🥇Viena no metodēm bloķēšanas vēstures iegūšanai programmā PostgreSQL

Raksta turpinājums "Mēģinājums izveidot PostgreSQL ASH analogu ".

Rakstā tiks apskatīts un, izmantojot īpašus vaicājumus un piemērus, tiks parādīts, kādu noderīgu informāciju var iegūt, izmantojot pg_locks skata vēsturi.

Brīdinājums.
Tēmas novitātes un nepabeigtā testēšanas perioda dēļ rakstā var būt kļūdas. Kritika un komentāri ir ļoti apsveicami un gaidīti.

Ievadiet datus

pg_locks attēlojuma vēsture

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 
);

Būtībā tabula ir līdzīga tabulai archive_pg_stat_activity, sīkāk aprakstīts šeit - pg_stat_statements + pg_stat_activity + loq_query = pg_ash? un šeit - Mēģinājums izveidot ASH analogu PostgreSQL.

Lai aizpildītu kolonnu queryid funkcija tiek izmantota

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;

Paskaidrojums: kolonnas queryid vērtība tiek atjaunināta tabulā history_locking, un tad, kad tabulai archive_locking tiek izveidots jauns nodalījums, vērtība tiks saglabāta vēsturiskajās vērtībās.

Izeja

Vispārīga informācija par procesiem kopumā.

GAIDA SLĒDZES PĒC LOCKTIPIEM

Pretenzija

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

Piemērs

| GAIDA SLĒDZES PĒC LOCKTIPIEM +------------+----------------------- ---------+ -------------------- | slēdzenes veids| režīms| ilgums +--------------------+--------------------------- --+--------------------- | transakciju| ShareLock| 19:39:26 | tuple| AccessExclusiveLock| 00:03:35 +-------------------+----------------------- -------+-----------

SLĒDŽU ŅEMŠANA PĒC LOKTIPIEM

Pretenzija

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

Piemērs

| SLĒDŽU ŅEMŠANA PĒC LOKTIPIEM +---------------------+------------------------ --------+-------------------- | slēdzenes veids| režīms| ilgums +--------------------+--------------------------- --+--------------------- | saistība| RowExclusiveLock| 51:11:10 | virtualxid| ExclusiveLock| 48:10:43 | transakciju| ExclusiveLock| 44:24:53 | saistība| AccessShareLock| 20:06:13 | tuple| AccessExclusiveLock| 17:58:47 | tuple| ExclusiveLock| 01:40:41 | saistība| ShareUpdateExclusiveLock| 00:26:41 | objekts| RowExclusiveLock| 00:00:01 | transakciju| ShareLock| 00:00:01 | pagarināt| ExclusiveLock| 00:00:01 +-------------------+----------------------- -------+-----------

Detalizēta informācija par konkrētiem vaicājuma ID pieprasījumiem

GAIDA SLĒDZES PĒC LOCKTYPES PĒC VAJADZĪBAS ID

Pretenzija

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

Piemērs

| GAIDA SLĒDZES PĒC LOKETIPIEM PĒC JAUTĀJUMA +-----------+----------+----- --------------- +----------------------------+--- ----------------- -+--------------------+----------- ---------- | pid| slēdzenes veids| režīms| sākās| queryid| blocking_pids| ilgums +----------+--------------------------+------------ ---------+-------------------------------+--------- -----------+---------------------+------------------ --- | 11288| transakciju| ShareLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34 | 11626| transakciju| ShareLock| 2019-09-17 10:00:21.380921| 389015618226997618| {12380}| 00:00:29 | 11626| transakciju| ShareLock| 2019-09-17 10:00:21.380921| 389015618226997618| {11092}| 00:03:25 | 11626| transakciju| ShareLock| 2019-09-17 10:00:21.380921| 389015618226997618| {12213}| 00:01:55 | 11626| transakciju| ShareLock| 2019-09-17 10:00:21.380921| 389015618226997618| {12751}| 00:00:01 | 11629| transakciju| ShareLock| 2019-09-17 10:00:24.331935| 389015618226997618| {11092}| 00:03:22 | 11629| transakciju| ShareLock| 2019-09-17 10:00:24.331935| 389015618226997618| {12007}| 00:00:01 | 12007| transakciju| ShareLock| 2019-09-17 10:05:03.327933| 389015618226997618| {11629}| 00:00:13 | 12007| transakciju| ShareLock| 2019-09-17 10:05:03.327933| 389015618226997618| {11092}| 00:01:10 | 12007| transakciju| ShareLock| 2019-09-17 10:05:03.327933| 389015618226997618| {11288}| 00:00:05 | 12213| transakciju| ShareLock| 2019-09-17 10:06:07.328019| 389015618226997618| {12007}| 00:00:10

SLĒDŽU ŅEMŠANA PĒC LOCKTIPIEM PĒC VAJADZĪJUMA

Pretenzija

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

Piemērs

| SLĒDZEŅU ŅEMŠANA PĒC LOKTIPIEM PĒC JAUTĀJUMA +-----------+-----------+------ --------------+ ----------------------------+---- ----------------+ --------------------+------------ --------- | pid| slēdzenes veids| režīms| sākās| queryid| blocking_pids| ilgums +----------+--------------------------+------------ ---------+-------------------------------+--------- -----------+---------------------+------------------ --- | 11288| saistība| RowExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34 | 11092| transakciju| ExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:03:34 | 11288| saistība| RowExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:00:10 | 11092| saistība| 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| transakciju| ExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34 | 11288| tuple| AccessExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34

Bloķēšanas vēstures izmantošana, lai analizētu veiktspējas incidentus.

Pieprasījums ar queryid=389015618226997618, ko izpildīja process ar pid=11288, gaidīja bloķēšanu, sākot no 2019-09-17 10:00:00 3 minūtes.
Bloķēšanu aizturēja process ar pid=11092
Process ar pid=11092, kas izpilda pieprasījumu ar queryid=389015618226997618, sākot no 2019-09-17 10:00:00, saglabāja bloķēšanu 3 minūtes.

Kopsavilkums

Tagad, es ceru, sāksies interesantākā un noderīgākā daļa - statistikas vākšana un gadījumu analīze par gaidīšanas un bloķēšanas vēsturi.

Es gribu ticēt, ka nākotnē mēs iegūsim dažu piezīmju komplektu (līdzīgi kā Oracle metalink).

Kopumā šī iemesla dēļ izmantotā metodika ir pieejama ikvienam pēc iespējas ātrāk.

Es mēģināšu tuvākajā laikā ievietot projektu github.

Avots: www.habr.com

Viena no metodēm bloķēšanas vēstures iegūšanai programmā PostgreSQL

Ievadiet datus

pg_locks attēlojuma vēsture

Izeja

GAIDA SLĒDZES PĒC LOCKTIPIEM

SLĒDŽU ŅEMŠANA PĒC LOKTIPIEM

GAIDA SLĒDZES PĒC LOCKTYPES PĒC VAJADZĪBAS ID

SLĒDŽU ŅEMŠANA PĒC LOCKTIPIEM PĒC VAJADZĪJUMA

Kopsavilkums

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