Sambungan artikel "
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 -
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.
ΠΡΡ ΠΎΠ΄Π½ΡΠ΅ Π΄Π°Π½Π½ΡΠ΅
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