temp_blks_read, SUM(temp_blks_written) AS temp_blks_written , 
	SUM(blk_read_time) AS blk_read_time , SUM(blk_write_time) AS blk_write_time
  IN 
    pg_total_stat_history_rec
  DA 
    pg_stat_history
  DOVE 
	snapshot_timestamp TRA pg_stat_history_begin E pg_stat_history_end E 
	queryid È NULL;

SQL DBTIME — tempo totale di esecuzione delle query

Richiesta

dbtime_total = interval '1 millisecond' * pg_total_stat_history_rec.total_time ;

Esempio

SQL DBTIME : 136:49:36

SQL CPU TIME — tempo CPU speso nell'esecuzione delle query

Richiesta

CON 
 t COME
 (
	SELEZIONA 		
			date_trunc('second', timepoint)
	DA 	activity_hist.archive_pg_stat_activity aa
	DOVE 	timepoint TRA pg_stat_history_begin+(current_hour_diff * interval '1 hour') E pg_stat_history_end+(current_hour_diff * interval '1 hour')  E 
			( aa.wait_event_type È NULL ) E
			backend_type = 'client backend' E 
			aa.state = 'active'
 )
 SELEZIONA count(*) 
 IN 
 cpu_total
 DA t ;

Esempio

SQL CPU TIME : 27:40:15

SQL WAITINGS TIME — tempo totale di attesa per le query

Richiesta

CON 
 t COME
 (
	SELEZIONA 		
			date_trunc('second', timepoint)
	DA 	activity_hist.archive_pg_stat_activity aa
	DOVE 	timepoint TRA pg_stat_history_begin+(current_hour_diff * interval '1 hour') E pg_stat_history_end+(current_hour_diff * interval '1 hour')  E 
			( aa.wait_event_type È NOT NULL  ) E
			aa.state = 'active' E 
		backend_type = 'client backend'
 )
 SELEZIONA count(*) 
 IN waiting_total
 DA t ;

Esempio

TEMPI DI ATTESA SQL : 30:04:09

Le seguenti query sono triviali e per risparmiare spazio vengono omessi i dettagli di implementazione:

Esempio

| IOTIME SQL : 19:44:50
| TEMPO DI LETTURA SQL : 19:44:32
| TEMPO DI SCRITTURA SQL : 00:00:17
|
| CHIAMATE SQL : 12188248
-------------------------------------------------------------
| LETTURE DI BLOCCHI CONDIVISI SQL : 7997039120
| SUCCESSI DI BLOCCHI CONDIVISI SQL : 8868286092
| % SUCCESSI LETTURE BLOCCHI CONDIVISI SQL : 110.89
| BLOCCHI CONDIVISI SQL SPORCHI : 419945
| BLOCCHI CONDIVISI SCRITTI SQL : 19857
|
| LETTURE DI BLOCCHI TEMPORANEI SQL : 7836169
| BLOCCHI TEMPORANEI SCRITTI SQL : 10683938

Passiamo alla sezione più interessante

STATISTICHE DI ATTESA

TOP 10 ATTESE PER TEMPO TOTALE DI ATTESA NEI PROCESSI CLIENTI

Richiesta

SELEZIONA 
  wait_event_type, wait_event ,
  get_system_waiting_duration( wait_event_type , wait_event ,pg_stat_history_begin+(current_hour_diff * interval '1 hour') ,pg_stat_history_end+(current_hour_diff * interval '1 hour') ) come durata 
DA
  activity_hist.archive_pg_stat_activity aa
DOVE 
  timepoint TRA pg_stat_history_begin+(current_hour_diff * interval '1 hour') E pg_stat_history_end+(current_hour_diff * interval '1 hour') E backend_type != 'client backend' E wait_event_type È NOT NULL 
RAGGRUPPA PER 
  wait_event_type, wait_event
ORDINA PER 3 DESC
LIMITA 10

Esempio

+------------------------------------------------------------------------------------
| I 10 PROCESSI CON TEMPI DI ATTESA TOTALE
+-----+------------------------------+--------------------+--------------------
|    #|               tipo_evento_attesa|          evento_attesa|            durata
+-----+------------------------------+--------------------+--------------------
|    1|                      Attività| LogicalLauncherMain|            10:43:28
|    2|                      Attività|      AutoVacuumMain|            10:42:49
|    3|                      Attività|       WalWriterMain|            10:28:53
|    4|                      Attività|    CheckpointerMain|            10:23:50
|    5|                      Attività|        BgWriterMain|            09:11:59
|    6|                      Attività|   BgWriterHibernate|            01:37:46
|    7|                            IO|        BufFileWrite|            00:02:35
|    8|                        LWLock|      buffer_mapping|            00:01:54
|    9|                            IO|        DataFileRead|            00:01:23
|   10|                            IO|            WALWrite|            00:00:59
+-----+------------------------------+--------------------+--------------------

TOP 10 ATTESE PER TEMPO TOTALE DI ATTESA NEI PROCESSI CLIENTI

Richiesta

SELEZIONA 
  tipo_evento_attesa , evento_attesa ,
  get_clients_waiting_duration( tipo_evento_attesa , evento_attesa , pg_stat_history_begin+(current_hour_diff * interval '1 hour') , pg_stat_history_end+(current_hour_diff * interval '1 hour') ) as durata
DA 
  activity_hist.archive_pg_stat_activity aa
DOVE 
  timepoint TRA pg_stat_history_begin+(current_hour_diff * interval '1 hour') E pg_stat_history_end+(current_hour_diff * interval '1 hour') E backend_type = 'client backend' E tipo_evento_attesa È NON NULLA 
GRUPPA PER tipo_evento_attesa, evento_attesa
ORDINA PER 3 DESC
LIMIT 10

Esempio

+-----+------------------------------+--------------------+--------------------+----------
|    #|               tipo_evento_attesa|          evento_attesa|            durata|  % dbtime
+-----+------------------------------+--------------------+--------------------+----------
|    1|                          Lock|       transactionid|            08:16:47|      6.05
|    2|                            IO|        DataFileRead|            06:13:41|      4.55
|    3|                       Timeout|             PgSleep|            02:53:21|      2.11
|    4|                        LWLock|      buffer_mapping|            00:40:42|       0.5
|    5|                        LWLock|           buffer_io|            00:17:17|      0.21
|    6|                            IO|        BufFileWrite|            00:01:34|      0.02
|    7|                          Lock|               tuple|            00:01:32|      0.02
|    8|                        Client|          ClientRead|            00:01:19|      0.02
|    9|                            IO|         BufFileRead|            00:00:37|      0.01
|   10|                        LWLock|      buffer_content|            00:00:08|         0
+-----+------------------------------+--------------------+--------------------+----------

TIPI DI ATTESA PER TEMPO TOTALE DI ATTESA, PER PROCESSI DI SISTEMA

Richiesta

SELEZIONARE 
  tipo_evento_attesa ,
  get_system_waiting_type_duration( tipo_evento_attesa , pg_stat_history_begin+(current_hour_diff * interval '1 hour') , pg_stat_history_end+(current_hour_diff * interval '1 hour') ) as durata
DA
  activity_hist.archive_pg_stat_activity aa
DOVE 
  timepoint TRA pg_stat_history_begin+(current_hour_diff * interval '1 hour') E pg_stat_history_end+(current_hour_diff * interval '1 hour') E  backend_type != 'client backend' E tipo_evento_attesa è NON NULL 
GROUP BY tipo_evento_attesa
ORDINA PER 2 DESC

Esempio

+-----+------------------------------+--------------------
|    #|               wait_event_type|            duration
+-----+------------------------------+--------------------
|    1|                      Attività|            53:08:45
|    2|                            IO|            00:06:24
|    3|                        LWLock|            00:03:02
+-----+------------------------------+--------------------

TIPI DI ATTESA PER TEMPO TOTALE DI ATTESA, PER I PROCESSI CLIENTI

Richiesta

SELEZIONA 
  wait_event_type ,
  get_clients_waiting_type_duration( wait_event_type , pg_stat_history_begin+(current_hour_diff * interval '1 hour') , pg_stat_history_end+(current_hour_diff * interval '1 hour') ) as duration
DA
  activity_hist.archive_pg_stat_activity aa
DOVE 
  timepoint TRA pg_stat_history_begin+(current_hour_diff * interval '1 hour') E pg_stat_history_end+(current_hour_diff * interval '1 hour') AND backend_type = 'client backend' AND wait_event_type IS NOT NULL 
GRUPPO PER wait_event_type
ORDINA PER 2 DESC

Esempio

+-----+------------------------------+--------------------+--------------------
|    #|               wait_event_type|            duration|            % dbtime
+-----+------------------------------+--------------------+--------------------
|    1|                          Lock|            08:18:19|                6.07
|    2|                            IO|            06:16:01|                4.58
|    3|                       Timeout|            02:53:21|                2.11
|    4|                        LWLock|            00:58:12|                0.71
|    5|                        Client|            00:01:19|                0.02
|    6|                           IPC|            00:00:04|                   0
+-----+------------------------------+--------------------+--------------------

Durata delle attese, per processi di sistema e singole richieste.

ATTESE PER I PROCESSI DI SISTEMA

Richiesta

SELEZIONA 
  backend_type , datname , wait_event_type , wait_event , get_backend_type_waiting_duration( backend_type , wait_event_type , wait_event , pg_stat_history_begin+(current_hour_diff * intervallo '1 ora') , pg_stat_history_end+(current_hour_diff * intervallo '1 ora') ) come durata 
DA 
  activity_hist.archive_pg_stat_activity aa
DOVE 
  timepoint TRA pg_stat_history_begin+(current_hour_diff * intervallo '1 ora') E pg_stat_history_end+(current_hour_diff * intervallo '1 ora') E backend_type != 'client backend' E wait_event_type È NON NULL 
RAGGRUPPA PER backend_type , datname , wait_event_type , wait_event
ORDINA PER 5 DESC

Esempio

+-----+-----------------------------+----------+--------------------+----------------------+--------------------
|    #|                 backend_type|    dbname|     wait_event_type|            wait_event|            duration
+-----+-----------------------------+----------+--------------------+----------------------+--------------------
|    1| lanciatore di replica logica  |          |            Attività |   LogicalLauncherMain|            10:43:28
|    2|          lanciatore autovacuum|          |            Attività |        AutoVacuumMain|            10:42:49
|    3|                    walwriter   |          |            Attività |         WalWriterMain|            10:28:53
|    4|                 controllore    |          |            Attività |      CheckpointerMain|            10:23:50
|    5|            scrittore in background |          |            Attività |          BgWriterMain|            09:11:59
|    6|            scrittore in background |          |            Attività |     BgWriterHibernate|            01:37:46
|    7|              lavoratore parallelo |      tdb1|                  IO|          BufFileWrite|            00:02:35
|    8|              lavoratore parallelo |      tdb1|              LWLock|        buffer_mapping|            00:01:41
|    9|              lavoratore parallelo |      tdb1|                  IO|          DataFileRead|            00:01:22
|   10|              lavoratore parallelo |      tdb1|                  IO|           BufFileRead|            00:00:59
|   11|                    walwriter   |          |                  IO|              WALWrite|            00:00:57
|   12|              lavoratore parallelo |      tdb1|              LWLock|             buffer_io|            00:00:47
|   13|            lavoratore autovacuum |      tdb1|              LWLock|        buffer_mapping|            00:00:13
|   14|            scrittore in background |          |                  IO|         DataFileWrite|            00:00:12
|   15|                 controllore    |          |                  IO|         DataFileWrite|            00:00:11
|   16|                    walwriter   |          |              LWLock|          WALWriteLock|            00:00:09
|   17|                 controllore    |          |              LWLock|          WALWriteLock|            00:00:06
|   18|            scrittore in background |          |              LWLock|          WALWriteLock|            00:00:06
|   19|                    walwriter   |          |                  IO|          WALInitWrite|            00:00:02
|   20|            lavoratore autovacuum |      tdb1|              LWLock|          WALWriteLock|            00:00:02
|   21|                    walwriter   |          |                  IO|           WALInitSync|            00:00:02
|   22|            lavoratore autovacuum |      tdb1|                  IO|          DataFileRead|            00:00:01
|   23|                 controllore    |          |                  IO| ControlFileSyncUpdate|            00:00:01
|   24|            scrittore in background |          |                  IO|              WALWrite|            00:00:01
|   25|            scrittore in background |          |                  IO|         DataFileFlush|            00:00:01
|   26|                 controllore    |          |                  IO|         SLRUFlushSync|            00:00:01
|   27|            lavoratore autovacuum |      tdb1|                  IO|              WALWrite|            00:00:01
|   28|                 controllore    |          |                  IO|          DataFileSync|            00:00:01
+-----+-----------------------------+----------+--------------------+----------------------+--------------------

ATTESA PER SQL — attese per singole query per queryid

Richiesta

SELEZIONA 
queryid , datname , tipo_evento_attesa , evento_attesa , get_query_waiting_duration( queryid , tipo_evento_attesa , evento_attesa , pg_stat_history_begin+(current_hour_diff * interval '1 hour') , pg_stat_history_end+(current_hour_diff * interval '1 hour') ) come durata 
DA 
  activity_hist.archive_pg_stat_activity aa
DOVE 
  timepoint TRA pg_stat_history_begin+(current_hour_diff * interval '1 hour') E pg_stat_history_end+(current_hour_diff * interval '1 hour') E backend_type = 'client backend' E tipo_evento_attesa È NON NULL E queryid È NON NULL 
GROUP BY queryid , datname , tipo_evento_attesa , evento_attesa
ORDERINA PER 1 , 5 DESC 

Esempio

+-----+-------------------------+----------+--------------------+--------------------+--------------------+--------------------
|    #|                  queryid|    dbname|     wait_event_type|          wait_event|            waitings|               total
|     |                         |          |                    |                    |            duration|            duration
+-----+-------------------------+----------+--------------------+--------------------+--------------------+--------------------
|    1|     -8247416849404883188|      tdb1|              Client|          ClientRead|            00:00:02|
|    2|     -6572922443698419129|      tdb1|              Client|          ClientRead|            00:00:05|
|    3|     -6572922443698419129|      tdb1|                  IO|        DataFileRead|            00:00:01|
|    4|     -5917408132400665328|      tdb1|              Client|          ClientRead|            00:00:04|
|    5|     -4091009262735781873|      tdb1|              Client|          ClientRead|            00:00:03|
|    6|     -1473395109729441239|      tdb1|              Client|          ClientRead|            00:00:01|
|    7|        28942442626229688|      tdb1|                  IO|        BufFileWrite|            00:01:34|            00:46:06
|    8|        28942442626229688|      tdb1|              LWLock|      buffer_mapping|            00:01:05|            00:46:06
|    9|        28942442626229688|      tdb1|                  IO|        DataFileRead|            00:00:44|            00:46:06
|   10|        28942442626229688|      tdb1|                  IO|         BufFileRead|            00:00:37|            00:46:06
|   11|        28942442626229688|      tdb1|              LWLock|           buffer_io|            00:00:35|            00:46:06
|   12|        28942442626229688|      tdb1|              Client|          ClientRead|            00:00:05|            00:46:06
|   13|        28942442626229688|      tdb1|                 IPC| MessageQueueReceive|            00:00:03|            00:46:06
|   14|        28942442626229688|      tdb1|                 IPC|    BgWorkerShutdown|            00:00:01|            00:46:06
|   15|       389015618226997618|      tdb1|                Lock|       transactionid|            03:55:09|            04:14:15
|   16|       389015618226997618|      tdb1|                  IO|        DataFileRead|            03:23:09|            04:14:15
|   17|       389015618226997618|      tdb1|              LWLock|      buffer_mapping|            00:12:09|            04:14:15
|   18|       389015618226997618|      tdb1|              LWLock|           buffer_io|            00:10:18|            04:14:15
|   19|       389015618226997618|      tdb1|                Lock|               tuple|            00:00:35|            04:14:15
|   20|       389015618226997618|      tdb1|              LWLock|        WALWriteLock|            00:00:02|            04:14:15
|   21|       389015618226997618|      tdb1|                  IO|       DataFileWrite|            00:00:01|            04:14:15
|   22|       389015618226997618|      tdb1|              LWLock|        SyncScanLock|            00:00:01|            04:14:15
|   23|       389015618226997618|      tdb1|              Client|          ClientRead|            00:00:01|            04:14:15
|   24|       734234407411547467|      tdb1|              Client|          ClientRead|            00:00:11|
|   25|       734234407411547467|      tdb1|              LWLock|      buffer_mapping|            00:00:05|
|   26|       734234407411547467|      tdb1|                  IO|        DataFileRead|            00:00:02|
|   27|      1237430309438971376|      tdb1|              LWLock|      buffer_mapping|            00:02:18|            02:45:40
|   28|      1237430309438971376|      tdb1|                  IO|        DataFileRead|            00:00:27|            02:45:40
|   29|      1237430309438971376|      tdb1|              Client|          ClientRead|            00:00:02|            02:45:40
|   30|      2404820632950544954|      tdb1|              Client|          ClientRead|            00:00:01|
|   31|      2515308626622579467|      tdb1|              Client|          ClientRead|            00:00:02|
|   32|      4710212362688288619|      tdb1|              LWLock|      buffer_mapping|            00:03:08|            02:18:21
|   33|      4710212362688288619|      tdb1|                  IO|        DataFileRead|            00:00:22|            02:18:21
|   34|      4710212362688288619|      tdb1|              Client|          ClientRead|            00:00:06|            02:18:21
|   35|      4710212362688288619|      tdb1|              LWLock|           buffer_io|            00:00:02|            02:18:21
|   36|      9150846928388977274|      tdb1|                  IO|        DataFileRead|            00:01:19|
|   37|      9150846928388977274|      tdb1|              LWLock|      buffer_mapping|            00:00:34|
|   38|      9150846928388977274|      tdb1|              Client|          ClientRead|            00:00:10|
|   39|      9150846928388977274|      tdb1|              LWLock|           buffer_io|            00:00:01|
+-----+-------------------------+----------+--------------------+--------------------+--------------------+--------------------

STATISTICHE SQL CLIENT — TOP richieste

Le richieste per ottenere nuovamente sono banali e, per risparmiare spazio, non sono riportate.

Esempi

+------------------------------------------------------------------------------------
| CLIENT SQL ordinati per Tempo di Esecuzione
+--------------------+----------+----------+----------+----------+----------+--------------------
|        tempo trascorso|     chiamate|  % dbtime|     % CPU|      % IO|    dbname|             queryid
+--------------------+----------+----------+----------+----------+----------+--------------------
|            04:14:15|        19|       3.1|     10.83|     11.52|      tdb1|  389015618226997618
|            02:45:40|       746|      2.02|      4.23|      0.08|      tdb1| 1237430309438971376
|            02:18:21|       749|      1.69|      3.39|       0.1|      tdb1| 4710212362688288619
|            00:46:06|       375|      0.56|      0.94|      0.41|      tdb1|   28942442626229688
+--------------------+----------+----------+----------+----------+----------+--------------------
| CLIENT SQL ordinati per Tempo di CPU
+--------------------+----------+----------+----------+----------+----------+----------+--------------------
|            tempo cpu|     chiamate|  % dbtime|tempo_totale|     % CPU|      % IO|    dbname|             queryid
+--------------------+----------+----------+----------+----------+----------+----------+--------------------
|            02:59:49|        19|       3.1|  04:14:15|     10.83|     11.52|      tdb1|  389015618226997618
|            01:10:12|       746|      2.02|  02:45:40|      4.23|      0.08|      tdb1| 1237430309438971376
|            00:56:15|       749|      1.69|  02:18:21|      3.39|       0.1|      tdb1| 4710212362688288619
|            00:15:35|       375|      0.56|  00:46:06|      0.94|      0.41|      tdb1|   28942442626229688
+--------------------+----------+----------+----------+----------+----------+----------+--------------------
| CLIENT SQL ordinati per Tempo di Attesa I/O Utente
+--------------------+----------+----------+----------+----------+----------+----------+--------------------
|        tempo di attesa io|     chiamate|  % dbtime|tempo_totale|     % CPU|      % IO|    dbname|             queryid
+--------------------+----------+----------+----------+----------+----------+----------+--------------------
|            03:23:10|        19|       3.1|  04:14:15|     10.83|     11.52|      tdb1|  389015618226997618
|            00:02:54|       375|      0.56|  00:46:06|      0.94|      0.41|      tdb1|   28942442626229688
|            00:00:27|       746|      2.02|  02:45:40|      4.23|      0.08|      tdb1| 1237430309438971376
|            00:00:22|       749|      1.69|  02:18:21|      3.39|       0.1|      tdb1| 4710212362688288619
+--------------------+----------+----------+----------+----------+----------+----------+--------------------
| CLIENT SQL ordinati per Letture Buffer Condivisi
+--------------------+----------+----------+----------+----------+----------+----------+--------------------
|       letture buffer|     chiamate|  % dbtime|tempo_totale|     % CPU|      % IO|    dbname|             queryid
+--------------------+----------+----------+----------+----------+----------+----------+--------------------
|          1056388566|        19|       3.1|  04:14:15|     10.83|     11.52|      tdb1|  389015618226997618
|            11709251|       375|      0.56|  00:46:06|      0.94|      0.41|      tdb1|   28942442626229688
|             3439004|       746|      2.02|  02:45:40|      4.23|      0.08|      tdb1| 1237430309438971376
|             3373330|       749|      1.69|  02:18:21|      3.39|       0.1|      tdb1| 4710212362688288619
+--------------------+----------+----------+----------+----------+----------+----------+--------------------
| CLIENT SQL ordinati per Tempo di Letture Disco
+--------------------+----------+----------+----------+----------+----------+----------+--------------------
|           tempo di lettura|     chiamate|  % dbtime|tempo_totale|     % CPU|      % IO|    dbname|             queryid
+--------------------+----------+----------+----------+----------+----------+----------+--------------------
|            02:16:30|        19|       3.1|  04:14:15|     10.83|     11.52|      tdb1|  389015618226997618
|            00:04:50|       375|      0.56|  00:46:06|      0.94|      0.41|      tdb1|   28942442626229688
|            00:01:10|       749|      1.69|  02:18:21|      3.39|       0.1|      tdb1| 4710212362688288619
|            00:00:57|       746|      2.02|  02:45:40|      4.23|      0.08|      tdb1| 1237430309438971376
+--------------------+----------+----------+----------+----------+----------+----------+--------------------
| CLIENT SQL ordinati per Esecuzioni
+--------------------+----------+----------+----------+----------+----------+----------+--------------------
|               chiamate|      righe|  % dbtime|tempo_totale|     % CPU|      % IO|    dbname|             queryid
+--------------------+----------+----------+----------+----------+----------+----------+--------------------
|                 749|       749|      1.69|  02:18:21|      3.39|       0.1|      tdb1| 4710212362688288619
|                 746|       746|      2.02|  02:45:40|      4.23|      0.08|      tdb1| 1237430309438971376
|                 375|         0|      0.56|  00:46:06|      0.94|      0.41|      tdb1|   28942442626229688
|                  19|        19|       3.1|  04:14:15|     10.83|     11.52|      tdb1|  389015618226997618
+--------------------+----------+----------+----------+----------+----------+----------+--------------------

Risultato

Utilizzando le query fornite e la reportistica ottenuta, è possibile avere una visione più completa per analizzare e risolvere i problemi di degrado delle prestazioni, sia per singole query che per l'intero cluster.

Sviluppo

I prossimi piani di sviluppo sono:

  • Espandere la reportistica con una cronologia dei blocchi. Le query sono attualmente in fase di test e saranno presentate a breve.
  • Utilizzare l'estensione TimescaleDB per memorizzare la cronologia di pg_stat_activity e pg_locks.
  • Preparare una soluzione batch su GitHub per il deployment massivo sui database di produzione.

Continua...

Fonte: habr.com

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