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[英]SQL Server 2008 R2 DeadLock on query Notification (SqlDependency)
[英]Deadlock executing Query in Sql Server
我有以下 Linq:
var qry = s.GetTable<MessageEventDTO>().Where(x => x.MessageName == messageName && x.SourceTyp == sourceTyp && x.Source == source && (x.Status == MessageEventStatus.open || x.Status == MessageEventStatus.acknowledged));
goneMessages = qry.ToList();
var ret = qry
.Set(x => x.Status, x => x.Status | MessageEventStatus.gone)
.Set(x => x.TimestampGone, timeStamp)
.Update();
return ret;
它将转换为以下 SQL:
UPDATE MessageEvents SET Status = Status | 1, TimeStampGone = @1
WHERE MessageName = @2 AND SourceTyp = @3 Source = @4 AND (Status = 0 OR Status = 2)
现在的问题是,有多个更新并行运行,我得到了死锁异常,但我不明白为什么?
如果您不希望其他进程能够启动更新的选择部分,请使用UPDLOCK
提示或设置适当的事务隔离级别 ( REPEATABLE READ
)。
有关非聚集索引如何导致死锁的更详细说明,请参阅John Huang 的博客。
使用 Linq to SQL 的示例不受此问题的影响:
var opts = new TransactionOptions();
opts.IsolationLevel = IsolationLevel.RepeatableRead;
using (var txn = new TransactionScope(TransactionScopeOption.Required, opts))
{
// update command goes here.
txn.Complete();
}
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