Message 245128 - Python tracker

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In-reply-to
Author	Robert Haschke
Recipients	Robert Haschke
Date	2015年06月10日.13:29:15
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1433942956.66.0.599460998017.issue24424@psf.upfronthosting.co.za>

Content
Node.insertBefore() has a serious performance issue: Using self.childNodes.index(refChild) it searches for the correct index in childNodes where the newChild should be inserted. However, index() is linear in time w.r.t. the size of childNodes. Hence, if there are many children, runtime dramatically increases. Adding a simple caching mechanism (caching the previously used reference) I was able to reduce runtime in my particular case from 16s to 1.6s, i.e. a factor of 10!

Content

Node.insertBefore() has a serious performance issue:
Using self.childNodes.index(refChild) it searches for the correct index in childNodes where the newChild should be inserted.
However, index() is linear in time w.r.t. the size of childNodes.
Hence, if there are many children, runtime dramatically increases.
Adding a simple caching mechanism (caching the previously used reference)
I was able to reduce runtime in my particular case from 16s to 1.6s, i.e. a factor of 10!

History
Date	User	Action	Args
2015年06月10日 13:29:16	Robert Haschke	set	recipients: + Robert Haschke
2015年06月10日 13:29:16	Robert Haschke	set	messageid: <1433942956.66.0.599460998017.issue24424@psf.upfronthosting.co.za>
2015年06月10日 13:29:16	Robert Haschke	link	issue24424 messages
2015年06月10日 13:29:16	Robert Haschke	create

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