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Why does direction of index matter in MongoDB?
...ormally the performance hit is negligible (especially compared to gains in read performance), but that doesn't mean that we can't be smart about creating our indexes.
How Indexes
Identifying what group of fields should be indexed together is about understanding the queries that you are running. The ...
Declaring variables inside loops, good practice or bad practice?
...kes your code safer, with less states (i.e. variables) to worry about when reading other parts of the code.
This is true even outside of an if(){...} block. Typically, instead of :
int result;
(...)
result = f1();
if (result) then { (...) }
(...)
result = f2();
if (resu...
Data Modeling with Kafka? Topics and Partitions
...is to first partition by say :user-id, and then to re-partition by :viewed ready for the next phase of processing.
On topic names - an obvious one here would be events or user-events. To be more specific you could go with with events-by-user-id and/or events-by-viewed.
...
Traits in PHP – any real world examples/best practices? [closed]
... error (demo). Likewise, any methods declared in the trait that are also already declared in the using class will not get copied into the class, e.g.
trait T {
public function foo() {
return 1;
}
}
class A {
use T;
public function foo() {
return 2;
}
}
$a = new A;
echo $a->...
performSelector may cause a leak because its selector is unknown
...void *)imp;
func(_controller, selector);
Or more tersely (though hard to read & without the guard):
SEL selector = NSSelectorFromString(@"someMethod");
((void (*)(id, SEL))[_controller methodForSelector:selector])(_controller, selector);
Explanation
What's going on here is you're asking th...
Chaining multiple filter() in Django, is this a bug?
...inventory__user__profile__country='BR')
And if you want to use OR please read: https://docs.djangoproject.com/en/dev/topics/db/queries/#complex-lookups-with-q-objects
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What methods of ‘clearfix’ can I use?
...
Read more about hasLayout at stackoverflow.com/questions/1794350/what-is-haslayout. I think of it as synonymous with establishing a new block formatting context. Elements that do this are essentially responsible for the layou...
Difference between std::system_clock and std::steady_clock?
...td::to_string(GetLastError()));
}
};
For Linux it is even easier. Just read the man page of clock_gettime and modify the code above.
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Can JSON start with “[”?
From what I can read on json.org , all JSON strings should start with { (curly brace), and [ characters (square brackets) represent an array element in JSON.
...
CSS: fixed position on x-axis but not y?
...
This is an old thread but CSS3 has a solution.
position: sticky;
Have a look at this blog post.
Demonstration:
And this documentation.
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