🥇Isa sa mga pamamaraan para sa pagkuha ng kasaysayan ng lock sa PostgreSQL

Pagpapatuloy ng artikulo "Isang pagtatangka na lumikha ng isang ASH analogue para sa PostgreSQL ".

Susuriin at ipapakita ng artikulo, gamit ang mga partikular na query at halimbawa, kung anong kapaki-pakinabang na impormasyon ang makukuha gamit ang kasaysayan ng view ng pg_locks.

Babala
Dahil sa pagiging bago ng paksa at ang hindi natapos na panahon ng pagsubok, ang artikulo ay maaaring maglaman ng mga error. Ang mga kritisismo at komento ay lubos na tinatanggap at inaasahan.

Input ang data

Kasaysayan ng representasyon ng pg_locks

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 
);

Sa pangkalahatan, ang talahanayan ay katulad ng talahanayan archive_pg_stat_activity, inilarawan nang mas detalyado dito - pg_stat_statements + pg_stat_activity + loq_query = pg_ash? at dito - Isang pagtatangka na lumikha ng analogue ng ASH para sa PostgreSQL.

Upang punan ang isang column queryid ginagamit ang function

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;

Paliwanag: ang halaga ng column ng queryid ay ina-update sa history_locking table, at pagkatapos ay kapag ang isang bagong partition ay ginawa para sa archive_locking table, ang halaga ay maiimbak sa mga makasaysayang halaga.

Paglabas

Pangkalahatang impormasyon sa mga proseso sa pangkalahatan.

NAGHIHINTAY NG MGA LOCK BY LOCKTYPES

Humiling

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

Halimbawa

| NAGHIHINTAY NG MGA LOCK BY LOCKTYPES +-----------+---------- ---------+ ------------------- | locktype| mode| tagal +--------------------+--------------------------------------- - ------------------------ | transactionid| ShareLock| 19:39:26 | tuple| AccessExclusiveLock| 00:03:35 +----------------------+---------------------- - -------+----------

PAGKUHA NG MGA LOCK NG LOCKTYPES

Humiling

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

Halimbawa

| PAGKUHA NG MGA LOCKS NG LOCKTYPES +---------------------+----------------------- -----------------------+-------------------- | locktype| mode| tagal +--------------------+--------------------------------------- - ------------------------ | relasyon| RowExclusiveLock| 51:11:10 | virtualxid| ExclusiveLock| 48:10:43 | transactionid| ExclusiveLock| 44:24:53 | relasyon| AccessShareLock| 20:06:13 | tuple| AccessExclusiveLock| 17:58:47 | tuple| ExclusiveLock| 01:40:41 | relasyon| ShareUpdateExclusiveLock| 00:26:41 | bagay| RowExclusiveLock| 00:00:01 | transactionid| ShareLock| 00:00:01 | pahabain| ExclusiveLock| 00:00:01 +--------------------+---------------------- - -------+----------

Detalyadong impormasyon sa mga partikular na kahilingan sa queryid

NAGHIHINTAY NG MGA LOCK BY LOCKTYPES BY QUERYID

Humiling

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

Halimbawa

| NAGHIHINTAY NG MGA LOCK BY LOCKTYPES BY QUERYID +----------+----------+----- --------------- +----------------------------+-------------------- -----------------------+----------- --------- | pid| locktype| mode| nagsimula| queryid| blocking_pids| tagal +----------+------------------------+----------- -----------------------+--------------------------------+--------- --------------------------+---------------------+----------------- --- | 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

PAGGAMIT NG MGA LOCKTYPE NG QUERYID

Humiling

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

Halimbawa

| PAGKUHA NG MGA LOCKTYPE NG LOCKTYPES NG QUERYID +----------+-----------+------ --------------+ ------------------------------------ + ---------------------------------- --------- | pid| locktype| mode| nagsimula| queryid| blocking_pids| tagal +----------+------------------------+----------- -----------------------+--------------------------------+--------- --------------------------+---------------------+----------------- --- | 11288| relasyon| 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| relasyon| RowExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:00:10 | 11092| relasyon| 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| tuple| AccessExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34

Paggamit ng kasaysayan ng lock upang pag-aralan ang mga insidente ng pagganap.

Ang isang kahilingan na may queryid=389015618226997618 na isinagawa ng isang proseso na may pid=11288 ay naghihintay ng pagharang simula 2019-09-17 10:00:00 sa loob ng 3 minuto.
Ang lock ay hawak ng isang proseso na may pid=11092
Isang proseso na may pid=11092 na nagpapatupad ng isang kahilingan na may queryid=389015618226997618 simula 2019-09-17 10:00:00 hinawakan ang lock sa loob ng 3 minuto.

Kabuuan

Ngayon, umaasa ako, magsisimula ang pinakakawili-wili at kapaki-pakinabang na bahagi - pagkolekta ng mga istatistika at pagsusuri ng mga kaso sa kasaysayan ng mga paghihintay at pagharang.

Sa hinaharap, gusto kong maniwala, makakakuha tayo ng isang set ng ilang mga tala (katulad ng metalink ng Oracle).

Sa pangkalahatan, ito ay para sa kadahilanang ito na ang pamamaraang ginamit ay ginawang magagamit sa lahat sa lalong madaling panahon.

Susubukan kong i-post ang proyekto sa github sa malapit na hinaharap.

Pinagmulan: www.habr.com

Isa sa mga pamamaraan para sa pagkuha ng kasaysayan ng lock sa PostgreSQL

Input ang data

Kasaysayan ng representasyon ng pg_locks

Paglabas

NAGHIHINTAY NG MGA LOCK BY LOCKTYPES

PAGKUHA NG MGA LOCK NG LOCKTYPES

NAGHIHINTAY NG MGA LOCK BY LOCKTYPES BY QUERYID

PAGGAMIT NG MGA LOCKTYPE NG QUERYID

Kabuuan

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