Entity Framework query slow, but same SQL in SqlQuery is fast

by

Found it. It turns out it’s an issue of SQL data types. The SomeStringProp column in the database was a varchar, but EF assumes that .NET string types are nvarchars. The resulting translation process during the query for the DB to do the comparison is what takes a long time. I think EF Prof was leading me astray a bit here, a more accurate representation of the query being run would be the following:

 SELECT [Extent1].[ID], [Extent1].[SomeStringProp], [Extent1].[SomeOtherProp],
 ...
 FROM [MyTable] as [Extent1]
 WHERE [Extent1].[SomeStringProp] = N'1234567890'

So the resulting fix is to annotate the code-first model, indicating the correct SQL data type:

public class MyTable
{
    ...

    [Column(TypeName="varchar")]
    public string SomeStringProp { get; set; }

    ...
}

More Related Contents:

  1. How many Include I can use on ObjectSet in EntityFramework to retain performance?
  2. Debugging Entity Framework SQL statements
  3. How to avoid Query Plan re-compilation when using IEnumerable.Contains in Entity Framework LINQ queries?
  4. One could use a profiler, but why not just halt the program? [closed]
  5. Why is this SSE code 6 times slower without VZEROUPPER on Skylake?
  6. Faster way to find the first empty row in a Google Sheet column
  7. 32-byte aligned routine does not fit the uops cache
  8. EntityFramework code-first custom connection string and migrations
  9. Multiple DB Contexts in the Same DB and Application in EF 6 and Code First Migrations
  10. Which Intel microarchitecture introduced the ADC reg,0 single-uop special case?
  11. Storing Documents as Blobs in a Database – Any disadvantages?
  12. Can modern x86 implementations store-forward from more than one prior store?
  13. Cellfun versus Simple Matlab Loop performance
  14. timing code in matlab
  15. Minimizing overhead due to the large number of Numpy dot calls
  16. Simulating Slow Internet Connection [closed]
  17. Debug code-first Entity Framework migration codes
  18. What is the difference between spark.sql.shuffle.partitions and spark.default.parallelism?
  19. What’s the actual effect of successful unaligned accesses on x86?
  20. Assembly – How to score a CPU instruction by latency and throughput
  21. Content-Length header versus chunked encoding
  22. How to find pair with kth largest sum?
  23. Does Scala support tail recursion optimization?
  24. EF4 Code First: how to add a relationship without adding a navigation property
  25. How to create index in Entity Framework 6.2 with fluent configuration
  26. Memory Allocation/Deallocation Bottleneck?
  27. Model First with DbContext, Fails to initialize new DataBase
  28. How can the rep stosb instruction execute faster than the equivalent loop?
  29. How to find Cumulative Layout Shift problems if Page Speed Insights says one thing and Search Console says another
  30. SET vs. SELECT – What’s the difference?

Leave a Comment