在postgresql中结束掉正在执行的SQL语句操作

结束进程两种方式：

select pg_cancel_backend(pid)

取消后台操作，回滚未提交事物 (select);

select pg_terminate_backend(pid)

中断session，回滚未提交事物(select、update、delete、drop);

select * from pg_stat_activity;

根据datid=10841

select pg_terminate_backend (10841);

补充：postgresql无法在pl / pgsql中开始/结束事务

我正在寻求澄清如何确保plpgsql函数中的原子事务,以及为数据库进行此特定更改设置了隔离级别.

在下面显示的plpgsql函数中,我想确保both的删除和插入成功.当我尝试将它们包装在一个事务中时,我收到一个错误：

错误：无法在pl / pgsql中开始/结束事务.

如果另一个用户在此功能已删除自定义记录之后,但在此函数有机会插入自定义记录之前,为情况(rain,night,45mph)添加了默认行为,下面的函数执行过程中会发生什么？是否有一个隐式事务包装插入和删除,以便如果另一个用户已经更改了此函数引用的任何一个行,两者都将回滚？我可以设置此功能的隔离级别吗？

create function foo(v_weather varchar(10), v_timeofday varchar(10), v_speed varchar(10),
 v_behavior varchar(10))
 returns setof custombehavior
 as $body$
 begin
 -- run-time error if either of these lines is un-commented
 -- start transaction isolation level read committed;
 -- or, alternatively, set transaction isolation level read committed;
  delete from custombehavior 
  where weather = 'rain' and timeofday = 'night' and speed= '45mph' ;
 -- if there is no default behavior insert a custom behavior
 if not exists
  (select id from defaultbehavior where a = 'rain' and b = 'night' and c= '45mph') then 
  insert into custombehavior
  (weather, timeofday, speed, behavior)
  values
  (v_weather, v_timeofday, v_speed, v_behavior);
 end if;
 return query
 select * from custombehavior where ... ;
 -- commit;
 end
 $body$
 language plpgsql

一个plpgsql函数在事务中自动运行.这一切都成功了,一切都失败了.

我引用

functions and trigger procedures are always executed within a transaction established by an outer query — they cannot start or commit that transaction, since there would be no context for them to execute in. however, a block containing an exception clause effectively forms a subtransaction that can be rolled back without affecting the outer transaction.

所以,如果你需要,你可以捕获理论上可能发生的异常(但是不大可能).

details on trapping errors in the manual.

您的功能审查和简化：

create function foo(v_weather text
   , v_timeofday text
   , v_speed text
   , v_behavior text)
 returns setof custombehavior as
$body$
begin
delete from custombehavior
where weather = 'rain'
and timeofday = 'night'
and speed = '45mph';
insert into custombehavior (weather, timeofday, speed, behavior)
select v_weather, v_timeofday, v_speed, v_behavior
where not exists (
 select 1 from defaultbehavior
 where a = 'rain'
 and b = 'night'
 and c = '45mph'
 );
return query
select * from custombehavior where ... ;
end
$body$language plpgsql

以上为个人经验，希望能给大家一个参考，也希望大家多多支持www.887551.com。如有错误或未考虑完全的地方，望不吝赐教。

在postgresql中结束掉正在执行的SQL语句操作

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