performance Archives - Page 2 of 3

performance, Programming

IT Nursery

postgresql COUNT(DISTINCT …) very slow

I have a very simple SQL query: SELECT COUNT(DISTINCT x) FROM table; My table has about 1.5 million rows. This query is running ...

May 28, 2022
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performance, Programming

IT Nursery

Why would introducing useless MOV instructions speed up a tight loop in x86_64 assembly?

Background: While optimizing some Pascal code with embedded assembly language, I noticed an unnecessary MOV instruction, and removed it. To my surprise, removing ...

May 26, 2022
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How to find the kth largest element in an unsorted array of length n in O(n)?

I believe there’s a way to find the kth largest element in an unsorted array of length n in O(n). Or perhaps it’s ...

May 25, 2022
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How does Go compile so quickly?

I’ve Googled and poked around the Go website, but I can’t find an explanation for Go’s extraordinary build times. Are they products of ...

May 23, 2022
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Recursion or Iteration?

Is there a performance hit if we use a loop instead of recursion or vice versa in algorithms where both can serve the ...

May 22, 2022
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Why JSF calls getters multiple times

Let’s say I specify an outputText component like this: <h:outputText value="#{ManagedBean.someProperty}"/> If I print a log message when the getter for someProperty is ...

May 20, 2022
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Is it safe to shallow clone with –depth 1, create commits, and pull updates again?

The --depth 1 option in git clone: Create a shallow clone with a history truncated to the specified number of revisions. A shallow ...

May 17, 2022
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Why is Haskell (GHC) so darn fast?

Haskell (with the GHC compiler) is a lot faster than you’d expect. Used correctly, it can get close-ish to low-level languages. (A favorite ...

May 15, 2022
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What’s the most efficient way to test if two ranges overlap?

Given two inclusive ranges [x1:x2] and...

May 14, 2022
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Is recursion ever faster than looping?

I know that recursion is sometimes a lot cleaner than looping, and I’m not asking anything about when I should use recursion over ...

May 13, 2022
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