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Database cluster and load balancing
What is database clustering? If you allow the same database to be on 2 different servers how do they keep the data between synchronized. And how does this differ from load balancing from a database server perspective?
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Python group by
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Python's built-in itertools module actually has a groupby function , but for that the elements to be grouped must first be sorted such that the elements to be grouped are contiguous in the list:
from operator import itemgetter
sortkeyfn = itemgetter(1)
input = [(...
How to write header row with csv.DictWriter?
...ion "functionality", I'd prefer to code it myself; that way you can report ALL "extras" with the keys and values, not just the first extra key. What is a real nuisance with DictWriter is that if you've verified the keys yourself as each dict was being built, you need to remember to use extrasaction=...
Closing WebSocket correctly (HTML5, Javascript)
...ink the connection is still open even when it's not.
The browser should really do this for you when you close or reload the page. However, you can make sure a close frame is sent by doing capturing the beforeunload event:
window.onbeforeunload = function() {
websocket.onclose = function () {};...
How to edit a node module installed via npm?
...go straight to the source.
If the changes affect functionality of the overall module, and may be useful to others, you may want to contribute to the original source on github and look for the change to be implemented.
If this is proprietary functionality that is needed, and would not help the deve...
Array slicing in Ruby: explanation for illogical behaviour (taken from Rubykoans.com)
...n Ruby Koans and I was struck by the following Ruby quirk that I found really unexplainable:
10 Answers
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C# version of java's synchronized keyword?
... be thread-safe. Use YAGNI: only apply thread-safety when you know you actually are going to use it (and test it).
For the method-level stuff, there is [MethodImpl]:
[MethodImpl(MethodImplOptions.Synchronized)]
public void SomeMethod() {/* code */}
This can also be used on accessors (properties ...
Appropriate datatype for holding percent values?
...mber of digits after the decimal separator?
– Boris Callens
Jun 15 '12 at 13:20
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@BorisCallens -...
Adding a new array element to a JSON object
...ve a JSON format object I read from a JSON file that I have in a variable called teamJSON, that looks like this:
6 Answers
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Explaining Apache ZooKeeper
...ersisted data is distributed between multiple nodes (this set of nodes is called an "ensemble") and one client connects to any of them (i.e., a specific "server"), migrating if one node fails; as long as a strict majority of nodes are working, the ensemble of ZooKeeper nodes is alive. In particular,...