So performant!

https://devrant.molodetz.nl/Screens...

If I'm not mistaken, this is the slowest possible way to build strings in C#

Also ignore the SQL injection, that is not the point right now and only about 100 people are supposed to have access to the endpoints that can exploit it.

StringBuilder with interpolation, you mean? If it's in a loop it's probably not the slowest.

@lorentz Slowest?

foreach (var c in new[] { " and ", columnExpression, " like ", valueExpression }.SelectMany(x => x)) filter.Append(c);

@lorentz @spongessuck It'll also likely get optimized away. I would be surprised if the CLR doesn't have transformation passes for repeated string concatenations like this

@12bitfloat That's the thing! It does. within roughly a function, C# will replace strings that are repeatedly concatenated with ropes. If the code only used string concatenation, this optimization would kick in and it would be faster than a stringbuilder because although it's not visible on the screenshot, this function basically just does a ton of string concatenation, which would translate into small allocations, most of them static size and therefore stack promotable.

However, stringbuilders don't work with ropes, they work with a buffer, so I think this forces C# to first convert the rope into a CLR string primitive (copy everything together into a newly allocated space) and then copy it to the end of the stringbuilder.

I'm not fully confident that they didn't improve ropes in the mean time, when they were introduced they worked like this, and it wasn't a problem because the idea was to replace stringbuilder with a pattern that requires less forethought to be efficient.