Werk #7572: Avoid quadratic time complexity in buffer handling

Component Other components
Title Avoid quadratic time complexity in buffer handling
Date Feb 25, 2016
Checkmk Edition Checkmk Raw (CRE)
Checkmk Version 1.2.7i3
Level Prominent Change
Class Bug Fix
Compatibility Compatible - no manual interaction needed

The rrdcached used a naive algorithm for handling its write buffer, leading to quadratic time complexity: In an example at hand, more than 130GB of data was needlessly shuffled around when trying to fetch a small amount of data points. This algorithm has been replaced by one with amortized linear complexity, vastly improving performance for various rrdcached operations.

Fixed a few arbitrary length restrictions on the way.

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