[IronPython] Performance str.replace in Silverlight
Michael Foord
michael at voidspace.org.uk
Thu May 27 18:41:28 CEST 2010
Hey guys,
I just tracked down a really nasty performance bug in our Silverlight
application. It turned out that doing a simple string replace in a 400
character string was taking 700ms. As we actually do two replaces and
the text is usually substantially longer this was a real problem.
I fixed the problem by switching to explicitly calling the .NET
String.Replace instead of str.replace, so it looks like an IronPython
issue. It doesn't happen with *all* text, but it looks like non-ascii
exacerbates the problem.
The particular text that triggered it was:
Die Neuanlage einer Welle muss auch zu Einträgen in der Tabelle
dbo_tv_wellenwebsitesfirmenverbinder führen. Dabei werden die
Zuordnungen aus der Vorwelle bei der Neuanlage einer neuen Welle
einmalig übernommen. Jede Zeile der Vorwelle wird also kopiert und die
Kopie erhält die Welle_uniqueID der neuen Welle. Die Verbindung zwischen
Website_uniqueID <-> Firmen_uniqueID <-> FirmenAbrechnung_uniqueID
bleibt somit erhalten.
The replace code was:
text = text.replace('\r\n', '\n').replace('\r', '\n')
The fix was:
text = String.Replace(text, '\r\n', '\n')
text = String.Replace(text, '\r', '\n')
All the best,
Michael Foord
--
http://www.ironpythoninaction.com/
http://www.voidspace.org.uk/blog
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