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。如有错误或未考虑完全的地方,望不吝赐教。