Werk #7572: Avoid quadratic time complexity in buffer handling

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

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 This algorithm has been replaced by one with amortized linear complexity, vastly improving performance for various rrdcached operations.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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