Question

我对数据库的查询有问题。当我尝试下面的代码时，它工作75毫秒并返回空列表。一切都很好。

var test1 = unit
    .PersonQualities.GetAll()
    .Where(qp => qp.QualityId == qualityId && qp.PersonId == targetPersonId)
    .ToList();

但是当我使用它时，它工作30秒并返回超时过期异常：

var test2 = unit
    .PersonQualities.GetAll()
    .FirstOrDefault(qp => qp.QualityId == qualityId && qp.PersonId == targetPersonId);

我的GetAll方法：

public virtual IQueryable<T> GetAll()
{
    return Entities.AsQueryable();
}

请解释为什么会这样。我能做些什么来解决这个问题。谢谢。附：我正在使用SQL Server 2016 Developer。这两个查询都适用于SSMS。

Profiler中的FirstOrDefault查询：

exec sp_executesql N'SELECT TOP (1) 
    [Extent1].[Id] AS [Id], 
    [Extent1].[Value] AS [Value], 
    [Extent1].[Percent] AS [Percent], 
    [Extent1].[IsLocked] AS [IsLocked], 
    [Extent1].[PersonId] AS [PersonId], 
    [Extent1].[QualityId] AS [QualityId]
    FROM [dbo].[PersonQuality] AS [Extent1]
    WHERE ([Extent1].[QualityId] = @p__linq__0) AND ([Extent1].[PersonId] = @p__linq__1)',N'@p__linq__0 bigint,@p__linq__1 bigint',@p__linq__0=110207,@p__linq__1=43257113

的SingleOrDefault：

exec sp_executesql N'SELECT TOP (2) 
    [Extent1].[Id] AS [Id], 
    [Extent1].[Value] AS [Value], 
    [Extent1].[Percent] AS [Percent], 
    [Extent1].[IsLocked] AS [IsLocked], 
    [Extent1].[PersonId] AS [PersonId], 
    [Extent1].[QualityId] AS [QualityId]
    FROM [dbo].[PersonQuality] AS [Extent1]
    WHERE ([Extent1].[QualityId] = @p__linq__0) AND ([Extent1].[PersonId] = @p__linq__1)',N'@p__linq__0 bigint,@p__linq__1 bigint',@p__linq__0=110207,@p__linq__1=43257113

Answer 1

您可能需要更新统计信息并刷新查询缓存。

DBCC FLUSHPROCINDB

和

UPDATE STATISTICS

可能会有所帮助。

IQueryable超时已过期

1 个答案: