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Memcache(d) vs. Varnish for speeding up 3 tier web architecture

I'm trying to speed up my benchmark (3 tier web architecture), and I have some general questions related to Memcache(d) and Varnish. ...
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Paperclip::Errors::MissingRequiredValidatorError with Rails 4

...nt_file_name :image, :matches => [/png\Z/, /jpe?g\Z/, /gif\Z/] Option 3: Do not validate If for some crazy reason (can be valid but I cannot think of one right now), you do not wish to add any content_type validation and allow people to spoof Content-Types and receive data you weren't expectin...
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How can you hide database output in Rails console?

In newer version of Rails, I'm guessing from 3 up, database queries are output to the console. This is useful most of the time, but how can you hide it when you do not want to see it? ...
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How to get values from IGrouping

... codidact.com 14.6k44 gold badges6868 silver badges7373 bronze badges answered Dec 15 '11 at 13:56 Matt SmithMatt Smith 15.4k66 go...
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What does .SD stand for in data.table in R

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Merge a Branch into Trunk

... GreenAsJade 13.5k99 gold badges5353 silver badges8787 bronze badges answered Oct 3 '11 at 18:02 blahdiblahblahdibl...
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Finding the index of elements based on a condition using python list comprehension

... of a list. >>> import numpy >>> a = numpy.array([1, 2, 3, 1, 2, 3]) >>> a array([1, 2, 3, 1, 2, 3]) >>> numpy.where(a > 2) (array([2, 5]),) >>> a > 2 array([False, False, True, False, False, True], dtype=bool) >>> a[numpy.where(a > 2...
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Difference between . and : in Lua

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Slicing of a NumPy 2d array, or how do I extract an mxm submatrix from an nxn array (n>m)?

... As Sven mentioned, x[[[0],[2]],[1,3]] will give back the 0 and 2 rows that match with the 1 and 3 columns while x[[0,2],[1,3]] will return the values x[0,1] and x[2,3] in an array. There is a helpful function for doing the first example I gave, numpy.ix_. Y...
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dplyr: “Error in n(): function should not be called directly”

... Michael Bellhouse 1,39711 gold badge1111 silver badges2525 bronze badges answered Apr 2 '14 at 3:59 mnelmnel ...