🥇Ien fan 'e metoaden foar it krijen fan slotskiednis yn PostgreSQL

Ferfolch fan it artikel "In besykjen om in ASH-analooch te meitsjen foar PostgreSQL ".

It artikel sil ûndersiikje en sjen litte, mei help fan spesifike fragen en foarbylden, hokker nuttige ynformaasje kin wurde krigen mei de skiednis fan 'e werjefte fan pg_locks.

Warskôging.
Fanwegen de nijichheid fan it ûnderwerp en de ûnfoltôge testperioade kin it artikel flaters befetsje. Krityk en opmerkings wurde tige wolkom en ferwachte.

Ynfier gegevens

Skiednis fan pg_locks fertsjintwurdiging

archive_locking

CREATE TABLE archive_locking 
(       timepoint timestamp without time zone ,
	locktype text ,
	relation oid ,
	mode text ,
	tid xid ,
	vtid text ,
	pid integer ,
	blocking_pids integer[] ,
	granted boolean ,
        queryid bigint 
);

Yn essinsje is de tafel fergelykber mei de tafel archive_pg_stat_activity, hjir yn mear detail beskreaun - pg_stat_statements + pg_stat_activity + loq_query = pg_ash? en hjir - In besykjen om in analoog fan ASH te meitsjen foar PostgreSQL.

Om in kolom te foljen queryid funksje wurdt brûkt

update_history_locking_by_queryid

--update_history_locking_by_queryid.sql
CREATE OR REPLACE FUNCTION update_history_locking_by_queryid() RETURNS boolean AS $$
DECLARE
  result boolean ;
  current_minute double precision ; 
  
  start_minute integer ;
  finish_minute integer ;
  
  start_period timestamp without time zone ;
  finish_period timestamp without time zone ;
  
  lock_rec record ; 
  endpoint_rec record ; 
  
  current_hour_diff double precision ;
BEGIN
  RAISE NOTICE '***update_history_locking_by_queryid';
  
  result = TRUE ;
  
  current_minute = extract ( minute from now() );

  SELECT * FROM endpoint WHERE is_need_monitoring
  INTO endpoint_rec ;
  
  current_hour_diff = endpoint_rec.hour_diff ;
  
  IF current_minute < 5 
  THEN
	RAISE NOTICE 'Current time is less than 5 minute.';
	
	start_period = date_trunc('hour',now()) + (current_hour_diff * interval '1 hour');
    finish_period = start_period - interval '5 minute' ;
  ELSE 
    finish_minute =  extract ( minute from now() ) / 5 ;
    start_minute =  finish_minute - 1 ;
  
    start_period = date_trunc('hour',now()) + interval '1 minute'*start_minute*5+(current_hour_diff * interval '1 hour');
    finish_period = date_trunc('hour',now()) + interval '1 minute'*finish_minute*5+(current_hour_diff * interval '1 hour') ;
    
  END IF ;  
  
  RAISE NOTICE 'start_period = %', start_period;
  RAISE NOTICE 'finish_period = %', finish_period;

	FOR lock_rec IN   
	WITH act_queryid AS
	 (
		SELECT 
				pid , 
				timepoint ,
				query_start AS started ,			
				MAX(timepoint) OVER (PARTITION BY pid ,	query_start   ) AS finished ,			
				queryid 
		FROM 
				activity_hist.history_pg_stat_activity 			
		WHERE 			
				timepoint BETWEEN start_period and 
								  finish_period
		GROUP BY 
				pid , 
				timepoint ,  
				query_start ,
				queryid 
	 ),
	 lock_pids AS
		(
			SELECT
				hl.pid , 
				hl.locktype  ,
				hl.mode ,
				hl.timepoint , 
				MIN ( timepoint ) OVER (PARTITION BY pid , locktype  ,mode ) as started 
			FROM 
				activity_hist.history_locking hl
			WHERE 
				hl.timepoint between start_period and 
								     finish_period
			GROUP BY 
				hl.pid , 
				hl.locktype  ,
				hl.mode ,
				hl.timepoint 
		)
	SELECT 
		lp.pid , 
		lp.locktype  ,
		lp.mode ,
		lp.timepoint ,     
		aq.queryid 
	FROM lock_pids 	lp LEFT OUTER JOIN act_queryid aq ON ( lp.pid = aq.pid AND lp.started BETWEEN aq.started AND aq.finished )
	WHERE aq.queryid IS NOT NULL 
	GROUP BY  
		lp.pid , 
		lp.locktype  ,
		lp.mode ,
		lp.timepoint , 
		aq.queryid
	LOOP
		UPDATE activity_hist.history_locking SET queryid = lock_rec.queryid 
		WHERE pid = lock_rec.pid AND locktype = lock_rec.locktype AND mode = lock_rec.mode AND timepoint = lock_rec.timepoint ;	
	END LOOP;    
  
  RETURN result ;
END
$$ LANGUAGE plpgsql;

Taljochting: de wearde fan 'e kolom queryid wurdt bywurke yn' e history_locking-tabel, en dan as der in nije dieling wurdt makke foar de archive_locking-tabel, wurdt de wearde opslein yn 'e histoaryske wearden.

Utfier

Algemiene ynformaasje oer prosessen yn it algemien.

WACHTEN OP SLOTTEN BY LOCKTYPES

Fersyk

WITH
t AS
(
	SELECT 
		locktype  ,
		mode ,
		count(*) as total 
	FROM 
		activity_hist.archive_locking
	WHERE 
		timepoint between pg_stat_history_begin+(current_hour_diff * interval '1 hour') AND pg_stat_history_end+(current_hour_diff * interval '1 hour') AND 
		NOT granted
	GROUP BY 
		locktype  ,
		mode  
)
SELECT 
	locktype  ,
	mode ,
	total * interval '1 second' as duration			
FROM t 		
ORDER BY 3 DESC

Foarbyld:

| WACHTEN OP SLOTTEN BY SLOTTYPEN +-----------+------------------------------------------+ ------------------- | slottype| modus| doer +---------------------+-------------------------------- - --+---------------------------- | transactionid| ShareLock| 19:39:26 | ryk| AccessExclusiveLock| 00:03:35 +--------------------+-------------------------------- - -------+----------

TAKEN FAN SLOTTEN BY LOCKTYPES

Fersyk

WITH
t AS
(
	SELECT 
		locktype  ,
		mode ,
		count(*) as total 
	FROM 
		activity_hist.archive_locking
	WHERE 
		timepoint between pg_stat_history_begin+(current_hour_diff * interval '1 hour') AND pg_stat_history_end+(current_hour_diff * interval '1 hour') AND 
		granted
	GROUP BY 
		locktype  ,
		mode  
)
SELECT 
	locktype  ,
	mode ,
	total * interval '1 second' as duration			
FROM t 		
ORDER BY 3 DESC

Foarbyld:

| TAKEN FAN SLOTTEN BY SLOTTYPEN +-------------------------+---------------------------------------- --------+------------------------ | slottype| modus| doer +---------------------+-------------------------------- - --+---------------------------- | relaasje| RowExclusiveLock| 51:11:10 | virtualxid| ExclusiveLock| 48:10:43 | transactionid| ExclusiveLock| 44:24:53 | relaasje| AccessShareLock| 20:06:13 | ryk| AccessExclusiveLock| 17:58:47 | ryk| ExclusiveLock| 01:40:41 | relaasje| ShareUpdateExclusiveLock| 00:26:41 | objekt| RowExclusiveLock| 00:00:01 | transactionid| ShareLock| 00:00:01 | útwreidzje | ExclusiveLock| 00:00:01 +--------------------+----------------------------- -------+----------

Detaillearre ynformaasje oer spesifike queryid-oanfragen

WACHTEN OP SLOTTEN BY LOCKTYPES BY QUERYID

Fersyk

WITH
lt AS
(
	SELECT
		pid , 
		locktype  ,
		mode ,
		timepoint , 
		queryid , 
		blocking_pids ,
                MIN ( timepoint ) OVER (PARTITION BY pid , locktype  ,mode ) as started  
	FROM 
		activity_hist.archive_locking
	WHERE 
		timepoint between pg_stat_history_begin+(current_hour_diff * interval '1 hour') AND 
			                  pg_stat_history_end+(current_hour_diff * interval '1 hour') AND 
		NOT granted AND
	       queryid IS NOT NULL 
	GROUP BY 
	        pid , 
		locktype  ,
		mode ,
		timepoint ,
		queryid ,
		blocking_pids 
)
SELECT 
        lt.pid , 
	lt.locktype  ,
	lt.mode ,			
        lt.started ,
	lt.queryid  ,
	lt.blocking_pids ,
	COUNT(*)  * interval '1 second'	 as duration		
FROM lt 	
GROUP BY 
	lt.pid , 
        lt.locktype  ,
	lt.mode ,			
        lt.started ,
        lt.queryid ,
	lt.blocking_pids 
ORDER BY 4

Foarbyld:

| WACHTEN OP SLOTTEN FAN SLOTTYPEN FAN QUERYID +----------------------------- +-----------------------------+------------------- -+---------------------+------------------- --------- | pyk| slottype| modus| begûn| queryid| blocking_pids| doer +---------------------- ----------+-------------------------------------+ ---------------------------------- --- | 11288| transactionid| ShareLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34 | 11626| transactionid| ShareLock| 2019-09-17 10:00:21.380921| 389015618226997618| {12380}| 00:00:29 | 11626| transactionid| ShareLock| 2019-09-17 10:00:21.380921| 389015618226997618| {11092}| 00:03:25 | 11626| transactionid| ShareLock| 2019-09-17 10:00:21.380921| 389015618226997618| {12213}| 00:01:55 | 11626| transactionid| ShareLock| 2019-09-17 10:00:21.380921| 389015618226997618| {12751}| 00:00:01 | 11629| transactionid| ShareLock| 2019-09-17 10:00:24.331935| 389015618226997618| {11092}| 00:03:22 | 11629| transactionid| ShareLock| 2019-09-17 10:00:24.331935| 389015618226997618| {12007}| 00:00:01 | 12007| transactionid| ShareLock| 2019-09-17 10:05:03.327933| 389015618226997618| {11629}| 00:00:13 | 12007| transactionid| ShareLock| 2019-09-17 10:05:03.327933| 389015618226997618| {11092}| 00:01:10 | 12007| transactionid| ShareLock| 2019-09-17 10:05:03.327933| 389015618226997618| {11288}| 00:00:05 | 12213| transactionid| ShareLock| 2019-09-17 10:06:07.328019| 389015618226997618| {12007}| 00:00:10

SLOTTEN NEMEN FAN LOCKTYPES BY QUERYID

Fersyk

WITH
lt AS
(
	SELECT
		pid , 
		locktype  ,
		mode ,
		timepoint , 
		queryid , 
		blocking_pids ,
                MIN ( timepoint ) OVER (PARTITION BY pid , locktype  ,mode ) as started  
	FROM 
		activity_hist.archive_locking
	WHERE 
		timepoint between pg_stat_history_begin+(current_hour_diff * interval '1 hour') AND 
			                  pg_stat_history_end+(current_hour_diff * interval '1 hour') AND 
		granted AND
		queryid IS NOT NULL 
	GROUP BY 
	        pid , 
		locktype  ,
		mode ,
		timepoint ,
		queryid ,
		blocking_pids 
)
SELECT 
        lt.pid , 
	lt.locktype  ,
	lt.mode ,			
        lt.started ,
	lt.queryid  ,
	lt.blocking_pids ,
	COUNT(*)  * interval '1 second'	 as duration			
FROM lt 	
GROUP BY 
	lt.pid , 
	lt.locktype  ,
	lt.mode ,			
        lt.started ,
	lt.queryid ,
	lt.blocking_pids 
ORDER BY 4

Foarbyld:

| SLOTTEN NEMEN FAN LOCKTYPES BY QUERYID +-----+---------------------------- ----------------------------+---------------------------+ --------------------+---------------------------- | pyk| slottype| modus| begûn| queryid| blocking_pids| doer +---------------------- ----------------------------- ------------------------------- - | 11288| relaasje| RowExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34 | 11092| transactionid| ExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:03:34 | 11288| relaasje| RowExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:00:10 | 11092| relaasje| RowExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:03:34 | 11092| virtualxid| ExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:03:34 | 11288| virtualxid| ExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34 | 11288| transactionid| ExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34 | 11288| ryk| AccessExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34

Gebrûk fan slotskiednis om prestaasjesynsidinten te analysearjen.

In fersyk mei queryid=389015618226997618 útfierd troch in proses mei pid=11288 wachte op blokkearjen fanôf 2019-09-17 10:00:00 foar 3 minuten.
It slot waard holden troch in proses mei pid = 11092
In proses mei pid=11092 it útfieren fan in fersyk mei queryid=389015618226997618 begjinnend fan 2019-09-17 10:00:00 hold it slot foar 3 minuten.

It resultaat

No, ik hoopje, sil it meast nijsgjirrige en brûkbere diel begjinne - statistiken sammelje en gefallen analysearje oer de skiednis fan wachtsjen en blokkearjen.

Yn 'e takomst, wol ik leauwe, sille wy in set fan guon notysjes krije (lykas Oracle's metalink).

Yn 't algemien is it om dizze reden dat de brûkte metodyk sa gau mooglik foar elkenien beskikber steld wurdt.

Ik sil besykje it projekt yn 'e heine takomst op github te pleatsen.

Boarne: www.habr.com

Ien fan 'e metoaden foar it krijen fan slotskiednis yn PostgreSQL

Ynfier gegevens

Skiednis fan pg_locks fertsjintwurdiging

Utfier

WACHTEN OP SLOTTEN BY LOCKTYPES

TAKEN FAN SLOTTEN BY LOCKTYPES

WACHTEN OP SLOTTEN BY LOCKTYPES BY QUERYID

SLOTTEN NEMEN FAN LOCKTYPES BY QUERYID

It resultaat

Add a comment cancel reply