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the manual on plpgsql functions:
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$body$BEGINDELETE FROM custombehaviorWHERE weather = 'RAIN'AND timeofday = 'NIGHT'AND speed = '45MPH';
INSERT INTO custombehavior (weather, timeofday, speed, behavior)SELECT v_weather, v_timeofday, v_speed, v_behaviorWHERE NOT EXISTS ( SELECT 1 FROM defaultbehavior WHERE a = 'RAIN' AND b = 'NIGHT' AND c = '45MPH' );
RETURN QUERYSELECT * 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。
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