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[3.6] bpo-34134: Advise to use imap or imap_unordered when handling long iterables. (gh-8324) #11674

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[3.6] bpo-34134: Advise to use imap or imap_unordered when handling long iterables. (gh-8324) #11674

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6 changes: 5 additions & 1 deletion Doc/library/multiprocessing.rst
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Expand Up @@ -2125,6 +2125,10 @@ with the :class:`Pool` class.
the process pool as separate tasks. The (approximate) size of these
chunks can be specified by setting *chunksize* to a positive integer.

Note that it may cause high memory usage for very long iterables. Consider
using :meth:`imap` or :meth:`imap_unordered` with explicit *chunksize*
option for better efficiency.

.. method:: map_async(func, iterable[, chunksize[, callback[, error_callback]]])

A variant of the :meth:`.map` method which returns a result object.
Expand All @@ -2143,7 +2147,7 @@ with the :class:`Pool` class.

.. method:: imap(func, iterable[, chunksize])

A lazier version of :meth:`map`.
A lazier version of :meth:`.map`.

The *chunksize* argument is the same as the one used by the :meth:`.map`
method. For very long iterables using a large value for *chunksize* can
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