🥇Salah satu kaedah untuk mendapatkan sejarah kunci dalam PostgreSQL

Sambungan artikel "Percubaan untuk mencipta analog ASH untuk PostgreSQL ".

Artikel itu akan meneliti dan menunjukkan, menggunakan pertanyaan dan contoh khusus, maklumat berguna yang boleh diperoleh menggunakan sejarah paparan pg_locks.

Amaran
Disebabkan kebaharuan topik dan tempoh ujian yang belum selesai, artikel mungkin mengandungi ralat. Kritikan dan komen amat dialu-alukan dan diharapkan.

Input data

Sejarah perwakilan pg_locks

mengunci_arkib

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 
);

Pada asasnya, jadual adalah serupa dengan jadual archive_pg_stat_activity, diterangkan dengan lebih terperinci di sini - pg_stat_statements + pg_stat_activity + loq_query = pg_ash? dan di sini - Percubaan untuk mencipta analog ASH untuk PostgreSQL.

Untuk mengisi lajur id pertanyaan fungsi digunakan

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;

Penjelasan: nilai lajur queryid dikemas kini dalam jadual history_locking, dan kemudian apabila partition baharu dicipta untuk jadual archive_locking, nilai akan disimpan dalam nilai sejarah.

Выходные данные

Maklumat am mengenai proses secara umum.

MENUNGGU LOCK BY LOCKTYPES

Permintaan

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

Contoh

| MENUNGGU LOCK BY LOCKTYPES
+--------------------+------------------------------ -----------------------
| jenis kunci| mod| tempoh masa
+--------------------+------------------------------ -----------------------
| transactionid| ShareLock| 19:39:26
| tupel| AccessExclusiveLock| 00:03:35
+--------------------+------------------------------ -----------------------

PENGAMBILAN KUNCI MENGIKUT JENIS KUNCI

Permintaan

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

Contoh

| PENGAMBILAN KUNCI MENGIKUT JENIS KUNCI
+--------------------+------------------------------ -----------------------
| jenis kunci| mod| tempoh masa
+--------------------+------------------------------ -----------------------
| hubungan| RowExclusiveLock| 51:11:10
| virtualxid| Kunci Eksklusif| 48:10:43
| transactionid| Kunci Eksklusif| 44:24:53
| hubungan| AccessShareLock| 20:06:13
| tupel| AccessExclusiveLock| 17:58:47
| tupel| Kunci Eksklusif| 01:40:41
| hubungan| ShareUpdateExclusiveLock| 00:26:41
| objek| RowExclusiveLock| 00:00:01
| transactionid| ShareLock| 00:00:01
| memanjangkan| Kunci Eksklusif| 00:00:01
+--------------------+------------------------------ -----------------------

Maklumat terperinci tentang permintaan queryid tertentu

MENUNGGU KUNCI OLEH LOCKTYPES OLEH QUERYID

Permintaan

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

Contoh

| MENUNGGU KUNCI OLEH LOCKTYPES OLEH QUERYID
+----------+----------+------------ --------+------ -----------------------+--------- ----------+------- ---------------------------+------------------- --
| pid| jenis kunci| mod| bermula| id pertanyaan| blocking_pids| tempoh masa
+----------+----------+------------ --------+------ -----------------------+--------- ----------+------- ---------------------------+------------------- --
| 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

MENGAMBIL KUNCI MENGIKUT JENIS KUNCI OLEH QUERYID

Permintaan

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

Contoh

| MENGAMBIL KUNCI MENGIKUT JENIS KUNCI OLEH QUERYID
+----------+----------+------------ --------+------ -----------------------+--------- ----------+------- ---------------------------+------------------- --
| pid| jenis kunci| mod| bermula| id pertanyaan| blocking_pids| tempoh masa
+----------+----------+------------ --------+------ -----------------------+--------- ----------+------- ---------------------------+------------------- --
| 11288| hubungan| RowExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34
| 11092| transactionid| Kunci Eksklusif| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:03:34
| 11288| hubungan| RowExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:00:10
| 11092| hubungan| RowExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:03:34
| 11092| virtualxid| Kunci Eksklusif| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:03:34
| 11288| virtualxid| Kunci Eksklusif| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34
| 11288| transactionid| Kunci Eksklusif| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34
| 11288| tupel| AccessExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34

Menggunakan sejarah kunci untuk menganalisis insiden prestasi.

Permintaan dengan queryid=389015618226997618 yang dilaksanakan oleh proses dengan pid=11288 sedang menunggu untuk menyekat bermula dari 2019-09-17 10:00:00 selama 3 minit.
Kunci itu dipegang oleh proses dengan pid=11092
Satu proses dengan pid=11092 melaksanakan permintaan dengan queryid=389015618226997618 bermula dari 2019-09-17 10:00:00 menahan kunci selama 3 minit.

Jumlah

Sekarang, saya harap, bahagian yang paling menarik dan berguna akan bermula - mengumpul statistik dan menganalisis kes mengenai sejarah menunggu dan menyekat.

Pada masa akan datang, saya ingin percaya, kita akan mendapat satu set beberapa nota (serupa dengan metalink Oracle).

Secara umum, atas sebab inilah metodologi yang digunakan disediakan kepada semua orang secepat mungkin.

Saya akan cuba menyiarkan projek di github dalam masa terdekat.

Sumber: www.habr.com

Salah satu kaedah untuk mendapatkan sejarah kunci dalam PostgreSQL

Input data

Sejarah perwakilan pg_locks

Выходные данные

MENUNGGU LOCK BY LOCKTYPES

PENGAMBILAN KUNCI MENGIKUT JENIS KUNCI

MENUNGGU KUNCI OLEH LOCKTYPES OLEH QUERYID

MENGAMBIL KUNCI MENGIKUT JENIS KUNCI OLEH QUERYID

Jumlah

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