Count before order, skip and take - entity-framework

Question

I'm using Entity Framework together with Unit-of-work and repository pattern.
For a function with ordering, pagination, etc. I use the following code:
stammdatenEntityModels =
_unitOfWork.StammdatenRepository.Get()
.Where(
s =>
s.Geloescht == false &&
((s.Auftraggeber != null && s.Auftraggeber.Bezeichnung.ToLower().Contains(keyword)) ||
(s.SerienNummer.Contains(keyword)) ||
(s.Bezeichnung.ToLower().Contains(keyword)) ||
(s.StammdatenKunde != null && s.StammdatenKunde.Name.ToLower().Contains(keyword)) ||
(s.BeginnVos.HasValue && s.BeginnVos == dateTime) ||
(s.VosDauer != null && s.VosDauer.Bezeichnung.ToLower().Contains(keyword)) ||
(s.Geraetewert.HasValue && s.Geraetewert.Value.ToString().Contains(keyword))
))
.OrderBy(orderBy)
.Skip(inputModel.EntriesToDisplay*(inputModel.Page - 1))
.Take(inputModel.EntriesToDisplay)
.ToList();
Now I need to know the numbers of records, but before the skip and take (for pagination) is performed.
Therefore I have the same code again:
totalCount = _unitOfWork.StammdatenRepository.Get()
.Count(
s =>
s.Geloescht == false &&
((s.Auftraggeber != null && s.Auftraggeber.Bezeichnung.ToLower().Contains(keyword)) ||
(s.SerienNummer.Contains(keyword)) ||
(s.Bezeichnung.ToLower().Contains(keyword)) ||
(s.StammdatenKunde != null && s.StammdatenKunde.Name.ToLower().Contains(keyword)) ||
(s.BeginnVos.HasValue && s.BeginnVos == dateTime) ||
(s.VosDauer != null && s.VosDauer.Bezeichnung.ToLower().Contains(keyword)) ||
(s.Geraetewert.HasValue && s.Geraetewert.Value.ToString().Contains(keyword))
));
Unfortunately this leads to a lot of redundance and my query is performed twice. Is there any better solution?

Answer 1

I agree with the redundancy. What you can do is to cache the count result for the specific parameters (keyword, dateTime) a certain amount of time and use it again at subsequent calls to deliver paginated (skip, take) results from the StammDatenRepository.
This way you only have the overall count-call one time for specific parameters.
Found this SO question where a respected member states:
Thinking about it from a SQL point of view, I can't think of a way in
a single normal query to retrieve both the total count and a subset of
the data, so I don't think you will be able to do it in LINQ either.
So, I really think you have to cache some counts results to increase performance. You know best how to do it for your specific situation and if it's worth it at all...