PostgreSQL 锁等待监控 珍藏级SQL
查看当前事务锁等待、持锁信息的SQL
这条SQL非常有用，建议DBA珍藏。
with
t_wait as
(
select a.mode,a.locktype,a.database,a.relation,a.page,a.tuple,a.classid,a.granted,
a.objid,a.objsubid,a.pid,a.virtualtransaction,a.virtualxid,a.transactionid,a.fastpath,
b.state,b.query,b.xact_start,b.query_start,b.usename,b.datname,b.client_addr,b.client_port,b.application_name
from pg_locks a,pg_stat_activity b where a.pid=b.pid and not a.granted
),
t_run as
(
select a.mode,a.locktype,a.database,a.relation,a.page,a.tuple,a.classid,a.granted,
a.objid,a.objsubid,a.pid,a.virtualtransaction,a.virtualxid,a.transactionid,a.fastpath,
b.state,b.query,b.xact_start,b.query_start,b.usename,b.datname,b.client_addr,b.client_port,b.application_name
from pg_locks a,pg_stat_activity b where a.pid=b.pid and a.granted
),
t_overlap as
(
select r.* from t_wait w join t_run r on
(
r.locktype is not distinct from w.locktype and
r.database is not distinct from w.database and
r.relation is not distinct from w.relation and
r.page is not distinct from w.page and
r.tuple is not distinct from w.tuple and
r.virtualxid is not distinct from w.virtualxid and
r.transactionid is not distinct from w.transactionid and
r.classid is not distinct from w.classid and
r.objid is not distinct from w.objid and
r.objsubid is not distinct from w.objsubid and
r.pid <> w.pid
)
),
t_unionall as
(
select r.* from t_overlap r
union all
select w.* from t_wait w
)
select locktype,datname,relation::regclass,page,tuple,virtualxid,transactionid::text,classid::regclass,objid,objsubid,
string_agg(
'Pid: '||case when pid is null then 'NULL' else pid::text end||chr(10)||
'Lock_Granted: '||case when granted is null then 'NULL' else granted::text end||' , Mode: '||case when mode is null then 'NULL' else mode::text end||' , FastPath: '||case when fastpath is null then 'NULL' else fastpath::text end||' , VirtualTransaction: '||case when virtualtransaction is null then 'NULL' else virtualtransaction::text end||' , Session_State: '||case when state is null then 'NULL' else state::text end||chr(10)||
'Username: '||case when usename is null then 'NULL' else usename::text end||' , Database: '||case when datname is null then 'NULL' else datname::text end||' , Client_Addr: '||case when client_addr is null then 'NULL' else client_addr::text end||' , Client_Port: '||case when client_port is null then 'NULL' else client_port::text end||' , Application_Name: '||case when application_name is null then 'NULL' else application_name::text end||chr(10)||
'Xact_Start: '||case when xact_start is null then 'NULL' else xact_start::text end||' , Query_Start: '||case when query_start is null then 'NULL' else query_start::text end||' , Xact_Elapse: '||case when (now()-xact_start) is null then 'NULL' else (now()-xact_start)::text end||' , Query_Elapse: '||case when (now()-query_start) is null then 'NULL' else (now()-query_start)::text end||chr(10)||
'SQL (Current SQL in Transaction): '||chr(10)||
case when query is null then 'NULL' else query::text end,
chr(10)||'--------'||chr(10)
order by
( case mode
when 'INVALID' then 0
when 'AccessShareLock' then 1
when 'RowShareLock' then 2
when 'RowExclusiveLock' then 3
when 'ShareUpdateExclusiveLock' then 4
when 'ShareLock' then 5
when 'ShareRowExclusiveLock' then 6
when 'ExclusiveLock' then 7
when 'AccessExclusiveLock' then 8
else 0
end ) desc,
(case when granted then 0 else 1 end)
) as lock_conflict
from t_unionall
group by
locktype,datname,relation,page,tuple,virtualxid,transactionid::text,classid,objid,objsubid ;
如果觉得写SQL麻烦，可以将它创建为视图
create view v_locks_monitor as
with
t_wait as
(
select a.mode,a.locktype,a.database,a.relation,a.page,a.tuple,a.classid,a.granted,
a.objid,a.objsubid,a.pid,a.virtualtransaction,a.virtualxid,a.transactionid,a.fastpath,
b.state,b.query,b.xact_start,b.query_start,b.usename,b.datname,b.client_addr,b.client_port,b.application_name
from pg_locks a,pg_stat_activity b where a.pid=b.pid and not a.granted
),
t_run as
(
select a.mode,a.locktype,a.database,a.relation,a.page,a.tuple,a.classid,a.granted,
a.objid,a.objsubid,a.pid,a.virtualtransaction,a.virtualxid,a.transactionid,a.fastpath,
b.state,b.query,b.xact_start,b.query_start,b.usename,b.datname,b.client_addr,b.client_port,b.application_name
from pg_locks a,pg_stat_activity b where a.pid=b.pid and a.granted
),
t_overlap as
(
select r.* from t_wait w join t_run r on
(
r.locktype is not distinct from w.locktype and
r.database is not distinct from w.database and
r.relation is not distinct from w.relation and
r.page is not distinct from w.page and
r.tuple is not distinct from w.tuple and
r.virtualxid is not distinct from w.virtualxid and
r.transactionid is not distinct from w.transactionid and
r.classid is not distinct from w.classid and
r.objid is not distinct from w.objid and
r.objsubid is not distinct from w.objsubid and
r.pid <> w.pid
)
),
t_unionall as
(
select r.* from t_overlap r
union all
select w.* from t_wait w
)
select locktype,datname,relation::regclass,page,tuple,virtualxid,transactionid::text,classid::regclass,objid,objsubid,
string_agg(
'Pid: '||case when pid is null then 'NULL' else pid::text end||chr(10)||
'Lock_Granted: '||case when granted is null then 'NULL' else granted::text end||' , Mode: '||case when mode is null then 'NULL' else mode::text end||' , FastPath: '||case when fastpath is null then 'NULL' else fastpath::text end||' , VirtualTransaction: '||case when virtualtransaction is null then 'NULL' else virtualtransaction::text end||' , Session_State: '||case when state is null then 'NULL' else state::text end||chr(10)||
'Username: '||case when usename is null then 'NULL' else usename::text end||' , Database: '||case when datname is null then 'NULL' else datname::text end||' , Client_Addr: '||case when client_addr is null then 'NULL' else client_addr::text end||' , Client_Port: '||case when client_port is null then 'NULL' else client_port::text end||' , Application_Name: '||case when application_name is null then 'NULL' else application_name::text end||chr(10)||
'Xact_Start: '||case when xact_start is null then 'NULL' else xact_start::text end||' , Query_Start: '||case when query_start is null then 'NULL' else query_start::text end||' , Xact_Elapse: '||case when (now()-xact_start) is null then 'NULL' else (now()-xact_start)::text end||' , Query_Elapse: '||case when (now()-query_start) is null then 'NULL' else (now()-query_start)::text end||chr(10)||
'SQL (Current SQL in Transaction): '||chr(10)||
case when query is null then 'NULL' else query::text end,
chr(10)||'--------'||chr(10)
order by
( case mode
when 'INVALID' then 0
when 'AccessShareLock' then 1
when 'RowShareLock' then 2
when 'RowExclusiveLock' then 3
when 'ShareUpdateExclusiveLock' then 4
when 'ShareLock' then 5
when 'ShareRowExclusiveLock' then 6
when 'ExclusiveLock' then 7
when 'AccessExclusiveLock' then 8
else 0
end ) desc,
(case when granted then 0 else 1 end)
) as lock_conflict
from t_unionall
group by
locktype,datname,relation,page,tuple,virtualxid,transactionid::text,classid,objid,objsubid ;
例子
postgres=# create table locktest(id int primary key, info text);
CREATE TABLE
postgres=# insert into locktest values (1,'a');
INSERT 0 1
会话A
postgres=# begin;
BEGIN
postgres=# update locktest set info='a' where id=1;
UPDATE 1
postgres=# select * from locktest ;
id | info
----+------
1 | a
(1 row)
会话B
postgres=# begin;
BEGIN
postgres=# select * from locktest ;
id | info
----+------
1 | a
(1 row)
会话C
postgres=# begin;
BEGIN
postgres=# insert into locktest values (2,'test');
INSERT 0 1
会话D
postgres=# begin;
BEGIN
postgres=# truncate locktest ;
waiting......
会话E
postgres=# select * from locktest ;
waiting......
会话F
postgres=# \x
Expanded display is on.
postgres=# select * from v_locks_monitor ;
-[ RECORD 1 ]-+------------------------------------------------------------------------------------------------------------------------------------------------------
locktype | relation
datname | postgres
relation | locktest
page |
tuple |
virtualxid |
transactionid |
classid |
objid |
objsubid |
string_agg | Pid: 23043 +
| Granted: false , Mode: AccessExclusiveLock , FastPath: false , VirtualTransaction: 4/1450064 , Session_State: active +
| Username: postgres , Database: postgres , Client_Addr: NULL , Client_Port: -1 , Application_Name: psql +
| Xact_Start: 2017-05-21 21:43:43.735829+08 , Query_Start: 2017-05-21 21:43:50.965797+08 , Xact_Elapse: 00:01:11.919991 , Query_Elapse: 00:01:04.690023+
| Query: truncate locktest ; +
| -------- +
| Pid: 40698 +
| Granted: true , Mode: RowExclusiveLock , FastPath: false , VirtualTransaction: 6/1031925 , Session_State: idle in transaction +
| Username: postgres , Database: postgres , Client_Addr: NULL , Client_Port: -1 , Application_Name: psql +
| Xact_Start: 2017-05-21 21:43:15.173798+08 , Query_Start: 2017-05-21 21:43:24.338804+08 , Xact_Elapse: 00:01:40.482022 , Query_Elapse: 00:01:31.317016+
| Query: insert into locktest values (2,'test'); +
| -------- +
| Pid: 17515 +
| Granted: true , Mode: RowExclusiveLock , FastPath: false , VirtualTransaction: 3/5671759 , Session_State: idle in transaction +
| Username: postgres , Database: postgres , Client_Addr: NULL , Client_Port: -1 , Application_Name: psql +
| Xact_Start: 2017-05-21 21:42:19.199124+08 , Query_Start: 2017-05-21 21:42:47.820125+08 , Xact_Elapse: 00:02:36.456696 , Query_Elapse: 00:02:07.835695+
| Query: select * from locktest ; +
| -------- +
| Pid: 17515 +
| Granted: true , Mode: RowExclusiveLock , FastPath: false , VirtualTransaction: 3/5671759 , Session_State: idle in transaction +
| Username: postgres , Database: postgres , Client_Addr: NULL , Client_Port: -1 , Application_Name: psql +
| Xact_Start: 2017-05-21 21:42:19.199124+08 , Query_Start: 2017-05-21 21:42:47.820125+08 , Xact_Elapse: 00:02:36.456696 , Query_Elapse: 00:02:07.835695+
| Query: select * from locktest ; +
| -------- +
| Pid: 40698 +
| Granted: true , Mode: RowExclusiveLock , FastPath: false , VirtualTransaction: 6/1031925 , Session_State: idle in transaction +
| Username: postgres , Database: postgres , Client_Addr: NULL , Client_Port: -1 , Application_Name: psql +
| Xact_Start: 2017-05-21 21:43:15.173798+08 , Query_Start: 2017-05-21 21:43:24.338804+08 , Xact_Elapse: 00:01:40.482022 , Query_Elapse: 00:01:31.317016+
| Query: insert into locktest values (2,'test'); +
| -------- +
| Pid: 40199 +
| Granted: true , Mode: AccessShareLock , FastPath: false , VirtualTransaction: 5/1029276 , Session_State: idle in transaction +
| Username: postgres , Database: postgres , Client_Addr: NULL , Client_Port: -1 , Application_Name: psql +
| Xact_Start: 2017-05-21 21:43:01.745129+08 , Query_Start: 2017-05-21 21:43:05.928125+08 , Xact_Elapse: 00:01:53.910691 , Query_Elapse: 00:01:49.727695+
| Query: select * from locktest ; +
| -------- +
| Pid: 17515 +
| Granted: true , Mode: AccessShareLock , FastPath: false , VirtualTransaction: 3/5671759 , Session_State: idle in transaction +
| Username: postgres , Database: postgres , Client_Addr: NULL , Client_Port: -1 , Application_Name: psql +
| Xact_Start: 2017-05-21 21:42:19.199124+08 , Query_Start: 2017-05-21 21:42:47.820125+08 , Xact_Elapse: 00:02:36.456696 , Query_Elapse: 00:02:07.835695+
| Query: select * from locktest ; +
| -------- +
| Pid: 40199 +
| Granted: true , Mode: AccessShareLock , FastPath: false , VirtualTransaction: 5/1029276 , Session_State: idle in transaction +
| Username: postgres , Database: postgres , Client_Addr: NULL , Client_Port: -1 , Application_Name: psql +
| Xact_Start: 2017-05-21 21:43:01.745129+08 , Query_Start: 2017-05-21 21:43:05.928125+08 , Xact_Elapse: 00:01:53.910691 , Query_Elapse: 00:01:49.727695+
| Query: select * from locktest ; +
| -------- +
| Pid: 17515 +
| Granted: true , Mode: AccessShareLock , FastPath: false , VirtualTransaction: 3/5671759 , Session_State: idle in transaction +
| Username: postgres , Database: postgres , Client_Addr: NULL , Client_Port: -1 , Application_Name: psql +
| Xact_Start: 2017-05-21 21:42:19.199124+08 , Query_Start: 2017-05-21 21:42:47.820125+08 , Xact_Elapse: 00:02:36.456696 , Query_Elapse: 00:02:07.835695+
| Query: select * from locktest ; +
| -------- +
| Pid: 24781 +
| Granted: false , Mode: AccessShareLock , FastPath: false , VirtualTransaction: 7/1025270 , Session_State: active +
| Username: postgres , Database: postgres , Client_Addr: NULL , Client_Port: -1 , Application_Name: psql +
| Xact_Start: 2017-05-21 21:44:20.725834+08 , Query_Start: 2017-05-21 21:44:20.725834+08 , Xact_Elapse: 00:00:34.929986 , Query_Elapse: 00:00:34.929986+
| Query: select * from locktest ;
处理方法
1. 前面的锁查询SQL，已经清晰的显示了每一个发生了锁等待的对象，按锁的大小排序，要快速解出这种状态，terminate最大的锁对应的PID即可。
postgres=# select pg_terminate_backend(23043);
-[ RECORD 1 ]--------+--
pg_terminate_backend | t
会话D
FATAL: terminating connection due to administrator command
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Succeeded.
干掉23043后，大家都清净了
postgres=# select * from v_locks_monitor ;
(0 rows)
转载：http://www.360doc.com/content/20/0415/09/69535774_906149767.shtml
参考来自dba大佬的回答：https://developer.aliyun.com/ask/54578?spm=a2c6h.13159736
