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Technically, why are processes in Erlang more efficient than OS threads?
... registers, address space mapping, etc.).
Erlang processes use dynamically allocated stacks, which start very small and grow as necessary. This permits the spawning of many thousands — even millions — of Erlang processes without sucking up all available RAM.
Erlang used to be single-threaded, me...
How to debug Lock wait timeout exceeded on MySQL?
...---------------
BUFFER POOL AND MEMORY
----------------------
Total memory allocated 18909316674; in additional pool allocated 1048576
Dictionary memory allocated 2019632
Buffer pool size 1048576
Free buffers 175763
Database pages 837653
Modified db pages 6
Pending reads 0
Pending write...
Amazon EC2, mysql aborting start because InnoDB: mmap (x bytes) failed; errno 12
...e enough (512M) memory for the InnoDB buffer pool:
Fatal error: cannot allocate memory for the buffer pool
That begs three questions:
How much memory is on your instance? Should there be enough memory to accommodate the 512M InnoDB is trying to grab for the buffer pool, plus everything else...
How long is the SHA256 hash?
...
varchar also doesn’t allocate space unless its used, unlike char it allocates the number of amount of total characters allowed regardless if there is data filling it.
– Xenland
Feb 11 '13 at 16:44
...
How to repeat a string a variable number of times in C++?
...ster implementation, the idea is to minimise copying operations and memory allocations by first exponentially growing the string:
#include <string>
#include <cstddef>
std::string repeat(std::string str, const std::size_t n)
{
if (n == 0) {
str.clear();
str.shrink_to...
Invalid argument supplied for foreach()
...ue)
{
...
}
}
The reason for my preference is it doesn't allocate an empty array when you've got nothing to begin with anyway.
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C++ performance vs. Java/C#
... lot of optimizations that just aren't safe.
Also Java and C# can do heap allocations more efficiently than C++ because the layer of abstraction between the garbage collector and your code allows it to do all of its heap compression at once (a fairly expensive operation).
Now I can't speak for Jav...
“INSERT IGNORE” vs “INSERT … ON DUPLICATE KEY UPDATE”
...ly, which has some unexpected side effects:
A new auto-increment ID is allocated.
Dependent rows with foreign keys may be deleted (if you use cascading foreign keys) or else prevent the REPLACE.
Triggers that fire on DELETE are executed unnecessarily.
Side effects are propagated to replicas too....
How to convert NSDate into unix timestamp iphone sdk?
...TimeStamp
{
NSDateFormatter *objDateformat = [[NSDateFormatter alloc] init];
[objDateformat setDateFormat:@"yyyy-MM-dd"];
NSString *strTime = [objDateformat stringFromDate:[NSDate date]];
NSString *strUTCTime = [self GetUTCDateTimeFromLocalTime:strTime];//Yo...
The Definitive C Book Guide and List
...uctures in C, such as lists, sets, exceptions, string manipulation, memory allocators, and more. Basically, Hanson took all the code he'd written as part of building Icon and lcc and pulled out the best bits in a form that other people could reuse for their own projects. It's a model of good C progr...