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What exactly are “spin-locks”?
...ritical sections etc), operating system puts your thread in the WAIT state and preempts it by scheduling other threads on the same core. This has a performance penalty if the wait time is really short, because your thread now has to wait for a preemption to receive CPU time again.
Besides, kernel ob...
How to print out more than 20 items (documents) in MongoDB's shell?
... @LukaszWiktor yes, you can create a $HOME/.mongorc.js file and put that shellBatchSize setting in there. mine has the query batch size setting and rs.slaveOk() enabled. it's usage is also slightly different when using --eval via commandline. see: docs.mongodb.com/manual/mongo/#mongor...
Is there a way to keep Hudson / Jenkins configuration files in source control?
I am new to Hudson / Jenkins and was wondering if there is a way to check in Hudson's configuration files to source control.
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In a django model custom save() method, how should you identify a new object?
...exes on other fields). In that case, you could still have a new record in hand, but be unable to save it.
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Returning the product of a list
...sing lambda:
from operator import mul
reduce(mul, list, 1)
it is better and faster. With python 2.7.5
from operator import mul
import numpy as np
import numexpr as ne
# from functools import reduce # python3 compatibility
a = range(1, 101)
%timeit reduce(lambda x, y: x * y, a) # (1)
%timeit r...
How to remove all the occurrences of a char in c++ string
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Basically, replace replaces a character with another and '' is not a character. What you're looking for is erase.
See this question which answers the same problem. In your case:
#include <algorithm>
str.erase(std::remove(str.begin(), str.end(), 'a'), str.end());
Or us...
Is it possible for a computer to “learn” a regular expression by user-provided examples?
...ton, it is possible to learn some regular expressions by a program. Kearns and Valiant show some cases where it is not possible to learn a finite automaton. A related problem is learning hidden Markov Models, which are probabilistic automata that can describe a character sequence. Note that most mod...
Connection timeout for SQL server
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Yes, you could append ;Connection Timeout=30 to your connection string and specify the value you wish.
The timeout value set in the Connection Timeout property is a time expressed in seconds. If this property isn't set, the timeout value for the connection is the default value (15 seconds).
Mo...
Physical vs. logical / soft delete of database record?
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Advantages are that you keep the history (good for auditing) and you don't have to worry about cascading a delete through various other tables in the database that reference the row you are deleting. Disadvantage is that you have to code any reporting/display methods to take the flag ...
How do I partially update an object in MongoDB so the new object will overlay / merge with the exist
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If I understand the question correctly, you want to update a document with the contents of another document, but only the fields that are not already present, and completely ignore the fields that are already set (even if to another valu...