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What is the recommended approach towards multi-tenant databases in MongoDB?
...decided not to have a database per
customer because of the way MongoDB
allocates its data files. Each
database uses it’s own set of files:
The first file for a database is
dbname.0, then dbname.1, etc. dbname.0
will be 64MB, dbname.1 128MB, etc., up
to 2GB. Once the fil...
Design patterns or best practices for shell scripts [closed]
...do object oriented programming, unless you build a quite complex system of allocation of objects (I thought about that. it's feasible, but insane).
In practice, you can however do "Singleton oriented programming": you have one instance of each object, and only one.
What I do is: i define an object ...
Does const mean thread-safe in C++11?
...too artificial, you could mentally replace int by a very large dynamically allocated integer which is inherently non thread-safe and for which multiplications are extremely costly.]
The member-function area is no longer thread-safe, it is doing writes now and is not internally synchronized. Is it a ...
Uses for Optional
...) { return Optional.ofNullable(parent); }. This looks expensive because it allocates an Optional every time! But if the caller unpacks it immediately, the object is extremely short-lived and is never promoted out of eden space. It might possibly even be eliminated by the JIT's escape analysis. The b...
Learning Python from Ruby; Differences and Similarities
...ifferent between the two languages. Here, the problem is that you want to allocate some resource (open a file, obtain a database cursor, etc), perform some arbitrary operation on it, and then close it in a safe manner even if an exception occurs.
In Ruby, because blocks are so easy to use (see #9)...
What is recursion and when should I use it?
... However, the real problem is in step #1. When many programs start, they allocate a single chunk of memory for their stack, and when they run out of that memory (often, but not always due to recursion), the program crashes due to a stack overflow.
So in these languages recursion is slower and it ...
Should I return a Collection or a Stream?
...ually two costs here: the cost of storing values in the collection (memory allocation and copying) and also the cost of creating the values in the first place. The latter cost can often be reduced or avoided by taking advantage of a Stream's laziness-seeking behavior. A good example of this are the ...
C++11 rvalues and move semantics confusion (return statement)
..., a new vector is actually constructed in the copy constructor and data is allocated, but the bulk of the data array is only copied by copying the pointer (essentially). The copy elision avoids 100% of all copies.
– Mark Lakata
Dec 11 '14 at 1:26
...
When to use symbols instead of strings in Ruby?
...utput, you should go with strings, even if it appears more than once, even allocating two different objects in memory.
Here's the reasoning:
Printing the symbols will be slower than printing strings because they are cast to strings.
Having lots of different symbols will increase the overall mem...
Why can templates only be implemented in the header file?
...at would add overhead such as boxing, needing to pass function pointers to allocators and constructors, etc. The intention of C++ templates is to avoid having to write nearly identical class MyClass_int, class MyClass_float, etc, but to still be able to end up with compiled code that is mostly as if...