正如我所理解的那样,当一个特殊资源信息数据库忙于处理另一个问题时,它就会陷入僵局,因为现在它非常忙.。 服务器“大多”从要求的资源中挑选出一个问题,以打破僵局,而忽略不计。
我有大约40个案例和后台Windows服务,所有这些都击中了同一个数据库。 我期望减少僵局,以便我能够增加我能够同时运行的镜子数量。
你对僵局的理解是不正确的。 你所描述的是阻碍。 把这两者混为一谈是一个常见错误。
当两个单独的交易各自需要不同的资源时,就会出现僵局,而这两个交易都不会释放它们所拥有的资源,以便另一方能够运作。 说明:
SPID #1 gets a lock on resource A SPID #2 gets a lock on resource B SPID #1 now needs a lock on resource B in order to complete SPID #2 now needs a lock on resource A in order to complete
SPID #1 can t complete (and therefor release resource A) because SPID #2 has it SPID #2 can t complete (and therefor release resource B) because SPID #1 has it
Since neither SPID can complete one has to give up (i.e. be chosen by the server as the deadlock victim) and will fail.
避免这些交易的最佳办法是使交易少花(需要多少资源)和快捷。
死锁是两个加工线同时被另一条管束(可能更多,但两条相当复杂)。 因此,一张桌子就座,然后请求在另一个桌子上锁。 另一表被第二线read锁,由于坐在第一桌上,无法取得进展。
必须消除的原因之一是,在僵局中,它们永远不会结束——两者都不可能取得进展。 唯一的答案是阻止对方完成。
The solution to reducing deadlocks in the sort of situation you are talking about may be to redesign the solution. If you can make sure that less locking occurs, you will have less deadlocks.
之所以出现僵局,是因为两个同时进行的交易可能会重叠,使其他交易需要完成的不同资源中断。
Let s imagine: 1 - Transaction A locks row1 2 - Transaction B locks row2 3 - Transaction A tries to lock row1, and, because of the previous lock, SQL server waits 4 - Transaction B tries to lock row2, and, because of the previous lock, SQL server waits
因此,服务器必须选择交易,将其杀死,并允许对方继续交易。
这一形象很好地说明了这一情况:。
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