[New-bugs-announce] [issue23266] Faster implementation to collapse non-consecutive ip-addresses

[Markus]

New submission from Markus:

I found the code used to collapse addresses to be very slow on a large number (64k) of island addresses which are not collapseable.

The code at
https://github.com/python/cpython/blob/0f164ccc85ff055a32d11ad00017eff768a79625/Lib/ipaddress.py#L349
was found to be guilty, especially the index lookup.
The patch changes the code to discard the index lookup and have _find_address_range return the number of items consumed.
That way the set operation to dedup the addresses can be dropped as well.

Numbers from the testrig I adapted from http://bugs.python.org/issue20826 with 8k non-consecutive addresses:

Execution time: 0.6893927365541458 seconds
vs.
Execution time: 12.116527611762285 seconds


MfG
Markus Kötter

----------
components: Library (Lib)
files: ipaddress_collapse_non_consecutive_performance.diff
keywords: patch
messages: 234239
nosy: cmn
priority: normal
severity: normal
status: open
title: Faster implementation to collapse non-consecutive ip-addresses
type: performance
versions: Python 3.5
Added file: http://bugs.python.org/file37762/ipaddress_collapse_non_consecutive_performance.diff

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<http://bugs.python.org/issue23266>
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