Linq to Entities, Operation timeout when I try to use group .. by - azure

Question

I have the following code:
var statList = (from i in _dbContext.Screenshots
where EntityFunctions.TruncateTime(i.dateTimeServer.Value) >= startDate && EntityFunctions.TruncateTime(i.dateTimeServer.Value) <= endDate
group i by EntityFunctions.TruncateTime(i.dateTimeServer.Value)
into g
select new ScreenshotStatistic()
{
Date = g.Key.Value,
AllScreenshots = g.Count(),
ScreenshotsNoSilent = g.Where(p => p.version.IndexOf("silent") == 0).Count(),
ScreenshotsNoSilentWithViews = g.Where(p => p.version.IndexOf("silent") == 0 && p.viewsPage + p.viewsOriginal > 0).Count(),
ScreenshotsOnlySilent = g.Where(p => p.version.IndexOf("silent") >= 0).Count(),
ScreenshotsOnlySilentWithViews = g.Where(p => p.version.IndexOf("silent") >= 0 && p.viewsPage + p.viewsOriginal > 0).Count(),
ScreenshotsOnlyUploadViaSite = g.Where(p => p.version.IndexOf("UPLOAD_VIA_SITE") >= 0).Count(),
ScreenshotsOnlyUploadViaSiteWithViews = g.Where(p => p.version.IndexOf("UPLOAD_VIA_SITE") >= 0 && p.viewsPage + p.viewsOriginal > 0).Count()
}).ToList();
It works carefully for my local database, but I get "Operation timeout" when I try to connect to SQL Azure. As I understand, my request is not optimized. How can I do the request better?
table has the following structure:
CREATE TABLE [dbo].[Screenshots](
[id] [int] IDENTITY(1,1) NOT NULL,
[dateTimeClient] [datetime] NOT NULL,
[name] [nvarchar](500) NOT NULL,
[username] [varchar](50) NULL,
[filename] [nvarchar](50) NULL,
[description] [nvarchar](500) NULL,
[version] [varchar](50) NULL,
[lang] [varchar](50) NULL,
[dateTimeServer] [datetime] NULL CONSTRAINT [DF_Screenshots_dateTimeServer] DEFAULT (getdate()),
[isPublic] [bit] NOT NULL CONSTRAINT [DF_Screenshots_isPublic] DEFAULT ((0)),
[viewsPage] [int] NOT NULL CONSTRAINT [DF_Screenshots_viewsPage_1] DEFAULT ((0)),
[viewsThumb] [int] NOT NULL CONSTRAINT [DF_Screenshots_viewsThumb_1] DEFAULT ((0)),
[viewsOriginal] [int] NOT NULL CONSTRAINT [DF_Screenshots_viewsOriginal_1] DEFAULT ((0)),
[statusID] [int] NOT NULL,
CONSTRAINT [PK_Screenshots] PRIMARY KEY CLUSTERED
(
[id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
SET ANSI_PADDING OFF
GO
ALTER TABLE [dbo].[Screenshots] WITH CHECK ADD CONSTRAINT [FK_Screenshots_ScreenshotStatuses] FOREIGN KEY([statusID])
REFERENCES [dbo].[ScreenshotStatuses] ([ID])
ON UPDATE CASCADE
ON DELETE CASCADE
GO
ALTER TABLE [dbo].[Screenshots] CHECK CONSTRAINT [FK_Screenshots_ScreenshotStatuses]
GO

Answer 1

EntityFunctions.TruncateTime is being translated into:
convert (datetime2, convert(varchar(255), [dateTimeServer], 102) , 102)
This is causing your query to be non-sargable, resulting in slow performance and timeout. I recommend making the following changes
First off, I do not see why you need to truncate the time in your where clause. I suggest you make this change:
where i.dateTimeServer.Value >= startDate && i.dateTimeServer.Value <= endDate
This will prevent the database from having to run the function on every record.
If the query still times out, I would change the group by to:
group i by new {
i.dateTimeServer.Value.Year,
i.dateTimeServer.Value.Month,
i.dateTimeServer.Value.Day
}
Functionally this is the same, but I believe it produces a more friendly translation:
DATEPART (year, dateTimeServer), DATEPART (month, dateTimeServer) etc..
Add an index to dateTimeServer
If all else fails, you will need to add a column to your table with the time portion truncated. Index it and use it in your query.