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Diffstat (limited to 'Misc/NEWS.d/next/Library/2017-11-10-00-05-08.bpo-31993.-OMNg8.rst')
| -rw-r--r-- | Misc/NEWS.d/next/Library/2017-11-10-00-05-08.bpo-31993.-OMNg8.rst | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/Misc/NEWS.d/next/Library/2017-11-10-00-05-08.bpo-31993.-OMNg8.rst b/Misc/NEWS.d/next/Library/2017-11-10-00-05-08.bpo-31993.-OMNg8.rst new file mode 100644 index 0000000..b453e21 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2017-11-10-00-05-08.bpo-31993.-OMNg8.rst @@ -0,0 +1,14 @@ +The picklers do no longer allocate temporary memory when dumping large +``bytes`` and ``str`` objects into a file object. Instead the data is +directly streamed into the underlying file object. + +Previously the C implementation would buffer all content and issue a +single call to ``file.write`` at the end of the dump. With protocol 4 +this behavior has changed to issue one call to ``file.write`` per frame. + +The Python pickler with protocol 4 now dumps each frame content as a +memoryview to an IOBytes instance that is never reused and the +memoryview is no longer released after the call to write. This makes it +possible for the file object to delay access to the memoryview of +previous frames without forcing any additional memory copy as was +already possible with the C pickler. |