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Ein af aðferðunum til að fá læsingarsögu í PostgreSQL

Framhald greinarinnar “Tilraun til að búa til ASH hliðstæðu fyrir PostgreSQL ".

Greinin mun skoða og sýna, með því að nota sérstakar fyrirspurnir og dæmi, hvaða gagnlegar upplýsingar er hægt að fá með því að nota sögu pg_locks útsýnisins.

Viðvörun
Vegna nýjungarinnar í efninu og ólokið prófunartímabils getur greinin innihaldið villur. Gagnrýni og athugasemdir eru mjög vel þegnar og búist við.

Inntaksgögn

Saga pg_locks framsetningar

skjalasafnslæsing

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 
);

Í meginatriðum er borðið svipað og borðið archive_pg_stat_activity, nánar lýst hér - pg_stat_statements + pg_stat_activity + loq_query = pg_ash? og hér - Tilraun til að búa til hliðstæðu ASH fyrir PostgreSQL.

Til að fylla dálk queryid aðgerð er notuð

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;

Útskýring: gildi queryid dálksins er uppfært í history_locking töflunni og síðan þegar ný skipting er búin til fyrir archive_locking töfluna verður gildið geymt í sögulegu gildunum.

Framleiðsla

Almennar upplýsingar um ferla almennt.

BÍÐA EFTIR LÁSUM MEÐ LÁSTYPUM

Beiðni

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

Dæmi

| BÍÐA EFTIR LÁSUM MEÐ LÁSTYPUM +------+------------------------------------------+ ------------------ | locktype| háttur| lengd +---------------------+-------------------------------- - --+---------------------------- | viðskiptanúmer| ShareLock| 19:39:26 | tuple| AccessExclusiveLock| 00:03:35 +--------------------+-------------------------------- - -------+----------

TÖKUN LÁSUM MEÐ LÁSTYPUM

Beiðni

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

Dæmi

| LÁSATEKNINGAR MEÐ LÁSTYPUM +-------------------------+------------------------------ ----+------------------------- | locktype| háttur| lengd +---------------------+-------------------------------- - --+---------------------------- | samband| RowExclusiveLock| 51:11:10 | virtualxid| ExclusiveLock| 48:10:43 | viðskiptanúmer| ExclusiveLock| 44:24:53 | samband| AccessShareLock| 20:06:13 | tuple| AccessExclusiveLock| 17:58:47 | tuple| ExclusiveLock| 01:40:41 | samband| ShareUpdateExclusiveLock| 00:26:41 | mótmæla| RowExclusiveLock| 00:00:01 | viðskiptanúmer| ShareLock| 00:00:01 | lengja | ExclusiveLock| 00:00:01 +------------------------+----------------------------- - -------+----------

Ítarlegar upplýsingar um sérstakar beiðnir um queryid

BÍÐUR EFTIR LÁSINGUM EFTIR LOCKTYPES EFTIR QUERYID

Beiðni

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

Dæmi

| BÍÐA EFTIR LÁSINGUM MEÐ LOCKTYPES BY QUERYID +------------------------------------------- +--------------------------------+--- ------------------ --+--------------------+---------------- ---------- | pid| locktype| háttur| byrjaði| queryid| blocking_pids| lengd +------------------------ ---------------------------------------------+--------- ------------------------------+ --- | 11288| viðskiptanúmer| ShareLock| 2019 09:17:10| 00| {00.302936}| 389015618226997618:11092:00 | 03| viðskiptanúmer| ShareLock| 34 11626:2019:09| 17| {10}| 00:21.380921:389015618226997618 | 12380| viðskiptanúmer| ShareLock| 00 00:29:11626| 2019| {09}| 17:10:00 | 21.380921| viðskiptanúmer| ShareLock| 389015618226997618 11092:00:03| 25| {11626}| 2019:09:17 | 10| viðskiptanúmer| ShareLock| 00 21.380921:389015618226997618:12213| 00| {01}| 55:11626:2019 | 09| viðskiptanúmer| ShareLock| 17 10:00:21.380921| 389015618226997618| {12751}| 00:00:01 | 11629| viðskiptanúmer| ShareLock| 2019 09:17:10| 00| {24.331935}| 389015618226997618:11092:00 | 03| viðskiptanúmer| ShareLock| 22 11629:2019:09| 17| {10}| 00:24.331935:389015618226997618 | 12007| viðskiptanúmer| ShareLock| 00 00:01:12007| 2019| {09}| 17:10:05 | 03.327933| viðskiptanúmer| ShareLock| 389015618226997618 11629:00:00| 13| {12007}| 2019:09:17 | 10| viðskiptanúmer| ShareLock| 05 03.327933:389015618226997618:11092| 00| {01}| 10:12007:2019

AÐ TAKA LÁSA MEÐ LOCKTYPES MEÐ QUERYID

Beiðni

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

Dæmi

| LÁSINGAR MEÐ LOCKTYPES MEÐ QUERYID +----------------------------------+ ----------------------------+--------------------+ --------------------+---------------------------- | pid| locktype| háttur| byrjaði| queryid| blocking_pids| lengd +------------------------ ---------------------------------------------+--------- ------------------------------+ --- | 11288| samband| RowExclusiveLock| 2019 09:17:10| 00| {00.302936}| 389015618226997618:11092:00 | 03| viðskiptanúmer| ExclusiveLock| 34 11092:2019:09| 17| {}| 10:00:00.302936 | 389015618226997618| samband| RowExclusiveLock| 00 03:34:11288| 2019| {}| 09:17:10 | 00| samband| RowExclusiveLock| 00.302936 389015618226997618:00:00| 10| {}| 11092:2019:09 | 17| virtualxid| ExclusiveLock| 10 00:00.302936:389015618226997618| 00| {}| 03:34:11092 | 2019| virtualxid| ExclusiveLock| 09 17:10:00| 00.302936| {389015618226997618}| 00:03:34 | 11288| viðskiptanúmer| ExclusiveLock| 2019 09:17:10| 00| {00.302936}| 389015618226997618:11092:00 | 03| tuple| AccessExclusiveLock| 34 11288:2019:09| 17| {10}| 00:00.302936:389015618226997618

Notkun læsingasögu til að greina frammistöðuatvik.

  1. Beiðni með queryid=389015618226997618 framkvæmd með ferli með pid=11288 beið eftir lokun frá og með 2019-09-17 10:00:00 í 3 mínútur.
  2. Læsingunni var haldið með ferli með pid=11092
  3. Ferli þar sem pid=11092 framkvæmir beiðni með queryid=389015618226997618 frá og með 2019-09-17 10:00:00 hélt læsingunni í 3 mínútur.

Samtals

Nú, vona ég, byrjar áhugaverðasti og gagnlegasti hlutinn - að safna tölfræði og greina tilvik um sögu bið og lokunar.

Í framtíðinni, ég vil trúa, munum við fá sett af nokkrum athugasemdum (svipað og Oracle's metallink).

Almennt séð er það af þessum sökum sem aðferðafræðin sem notuð er er gerð aðgengileg öllum eins fljótt og auðið er.

Ég mun reyna að birta verkefnið á github á næstunni.

Heimild: www.habr.com

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