Entity Framework Timeout - entity-framework

Question

I have been trying to figure out how to optimize the following query for the past few days and just not having much luck. Right now my test db is returning about 300 records with very little nested data, but it's taking 4-5 seconds to run and the SQL being generated by LINQ is awfully long (too long to include here). Any suggestions would be very much appreciated.
To sum up this query, I'm trying to return a somewhat flattened "snapshot" of a client list with current status. A Party contains one or more Clients who have Roles (ASPNET Role Provider), Journal is returning the last 1 journal entry of all the clients in a Party, same goes for Task, and LastLoginDate, hence the OrderBy and FirstOrDefault functions.
Guid userID = 'some user ID'
var parties = Parties.Where(p => p.BrokerID == userID).Select(p => new
{
ID = p.ID,
Title = p.Title,
Goal = p.Goal,
Groups = p.Groups,
IsBuyer = p.Clients.Any(c => c.RolesInUser.Any(r => r.Role.LoweredName == "buyer")),
IsSeller = p.Clients.Any(c => c.RolesInUser.Any(r => r.Role.LoweredName == "seller")),
Journal = p.Clients.SelectMany(c => c.Journals).OrderByDescending(j => j.OccuredOn).Select(j=> new
{
ID = j.ID,
Title = j.Title,
OccurredOn = j.OccuredOn,
SubCatTitle = j.JournalSubcategory.Title
}).FirstOrDefault(),
LastLoginDate = p.Clients.OrderByDescending(c=>c.LastLoginDate).Select(c=>c.LastLoginDate).FirstOrDefault(),
MarketingPlanCount = p.Clients.SelectMany(c => c.MarketingPlans).Count(),
Task = p.Tasks.Where(t=>t.DueDate != null && t.DueDate > DateTime.Now).OrderBy(t=>t.DueDate).Select(t=> new
{
ID = t.TaskID,
DueDate = t.DueDate,
Title = t.Title
}).FirstOrDefault(),
Clients = p.Clients.Select(c => new
{
ID = c.ID,
FirstName = c.FirstName,
MiddleName = c.MiddleName,
LastName = c.LastName,
Email = c.Email,
LastLogin = c.LastLoginDate
})
}).OrderBy(p => p.Title).ToList()

Answer 1

I think posting the SQL could give us some clues, as small things like the order of OrderBy coming before or after the projection could make a big difference.
But regardless, try extracting the Clients in a seperate query, this will simplify your query probably. And then include other tables like Journal and Tasks before projecting and see how this affects your query:
//am not sure what the exact query would be, and project it using ToList()
var clients = GetClientsForParty();
var parties = Parties.Include("Journal").Include("Tasks")
.Where(p=>p.BrokerID == userID).Select( p => {
....
//then use the in-memory clients
IsBuyer = clients.Any(c => c.RolesInUser.Any(r => r.Role.LoweredName == "buyer")),
...
}
)
In all cases, install EF profiler and have a look at how your query is affected. EF can be quiet surprising. Something like putting OrderBy before the projection, the same for all these FirstOrDefault or SingleOrDefault, they can all have a big effect.
And go back to the basics, if you are searching on LoweredRoleName, then make sure it is indexed so that the query is fast (even though that could be useless since EF could end up not making use of the covering index since it is querying so many other columns).
Also, since this is query is to view data (you will not alter data), don't forget to turn off Entity tracking, that will give you some performance boost as well.
And last, don't forget that you could always write your SQL query directly and project to your a ViewModel rather than anonymous type (which I see as a good practice anyhow) so create a class called PartyViewModel that includes the flatten view you are after, and use it with your hand-crafted SQL
//use your optimized SQL query that you write or even call a stored procedure
db.Database.SQLQuery("select * from .... join .... on");
I am writing a blog post about these issues around EF. The post is still not finished, but all in all, just be patient, use some of these tricks and observe their effect (and measure it) and you will reach what you want.