Is Entity Framework faster than ado.net for Queries?
My test shows that ado.net is faster than Entity Framework in querying.Why?
ADO.Net is used by EF under the scenes. This means that overall EF is always going to be slower than ADO.Net (assuming they both are generating similar SQL statements)
However I have observed an interesting performance characteristic with EF5 vs ADO.Net and a low number of rows (either queried or inserted). EF5 appears to be consistently faster than ADO.net for under 10 items. I imagine this is due to an optimisation at connection setup time however I haven't yet tracked down what this is.
My results around this and a little more explanation is avaliable here
If anyone has any more information around why EF5 appears so fast on small datasets I would love to hear.
NOTE in this post I actually don't show the raw ADO.net results but they are very similar to the dapper results. I actually wanted to answer this specific question before posting the ADO.Net results :)
Related
I would like to ask the Entity Framework Core team what their ambition is for the scope/complexity of query translation compared to EF6.
I've used EF6 extensively and I know that if you can express it in LINQ and don't use any untranslatable functions, EF can probably translate the query correctly.
Will Entity Framework's translation be eventually as good as that, or is that something that is considered secondary, like the lazy loading feature.
If so, about what is the team eventually aiming at compare to EF6?
There's a ticket discussing GroupBy that appears to indicate they deem grouping an advanced type of query, but compared to what EF6 can translate, a normal group-by is pretty average.
(I'm asking here as the EF Core team says on it's site it is monitoring SO for questions.)
We took a very different approach in EF Core. Every LINQ query should work--even if you use untranslatable functions. We do this by translating the parts of the query we can into SQL and processing the rest on the client after the results are returned by the server. As EF Core evolves, we'll translate more and more of the query into SQL (e.g. GROUP BY) which can make it more efficient.
In theory, our goal is to translate everything that the store supports. In some cases however (especially on NoSQL stores) there simply is no translation for a LINQ operator, and we feel it's better to be functional and inefficient than to throw.
If you want to ensure your whole query is translated, you can disable client evaluation. This will cause it to throw like EF6.
I am using Entity Framework 4.1 code first with no stored procedures. And I would like to know a general opinion on the performance of this on huge applications seeing that it generates the SQL in the background. Doesn't this go against best practices of not using stored procedures? How do you fine tune these generated code?
I know you can hack into it to use stored procedures, but is there definately going to be support for stored procedures and the other functions you get with going with the database first option?
Does EF 4.1 have any improvements on the database first option? How would I know if I have the latest version of EF?
The generated SQL is reasonably efficient, but although I've not resorted to SP's as yet, I have written some views (in 4.0) and written LINQ against those in places in order to overcome some performance issues.
Does 4.1 go against best practices of stored procedures ? Well there SP's are best practice for a number of reasons - performance is one, isolation and abstraction of the underlying table structure from your code is another. The performance part of this seems to have been abandoned as "probably not that important these days" for reasons that don't smell 100% to me. And the abstraction issue - well you are using EF Code First for a reason - that reason is that you are looking for a persistence framework for your applications objects: by the very act of choosing EF Code First, you are declaring that you don't want to know how they are stored, in what structures, and what happens to get them back.
How do you tune it ? Mainly by being very careful about lazy loading, by monitoring what's going on at the SQL end (EFProf is one tool, MSSql query profiling works too) and generally by fiddling with things.
To ensure you are running the latest EF (if you have been running the CodeFirst CTP) use the NuGet console and
uninstall-package EFCodeFirst
install-package EntityFramework
4.1 has improvements over 4.0 for database first - namely the lightweight dbContext
EDIT: Adding code as requested...
Simple case
foreach (var order in orders) y=order.orderlines.tolist();
which you fix with
foreach (var order in orders.Include("orderlines").tolist()) y=order.orderlines.tolist();
but less obvious is
foreach (var order in orders.Include("orderlines").tolist()) dothing(order);
where
public void dothing(Orderline ol)
{
if (ol.order.property=true)
....
}
to fix this I think you need
foreach (var order in orders.Include("orderlines.orders").tolist()) dothing(order);
(or better still refactor dothing(Orderline ol) to dothing(Orderline ol, Order ord). My point is that with a local database its incredibly easy to miss these. Its only when you profile the sql, or connect to an SQL database on a slow network (think Azure) or just get serious load, that this begins to hurt!
We're currently a Linq to SQL shop but evaluating Entity Framework. One thing that always frustrated me with L2S is how messy the DBML canvas became after putting more than say a couple dozen tables on it. It just became one large mess.
I'm wondering if EF handles this any better? What would be ideal (for us) is the ability to have a separate EDM for each of our schema's. That would keep things very neat and tidy. However, I don't know then how we would establish relationships across EDM's.
Can anyone tell me how (or if) EF handles this sort of thing?
Just my 2 cents.
I deeply recommend you to throw away dbml and edmx as well, and move to EF 4.1 code first. It will give you all the power and flexybility you need.
For me it was a no turning back ever. You can find excellent posts of Scott Guthrie about it if you google a little.
Handling this in EDMX is possible but still it is far away from nice or ideal solution especially because it is not supported by designer - you will work with EDMX as XML. Also relations can be only one way, bidirectional relations between EDMX are not supported. ADO.NET team described the whole process on their blog.
If you have separate schema for some set of tables then tables probably represent some separate business domain where the connection to other schemas are not so common. Perhaps isolating the schema in completely separate model (EDMX) can be way to go.
What is faster - ADO.NET or ADO.NET Entity Framework?
Nothing is faster than an ADO.NET datareader.
Entity framework also uses this in "the basement".
However entitity framework helps you to map from database to objects..
With ADO.NET you have to do that yourself.
It depends on how you program it how fast it is..
When you use ADO.NET datatables as "objects". They are a bit slower and memory hungry than plain objects..
As Julian de Wit says nothing is faster than ADO.NET DataReaders.
ADO.NET Entity Framework is a wrapper to the old ADO.NET.
It is pure Provider independent, ORM and EDL System.
It gives us a lot of benefits that we have had to hand craft or "copy & paste" in the past.
Another benefit that comes with it is that is completely Provider independent.
Even if you like the old ADO.NET mechanism or you are a dinosaur like me(:P) you can use the Entity Framework using the EntityClient like SqlClient, MySqlClient and use the power of Entity-Sql witch is provider independent.
I Know that with ADO.NET you can write a data access Layer and the DataReaders etc can be "independent" but you have steal have Queries that are provider specific.
On the other hand,in an enterprise application you may never want to change the data provider.
But as the technology grows, always new needs arise and you may want have to alter the database schema.
When it happens with the old ADO.NET Framework we have to refactor alot of code which is less than maintainable, no matter how we reuse the code.
The performance will be affected but with all these cache technologies out there we can overcome this.
As i always say, "The C is fast, the Assembly even more...but we use C#/VB.NET/Java"
I am using Entity Framework to layer on my SQL Server 2008 database. The EF is present in my web service and the webservice is invoked by a Silverlight client.
I am seeing a serious performance issue in terms of the duration taken by a query to execute in the EF. This wouldn't happen in the consecutive calls.
A little bit of googling revealed that, it's caused per app domain to construct the in-memory model of the db objects. I found this Microsoft link explaining pre-generation of views for performance improvement. Even after implementing the steps, the performance actually degraded instead of improving. I am curious, if anyone has tried this approach successfully and if there are any other avenues for improving performance.
I am using .NET 3.5.
A couple areas to look at for EF performance
Do as much of the processing before calling things like tolist(). ToList will bring everything in the set into memory. By default, EF will keep building the expression tree and only actually process it when you need the data in memory. That first query will be against the database, but afterwards the processing will be in memory. When working with large data, you definitely want as much of the heavy lifting done by the database as possible.
EF 1 only has the option to pull the entire row back. Therefore if you have a column that is a large string or binary blob, it is going to be pulled down and into memory whether you need it or not. You can create a projection that doesn't include this column, but then you don't get the benefits of having it be an entity.
You can look at the sql generated by EF using the suggestion in this post
How do I view the SQL generated by the Entity Framework?
The same laws of physics apply for EF queries as they do for ordinary SQL. Check your database tables and make sure that you have indexes on primary and foreign keys, that your database is properly normalized, and so forth. If performance is degrading after Microsoft's suggestions, then that's my guess as to the problem area.
Are you hosting the webservice in IIS? Is it running on the same site as the Silverlight App? What about the database itself? Is it running on a dedicated machine? Are there other apps hitting it? The first call to a dormant database is painful (I've had situations where it would actually time out in my environment.)
There are a number of factors to take into consideration here. But it comes down to more than just EF's overhead.
edit I didn't fully qualify but the process of opening the first connection to SQL Server is slow regardless of your data access solution.
Use SQL Profiler to check how many queries executed to retrieve your data.If it's large number use Include() method of ObjectQuery to retrieve child objects with parent in one query.