Re: Sequential vs. random values - number of pages in B-tree

Hi,

>What's the reason that postgres needs more index pages to store random
>data
>than sequential ones?

I assume that is because B-Tree is self-balanced tree, so it needs to be
rebalanced after each insertion.
Random insertions may go to the head of index where no space left leading to
huge data moving.
https://en.wikipedia.org/wiki/B-tree#Insertions_and_deletions



Ilya Kazakevich

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