PostgreSQL锁浅析

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 ;

with recursive tmp_lock as (
select distinct
--w.mode w_mode,w.page w_page,
--w.tuple w_tuple,w.xact_start w_xact_start,w.query_start w_query_start,
--now()-w.query_start w_locktime,w.query w_query
w.pid as id,--w_pid,
r.pid as parentid--r_pid,
--r.locktype,r.mode r_mode,r.usename r_user,r.datname r_db,
--r.relation::regclass,
--r.page r_page,r.tuple r_tuple,r.xact_start r_xact_start,
--r.query_start r_query_start,
--now()-r.query_start r_locktime,r.query r_query,
from (
select a.mode,a.locktype,a.database,
a.relation,a.page,a.tuple,a.classid,
a.objid,a.objsubid,a.pid,a.virtualtransaction,a.virtualxid,
a.transactionid,
b.query as query,
b.xact_start,b.query_start,b.usename,b.datname
from pg_locks a,
pg_stat_activity b
where a.pid=b.pid
and not a.granted
) w,
(
select a.mode,a.locktype,a.database,
a.relation,a.page,a.tuple,a.classid,
a.objid,a.objsubid,a.pid,a.virtualtransaction,a.virtualxid,
a.transactionid,
b.query as query,
b.xact_start,b.query_start,b.usename,b.datname
from pg_locks a,
pg_stat_activity b -- select pg_typeof(pid) from pg_stat_activity
where a.pid=b.pid
and a.granted
) r
where 1=1
and 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.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.transactionid is not distinct from w.transactionid
and r.pid <> w.pid

),tmp0 as (
select *
from tmp_lock tl
union all
select t1.parentid,0::int4
from tmp_lock t1
where 1=1
and t1.parentid not in (select id from tmp_lock)
),tmp3 (pathid,depth,id,parentid) as (
SELECT array[id]::text[] as pathid,1 as depth,id,parentid
FROM tmp0
where 1=1
and parentid=0
union
SELECT t0.pathid||array[t1.id]::text[] as pathid,t0.depth+1 as depth,t1.id,t1.parentid
FROM tmp0 t1,
tmp3 t0
where 1=1
and t1.parentid=t0.id
)
select distinct
/||array_to_string(a0.pathid,/) as pathid,
a0.depth,
a0.id,a0.parentid,lpad(a0.id::text, 2*a0.depth-1+length(a0.id::text), ) as tree_id,
--select pg_cancel_backend(||a0.id|| ); as cancel_pid,
--select pg_terminate_backend(||a0.id|| ); as term_pid,
case when a0.depth =1 then select pg_terminate_backend(|| a0.id || ); else null end  as term_pid,
case when a0.depth =1 then select cancel_backend(|| a0.id || ); else null end  as cancel_pid
,a2.datname,a2.usename,a2.application_name,a2.client_addr,a2.wait_event_type,a2.wait_event,a2.state
--,a2.backend_start,a2.xact_start,a2.query_start
from tmp3 a0
left outer join (select distinct /||id||/ as prefix_id,id
from tmp0
where 1=1 ) a1
on position( a1.prefix_id in /||array_to_string(a0.pathid,/)||/ ) >0
left outer join pg_stat_activity a2 -- select * from pg_stat_activity
on a0.id = a2.pid
order by /||array_to_string(a0.pathid,/),a0.depth;