bpo-34134: Advise to use imap or imap_unordered when handling long iterables. (gh-8324)
diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst
index a778159..987a0d5 100644
--- a/Doc/library/multiprocessing.rst
+++ b/Doc/library/multiprocessing.rst
@@ -2157,6 +2157,10 @@
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.
@@ -2175,7 +2179,7 @@
.. 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