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Conditional Variable vs Semaphore
... that a piece of code is atomic, put a lock around it. You could theoretically use a binary semaphore to do this, but that's a special case.
Semaphores and condition variables build on top of the mutual exclusion provide by locks and are used for providing synchronized access to shared resources. ...
SQL Server: Query fast, but slow from procedure
... the quoted answer did not solve the problem for me. The query still ran really slow from a stored procedure.
I found another answer here "Parameter Sniffing", Thanks Omnibuzz. Boils down to using "local Variables" in your stored procedure queries, but read the original for more understanding, it...
How do I count a JavaScript object's attributes? [duplicate]
...ry object in JavaScript derives from — includes many attributes automatically, and the exact set of attributes you get depends on the particular interpreter and what code has executed before yours. So, you somehow have to separate the ones you defined from those you got "for free."
Here's one way...
Inserting multiple rows in mysql
...
When loading a table from a text file, use LOAD DATA INFILE. This is usually 20 times faster than using INSERT statements.
Optimizing INSERT Statements
You can find more tips on how to speed up your insert statements on the link above.
...
How can I represent an 'Enum' in Python?
...y3, e.g. you'll need __order__ in python 2).
To use enum34, do $ pip install enum34
To use aenum, do $ pip install aenum
Installing enum (no numbers) will install a completely different and incompatible version.
from enum import Enum # for enum34, or the stdlib version
# from aenum import...
How to calculate a time difference in C++
...turns the CPU time consumed by the program. So if the program is run in parallel the time returned by the function would be the accumulated of the time spent on all CPUs, rather than the time elapsed cplusplus.com/reference/ctime/clock
– Ameer Jewdaki
Aug 3 '1...
Does Java casting introduce overhead? Why?
...casting, when you cast from a type to a wider type, which is done automatically and there is no overhead:
String s = "Cast";
Object o = s; // implicit casting
Explicit casting, when you go from a wider type to a more narrow one. For this case, you must explicitly use casting like that:
Object o ...
What is the default initialization of an array in Java?
... (whose decimal equivalent is 0).
When you create an array of something, all entries are also zeroed. So your array contains five zeros right after it is created by new.
Note (based on comments): The Java Virtual Machine is not required to zero out the underlying memory when allocating local va...
What's the difference between echo, print, and print_r in PHP?
...s, although such usage is rare; echo is slightly faster than print. (Personally, I always use echo, never print.)
var_dump prints out a detailed dump of a variable, including its type and the type of any sub-items (if it's an array or an object). print_r prints a variable in a more human-readable f...
Accessing private member variables from prototype-defined functions
...
No, there's no way to do it. That would essentially be scoping in reverse.
Methods defined inside the constructor have access to private variables because all functions have access to the scope in which they were defined.
Methods defined on a prototype are not defin...