Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>The first time your type is accessed, the static ctor (whether generated explicitly or implicitly) has to be executed.</p> <p>When the JIT compiler compiles IL to native instructions it checks whether the static ctor for that type has been executed and if not emits native code that checks (again) whether the static ctor has been executed and if not, executes it.</p> <p>The jitted code is cached for future calls of the same method (and this is why the code had to check again if the static ctor was executed).</p> <p>The thing is, if the jitted code that checks for the static ctor is in a loop, this test will occur in every iteration.</p> <p>When beforefieldinit is present, the JIT compiler is allowed to optimize the code, by testing for the static ctor invocation BEFORE entering the loop. If it's not present, this optimization is not allowed.</p> <p>The C# compiler automatically decides for us when to emit this attribute. It currently (C# 4) emits it only if the code does NOT explicitly defines a static constructor. The idea behind it is if you defined a static ctor yourself, the timing might be more important to you and the ststic ctor should not execute ahead of time. This may or may not be true, but you can't change this behavior.</p> <p>Here is a link to the part of my online .NET tutorial that explain this in detail: <a href="http://motti.me/c1L">http://motti.me/c1L</a></p> <p>BTW, I don't recommend using static ctors on structs because believe it or not, they are not guaranteed to execute! This wasn't part of the question, so I won't elaborate, but see this for more detail if your'e interested: <a href="http://motti.me/c1I">http://motti.me/c1I</a> (I touch the subject at about 2:30 into the video).</p> <p>I hope this helps!</p>
    singulars
    1. This table or related slice is empty.
    1. POStatic constructor performance and why we can't specify beforefieldinit
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USMotti Shaked
    1. USMotti Shaked
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POStatic constructor performance and why we can't specify beforefieldinit
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. CONot using static ctors on structs is great advice. I'm very aware about how the CLR may not always execute it. Now, when taking into account the pastebin link in my first edit, the JITer is putting the static ctor checks in *both* loops that involve `StaticCtor.GetMyValue()` instead of only in the first for loop, even though the JITer knows it's placed the check earlier in code. Essentially, in any function that a static ctor has not yet been called, it will put that check before *EVERY* access not just the first, is that correct?
      singulars
      1. PO
      1. USChristopher Currens
    2. COHmm, by testing it seems that as you said, the JIT compiler makes the decision whether to put the test on a per jitted method basis. I modified your code to two separate methods per each call (with & without ctor) and got the performance boost for the second time: http://pastebin.com/WyQWz5ar. I’m not sure whether this is documented or an implementation detail, which could change at any update of the JIT compiler. Also, as I’m sure you're aware, the JIT compiler implementation could be different between platforms.
      singulars
      1. PO
      1. USMotti Shaked
    3. COYeah, I just found it interesting. As I commented above, I'm in a phase where I just want to mess around/understand the CLR, and this behavior popped up. I'm fascinated by how the JIT decides when and what to do. Thanks! :)
      singulars
      1. PO
      1. USChristopher Currens
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload