A comment in the Python source code for float objects acknowledges that: Comparison is pretty much a nightmare This is especially true when comparing a float to an integer, because, unlike floats, integers in Python can be arbitrarily large and are always exact. Trying to cast the integer to a float might lose precision and … Read more
After some additional searching (new search terms inspired by gbn’s answer and u07ch’s comment on KMike’s answer) I found this, which completed successfully in 2 seconds: ALTER DATABASE <dbname> SET OFFLINE WITH ROLLBACK IMMEDIATE (Update) When this still fails with the following error, you can fix it as inspired by this blog post: ALTER DATABASE … Read more
The C# compiler itself doesn’t alter the emitted IL a great deal in the Release build. Notable is that it no longer emits the NOP opcodes that allow you to set a breakpoint on a curly brace. The big one is the optimizer that’s built into the JIT compiler. I know it makes the following … Read more
It’s not that i– is faster than i++. Actually, they’re both equally fast. What takes time in ascending loops is evaluating, for each i, the size of your array. In this loop: for(var i = array.length; i–;) You evaluate .length only once, when you declare i, whereas for this loop for(var i = 1; i … Read more
If your page does not modify any session variables, you can opt out of most of this lock. <% @Page EnableSessionState=”ReadOnly” %> If your page does not read any session variables, you can opt out of this lock entirely, for that page. <% @Page EnableSessionState=”False” %> If none of your pages use session variables, just … Read more
A LEFT JOIN is absolutely not faster than an INNER JOIN. In fact, it’s slower; by definition, an outer join (LEFT JOIN or RIGHT JOIN) has to do all the work of an INNER JOIN plus the extra work of null-extending the results. It would also be expected to return more rows, further increasing the … Read more
Summary Tuples tend to perform better than lists in almost every category: Tuples can be constant folded. Tuples can be reused instead of copied. Tuples are compact and don’t over-allocate. Tuples directly reference their elements. Tuples can be constant folded Tuples of constants can be precomputed by Python’s peephole optimizer or AST-optimizer. Lists, on the … Read more
After performing this test with most modern browsers: https://jsben.ch/wY5fo Currently, the fastest form of loop (and in my opinion the most syntactically obvious). A standard for-loop with length caching var i = 0, len = myArray.length; while (i < len) { // your code i++ } I would say, this is definitely a case where … Read more
TryGetValue will be faster. ContainsKey uses the same check as TryGetValue, which internally refers to the actual entry location. The Item property actually has nearly identical code functionality as TryGetValue, except that it will throw an exception instead of returning false. Using ContainsKey followed by the Item basically duplicates the lookup functionality, which is the … Read more
If you are trying to improve performance, you could try creating a persisted computed column on either a hash or concatenated value of the two columns. Once it is persisted, provided the column is deterministic and you are using “sane” database settings, it can be indexed and / or statistics can be created on it. … Read more