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Üks meetod PostgreSQL-i lukustamise ajaloo saamiseks

Artikli jätk «Katse luua ASH-i analoog PostgreSQL-ile «.

Artiklis käsitletakse ja tuuakse konkreetsed päringud ja näited, et näidata, millist kasulikku teavet saab pg_locks ajaloo abil saada.

Hoiatus.
Seoses teema uudsetega ja katseperioodi täiendamisega võib artikkel sisaldada vigu. Kritika ja märkused on teretulnud ja oodatud.

Sisendandmed

pg_locks vaatamise ajalugu

archive_locking

Loo tabel 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 
);

Sisuliselt on tabel sarnane tabeliga archive_pg_stat_activity, nagu on siin üksikasjalikult kirjeldatud — pg_stat_statements + pg_stat_activity + loq_query = pg_ash? ja siin — Katse luua ASH-i analoog PostgreSQL-ile.

Veerust queryid täitmiseks kasutatakse funktsiooni

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;

Selgitus: veerg queryid väärtus uuendatakse tabelis history_locking ja seejärel, kui luuakse uus jaotis tabelile archive_locking, salvestatakse väärtus ajalukku.

Väljund

Üldinfo protsesside kohta.

LOCKTIPID JA LOCKTÜÜPID

Päring

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

Näide

| LOCKTIPID JA LOCKTÜÜPID
+--------------------+------------------------------+--------------------
|            locktype|                          mode|            duration
+--------------------+------------------------------+--------------------
|       transactionid|                     ShareLock|            19:39:26
|               tuple|           AccessExclusiveLock|            00:03:35
+--------------------+------------------------------+--------------------

LOCKTIPID JA LOCKTÜÜPID

Päring

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

Näide

| LUKUSTE OMANDMINE LUKUTÜÜPIDE JÄRGE
+--------------------+------------------------------+--------------------
|            lukutüüp|                          režiim|            kestus
+--------------------+------------------------------+--------------------
|            suhe|              RowExclusiveLock|            51:11:10
|          virtuaalid|                 ExclusiveLock|            48:10:43
|       tehingu ID|                 ExclusiveLock|            44:24:53
|            suhe|               AccessShareLock|            20:06:13
|               tupel|           AccessExclusiveLock|            17:58:47
|               tupel|                 ExclusiveLock|            01:40:41
|            suhe|      ShareUpdateExclusiveLock|            00:26:41
|              objekt|              RowExclusiveLock|            00:00:01
|       tehingu ID|                     ShareLock|            00:00:01
|              laiend|                 ExclusiveLock|            00:00:01
+--------------------+------------------------------+--------------------

Detailne teave konkreetsete queryid päringute kohta

OOTAMINE LUKUSTE JÄRGE LUKUTÜÜPIDE KOHTA QUERYID PÄRINGUTE KOHTA

Päring

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

Näide

| OOTAMIS TÕKKEDE KINNIPEETUD TÜÜBID KÜSIMUSTE ID ALUSEL
+----------+-------------------------+--------------------+------------------------------+--------------------+--------------------+--------------------
|       pid|                 lukutüüp|                režiim|                       algus|             küsimuse_id|       blokeerimise_pid|            kestus
+----------+-------------------------+--------------------+------------------------------+--------------------+--------------------+--------------------
|     11288|            tehingu_id|           ShareLock|    2019-09-17 10:00:00.302936|  389015618226997618|             {11092}|            00:03:34
|     11626|            tehingu_id|           ShareLock|    2019-09-17 10:00:21.380921|  389015618226997618|             {12380}|            00:00:29
|     11626|            tehingu_id|           ShareLock|    2019-09-17 10:00:21.380921|  389015618226997618|             {11092}|            00:03:25
|     11626|            tehingu_id|           ShareLock|    2019-09-17 10:00:21.380921|  389015618226997618|             {12213}|            00:01:55
|     11626|            tehingu_id|           ShareLock|    2019-09-17 10:00:21.380921|  389015618226997618|             {12751}|            00:00:01
|     11629|            tehingu_id|           ShareLock|    2019-09-17 10:00:24.331935|  389015618226997618|             {11092}|            00:03:22
|     11629|            tehingu_id|           ShareLock|    2019-09-17 10:00:24.331935|  389015618226997618|             {12007}|            00:00:01
|     12007|            tehingu_id|           ShareLock|    2019-09-17 10:05:03.327933|  389015618226997618|             {11629}|            00:00:13
|     12007|            tehingu_id|           ShareLock|    2019-09-17 10:05:03.327933|  389015618226997618|             {11092}|            00:01:10
|     12007|            tehingu_id|           ShareLock|    2019-09-17 10:05:03.327933|  389015618226997618|             {11288}|            00:00:05
|     12213|            tehingu_id|           ShareLock|    2019-09-17 10:06:07.328019|  389015618226997618|             {12007}|            00:00:10

LOCKITÜÜDID LOCKTÜÜPIDE KOHTA KÜSIMUSE ID JÄRGI

Päring

KAUGEND
lt AS
(
	VALI
		pid , 
		locktype  ,
		mode ,
		timepoint , 
		queryid , 
		blocking_pids ,
                MIN ( timepoint ) OVER (PARTITION BY pid , locktype  ,mode ) as started  
	FROM 
		activity_hist.archive_locking
	KUS
		timepoint on pg_stat_history_begin+(current_hour_diff * interval '1 hour') JA 
			                  pg_stat_history_end+(current_hour_diff * interval '1 hour') JA 
		granted JA
		queryid EI OLE NULL 
	GRUPPEERI 
	        pid , 
		locktype  ,
		mode ,
		timepoint ,
		queryid ,
		blocking_pids 
)
VALI 
        lt.pid , 
	lt.locktype  ,
	lt.mode ,			
        lt.started ,
	lt.queryid  ,
	lt.blocking_pids ,
	COUNT(*)  * interval '1 second'	 as duration			
FROM lt 	
GRUPPEERI 
	lt.pid , 
	lt.locktype  ,
	lt.mode ,			
        lt.started ,
	lt.queryid ,
	lt.blocking_pids 
JÄRJE NING 4

Näide

| LUKUSTE VÕTMINE LOCKTÜÜPIDEGA KÜSIMUS-ID MÜÜDID
+----------+-------------------------+--------------------+------------------------------+--------------------+--------------------+--------------------
|       pid|                 locktype|                mode|                       started|             queryid|       blocking_pids|            duration
+----------+-------------------------+--------------------+------------------------------+--------------------+--------------------+--------------------
|     11288|                 relation|    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|                 relation|    RowExclusiveLock|    2019-09-17 10:00:00.302936|  389015618226997618|                  {}|            00:00:10
|     11092|                 relation|    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

Blokeerimise ajaloo kasutamine jõudluse probleemide analüüsimisel.

  1. Küsimus, mille queryid on 389015618226997618, ootas protsessiga, mille pid on 11288, lukustamist alates 2019-09-17 10:00:00 kolme minuti jooksul.
  2. Lukustust hoidis protsess, mille pid on 11092.
  3. Protsess, mille pid on 11092, täites päringut queryid 389015618226997618 alates 2019-09-17 10:00:00, hoidis lukustust kolme minuti jooksul.

Kokkuvõte

Nüüd, loodan, et algab midagi tõeliselt huvitavat ja kasulikku - statistika kogumine ja juhtumite analüüs oote- ja lukustamise ajaloost.

Tulevikus, loodan, et õnnestub luua teatud määral note (analoog Oraakli metallinkidele).

Hästi, just seetõttu esitatakse kasutatav meetod maksimaalselt kiiresti ühiste teadmiste jaoks.

Käesoleval ajal püüan projekti varsti githubi üles laadida.

Allikas: habr.com

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