Merged revisions 88334 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/branches/py3k

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  r88334 | antoine.pitrou | 2011-02-04 21:11:11 +0100 (ven., 04 févr. 2011) | 3 lines

  Mention that seek and tell over a TextIOWrapper can be very slow.
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Doc/library/io.rst

@@ -812,6 +812,8 @@ Text I/O over a binary storage (such as a file) is significantly slower than
 binary I/O over the same storage, because it implies conversions from
 unicode to binary data using a character codec.  This can become noticeable
 if you handle huge amounts of text data (for example very large log files).
+Also, :meth:`TextIOWrapper.tell` and :meth:`TextIOWrapper.seek` are both
+quite slow due to the reconstruction algorithm used.
 
 :class:`StringIO`, however, is a native in-memory unicode container and will
 exhibit similar speed to :class:`BytesIO`.