LINQ查询生成超时

Question

我有一个查询，看起来像这样：

var TheDataToDelete = (from x in MyDC.SomeTable
                       where x.....
                       select x).ToList();

if (TheDataToDelete.Count > 0)
{
  MyDC.SomeTable.DeleteAllOnSubmit(TheDataToDelete);
  MyDC.SubmitChanges();
}

大约有10K行删除，并在我的错误日志我有时（每周一次）看到此错误：

Inner Exception Type: System.ComponentModel.Win32Exception
Inner Exception: The wait operation timed out
Inner Source: 
Exception Type: System.Data.SqlClient.SqlException
Exception: Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.

这有什么错我的代码和我需要什么改变来解决这个问题？

Answer 1

作为@Shyju建议，使用Any()。还能去除ToList()，因为这将已经执行查询。不加它将使查询有懒惰的执行。而由于那么只有做Any()查询的效率会更高。

var TheDataToDelete = (from x in MyDC.SomeTable
                       where x.....
                       select x);

if (TheDataToDelete.AnY())
{
    MyDC.SomeTable.DeleteAllOnSubmit(TheDataToDelete);
    MyDC.SubmitChanges();
}

这将产生SQL查询;

SELECT
    (CASE
        WHEN EXISTS(
            SELECT x 
            FROM MyDC.SomeTable
            WHERE x
            ) THEN 1
        ELSE 0
     END) AS [value]

这是快速，高效。