Counterintuitively, the fastest version, on Hotspot 8, is: MyClass[] arr = myList.toArray(new MyClass[0]); I have run a micro benchmark using jmh the results and code are below, showing that the version with an empty array consistently outperforms the version with a presized array. Note that if you can reuse an existing array of the correct … Read more
First, it’s worth noting that by “slow,” we’re talking about something that can take tens of nanoseconds. For trivial native methods, in 2010 I measured calls at an average 40 ns on my Windows desktop, and 11 ns on my Mac desktop. Unless you’re making many calls, you’re not going to notice. That said, calling … Read more
I am aware of 5 general categories where recompiling a C++03 compiler as C++11 can cause unbounded performance increases that are practically unrelated to quality of implementation. These are all variations of move semantics. std::vector reallocate struct bar{ std::vector<int> data; }; std::vector<bar> foo(1); foo.back().data.push_back(3); foo.reserve(10); // two allocations and a delete occur in C++03 every … Read more
The VARCHAR(MAX) type is a replacement for TEXT. The basic difference is that a TEXT type will always store the data in a blob whereas the VARCHAR(MAX) type will attempt to store the data directly in the row unless it exceeds the 8k limitation and at that point it stores it in a blob. Using … Read more
try has almost no expense at all. Instead of doing the work of setting up the try at runtime, the code’s metadata is structured at compile time such that when an exception is thrown, it now does a relatively expensive operation of walking up the stack and seeing if any try blocks exist that would … Read more
According to this site, this is supported in the playbackRate and defaultPlaybackRate attributes, accessible via the DOM. Example: /* play video twice as fast */ document.querySelector(‘video’).defaultPlaybackRate = 2.0; document.querySelector(‘video’).play(); /* now play three times as fast just for the heck of it */ document.querySelector(‘video’).playbackRate = 3.0; The above works on Chrome 43+, Firefox 20+, IE … Read more
Try: tourists.removeAll(Collections.singleton(null)); Read the Java API. The code will throw java.lang.UnsupportedOperationException for immutable lists (such as created with Arrays.asList); see this answer for more details.
Being FAST and handling lots of LOAD are two different things. A server that’s really FAST at serving one request per second might totally croak if you send it 500 requests per second (under LOAD). You also have to consider static (and cached) vs dynamic pages. If you’re worried about static pages, then IIS is … Read more
I had the exact same problem myself. Given the fact that you want to collect a large amount of this data and not a specific set of 30 you’ll be probably running a loop and incrementing the offset by 30. So what you can do instead is: Hold the last id of a set of … Read more
Generally speaking, IN and JOIN are different queries that can yield different results. SELECT a.* FROM a JOIN b ON a.col = b.col is not the same as SELECT a.* FROM a WHERE col IN ( SELECT col FROM b ) , unless b.col is unique. However, this is the synonym for the first query: … Read more