Optimiser Groupe Par dans LINQ to entities

J'ai cette requête LINQ to entities.

        var query = (from s in db.ForumStatsSet
                     where s.LogDate >= date1 && s.LogDate <= date2
                     group s by new { s.Topic.topicID, s.Topic.subject, s.Topic.Forum.forumName, s.Topic.datum, s.Topic.Forum.ForumGroup.name, s.Topic.Forum.forumID } into g
                     orderby g.Count() descending
                     select new TopicStatsData
                     {
                         TopicId = g.Key.topicID,
                         Count = g.Count(),
                         Subject = g.Key.subject,
                         ForumGroupName = g.Key.name,
                         ForumName = g.Key.forumName,
                         ForumId = g.Key.forumID
                     });

Je sais que c'est en quelque sorte un "Mal" de la requête, mais il n'est utilisé que dans l'interface d'administration. Mais le SQL générée est absolument horrible. Jetez un oeil à ce bébé.


exec sp_executesql N'SELECT TOP (50) 
[Project6].[C1] AS [C1], 
[Project6].[TopicId] AS [TopicId], 
[Project6].[C4] AS [C2], 
[Project6].[subject] AS [subject], 
[Project6].[name] AS [name], 
[Project6].[forumName] AS [forumName], 
[Project6].[C2] AS [C3]
FROM ( SELECT 
[Project5].[TopicId] AS [TopicId], 
[Project5].[subject] AS [subject], 
[Project5].[forumName] AS [forumName], 
[Project5].[name] AS [name], 
1 AS [C1], 
CAST( [Project5].[forumID] AS int) AS [C2], 
[Project5].[C1] AS [C3], 
[Project5].[C2] AS [C4]
FROM ( SELECT 
[Project4].[TopicId] AS [TopicId], 
[Project4].[forumID] AS [forumID], 
[Project4].[subject] AS [subject], 
[Project4].[forumName] AS [forumName], 
[Project4].[name] AS [name], 
[Project4].[C1] AS [C1], 
(SELECT 
COUNT(cast(1 as bit)) AS [A1]
FROM        [dbo].[tForumStats] AS [Extent14]
LEFT OUTER JOIN [dbo].[tTopic] AS [Extent15] ON [Extent14].[TopicId] = [Extent15].[topicID]
LEFT OUTER JOIN [dbo].[tForum] AS [Extent16] ON [Extent15].[forumID] = [Extent16].[forumID]
LEFT OUTER JOIN [dbo].[tForum] AS [Extent17] ON [Extent15].[forumID] = [Extent17].[forumID]
LEFT OUTER JOIN [dbo].[tForum] AS [Extent18] ON [Extent15].[forumID] = [Extent18].[forumID]
LEFT OUTER JOIN [dbo].[tForumGroup] AS [Extent19] ON [Extent18].[forumGroupID] = [Extent19].[forumGroupID]
LEFT OUTER JOIN [dbo].[tForum] AS [Extent20] ON [Extent15].[forumID] = [Extent20].[forumID]
LEFT OUTER JOIN [dbo].[tForumGroup] AS [Extent21] ON [Extent20].[forumGroupID] = [Extent21].[forumGroupID]
WHERE ([Extent14].[LogDate] >= @p__linq__25) AND ([Extent14].[LogDate] = @p__linq__25) AND ([Extent6].[LogDate] = @p__linq__25) AND ([Extent1].[LogDate] 

I do not as anyone to explain that query but it would be great to get some tips on how to optimze the query so that it just do a simple regular join. Something like this works as fine if I write the SQL myself.

SELECT COUNT(*) AS NumberOfViews, s.topicid AS topicId, t.subject AS TopicSubject, g.[name] AS ForumGroupName, f.forumName AS ForumName 
FROM tForumStats s
join tTopic t on s.topicid = t.topicid
join tForum f on f.forumid = t.forumid
JOIN tForumGroup g ON f.forumGroupID = g.forumGroupID
WHERE s.[LogDate] between @date1 AND @date2
group by s.topicid,  t.subject, f.Forumname, t.Datum, g.[name]
order by count(*) desc

Btw, j'ADORE ce site. Incroyable la conception et la convivialité! Espérons que cela fonctionne bien pour obtenir un peu d'aide:) de

  • De l'espoir, on dirait que le site couper les grandes requête générée bu Linq pour les entités, je ne vous blâme pas. Je pense que vous avez l'idée ..
InformationsquelleAutor Olaj | 2008-11-25