Nastavak članka “
Članak će ispitati i pokazati, koristeći specifične upite i primjere, koje se korisne informacije mogu dobiti korištenjem historije prikaza pg_locks.
Upozorenje
Zbog novine teme i nezavršenog perioda testiranja, članak može sadržavati greške. Kritike i komentari su dobrodošli i očekivani.
Ulazni podaci
Istorija pg_locks reprezentacije
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
);
U suštini, tabela je slična tabeli archive_pg_stat_activity, detaljnije opisan ovdje -
Za popunjavanje kolone queryid koristi se funkcija
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;
Objašnjenje: vrijednost stupca queryid se ažurira u tablici history_locking, a zatim kada se kreira nova particija za tablicu archive_locking, vrijednost će biti pohranjena u povijesnim vrijednostima.
Izlaz
Opće informacije o procesima općenito.
ČEKA SE BRAVA PO VRSTAMA BRAVA
Zahtjev
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
Primjer:
| ČEKA BRAVA PO VRSTAMA BRAVA +----------+----------------------- --------+ ------------------- | locktype| mod| trajanje +--------------------+--------------------- - --+------------------- | transakcija| ShareLock| 19:39:26 | tuple| AccessExclusiveLock| 00:03:35 +-------------------+-------------------------------- - -------+---------
UZIMANJE BRAVA PO VRSTAMA BRAVA
Zahtjev
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
Primjer:
| UZIMANJE BRAVA PO VRSTAMA BRAVA +-------------------+----------------------- --------+------------------ | locktype| mod| trajanje +--------------------+--------------------- - --+------------------- | odnos| RowExclusiveLock| 51:11:10 | virtualxid| ExclusiveLock| 48:10:43 | transakcija| ExclusiveLock| 44:24:53 | odnos| AccessShareLock| 20:06:13 | tuple| AccessExclusiveLock| 17:58:47 | tuple| ExclusiveLock| 01:40:41 | odnos| ShareUpdateExclusiveLock| 00:26:41 | objekt| RowExclusiveLock| 00:00:01 | transakcija| ShareLock| 00:00:01 | proširiti| ExclusiveLock| 00:00:01 +-------------------+-------------------------------- - -------+---------
Detaljne informacije o specifičnim queryid zahtjevima
ČEKA SE ZAKLJUČAVANJA PO VRSTAMA ZAKLJUČAVANJA PO QUERYID-u
Zahtjev
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
Primjer:
| ČEKA BRAVA PO VRSTAMA BRAVA PREMA QUERYID-u +----------+----------+----- --------------- +----------------------------+--- ----------------- -+--------------------+----------- --------- | pid| locktype| mod| započeo| queryid| blocking_pids| trajanje +----------+-------------------------+---------- ---------+------------------------------+-------- -----------+--------------------+---------------- --- | 11288| transakcija| ShareLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34 | 11626| transakcija| ShareLock| 2019-09-17 10:00:21.380921| 389015618226997618| {12380}| 00:00:29 | 11626| transakcija| ShareLock| 2019-09-17 10:00:21.380921| 389015618226997618| {11092}| 00:03:25 | 11626| transakcija| ShareLock| 2019-09-17 10:00:21.380921| 389015618226997618| {12213}| 00:01:55 | 11626| transakcija| ShareLock| 2019-09-17 10:00:21.380921| 389015618226997618| {12751}| 00:00:01 | 11629| transakcija| ShareLock| 2019-09-17 10:00:24.331935| 389015618226997618| {11092}| 00:03:22 | 11629| transakcija| ShareLock| 2019-09-17 10:00:24.331935| 389015618226997618| {12007}| 00:00:01 | 12007| transakcija| ShareLock| 2019-09-17 10:05:03.327933| 389015618226997618| {11629}| 00:00:13 | 12007| transakcija| ShareLock| 2019-09-17 10:05:03.327933| 389015618226997618| {11092}| 00:01:10 | 12007| transakcija| ShareLock| 2019-09-17 10:05:03.327933| 389015618226997618| {11288}| 00:00:05 | 12213| transakcija| ShareLock| 2019-09-17 10:06:07.328019| 389015618226997618| {12007}| 00:00:10
PREUZIMANJE BRAVA PO VRSTAMA BRAVA PO QUERYID-u
Zahtjev
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
Primjer:
| UZIMANJE BRAVA PO VRSTAMA BRAVA PREMA QUERYID-u +----------+----------+------ --------------+ ----------------------------+---- ----------------+ --------------------+----------- -------- | pid| locktype| mod| započeo| queryid| blocking_pids| trajanje +----------+-------------------------+---------- ---------+------------------------------+-------- -----------+--------------------+---------------- --- | 11288| odnos| RowExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34 | 11092| transakcija| ExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:03:34 | 11288| odnos| RowExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:00:10 | 11092| odnos| 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| transakcija| 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
Korišćenje istorije zaključavanja za analizu incidenata performansi.
- Zahtjev s queryid=389015618226997618 koji je izvršio proces sa pid=11288 čekao je na blokiranje počevši od 2019-09-17 10:00:00 3 minute.
- Zaključavanje je zadržano procesom sa pid=11092
- Proces s pid=11092 koji izvršava zahtjev sa queryid=389015618226997618 počevši od 2019-09-17 10:00:00 držao je zaključavanje 3 minute.
Rezultat
Sada će, nadam se, početi najzanimljiviji i najkorisniji dio - prikupljanje statistike i analiziranje slučajeva o povijesti čekanja i blokiranja.
Želim da vjerujem da ćemo u budućnosti dobiti set nekih bilješki (slično Oracle-ovom metalink-u).
Općenito, iz tog razloga je korištena metodologija dostupna svima u najkraćem mogućem roku.
Pokušaću da objavim projekat na github u bliskoj budućnosti.
izvor: www.habr.com