From b47f2f5b907732d80b164f1f361ae39da94a3fa6 Mon Sep 17 00:00:00 2001 From: Nick Pope Date: Fri, 22 Jul 2022 21:08:10 +0100 Subject: Fixed #33865 -- Optimized LimitedStream wrapper. The current implementation of LimitedStream is slow because .read() performs an extra copy into a buffer and .readline() performs two extra copies. The stream being wrapped is already typically a BytesIO object so this is unnecessary. This implementation has largely been untouched for 12 years and, inspired by a simpler implementation in werkzeug, it was possible to achieve the following performance improvement: LimitedStream.read() (single line): Mean +- std dev: [bench_limitedstream-main] 286 ns +- 6 ns -> [bench_limitedstream-patch] 227 ns +- 6 ns: 1.26x faster LimitedStream.readline() (single line): Mean +- std dev: [bench_limitedstream-main] 507 ns +- 11 ns -> [bench_limitedstream-patch] 232 ns +- 8 ns: 2.18x faster LimitedStream.read(8192) (single line): Mean +- std dev: [bench_limitedstream-main] 360 ns +- 8 ns -> [bench_limitedstream-patch] 297 ns +- 6 ns: 1.21x faster LimitedStream.readline(8192) (single line): Mean +- std dev: [bench_limitedstream-main] 602 ns +- 10 ns -> [bench_limitedstream-patch] 305 ns +- 10 ns: 1.98x faster LimitedStream.read() (multiple lines): Mean +- std dev: [bench_limitedstream-main] 290 ns +- 5 ns -> [bench_limitedstream-patch] 236 ns +- 6 ns: 1.23x faster LimitedStream.readline() (multiple lines): Mean +- std dev: [bench_limitedstream-main] 517 ns +- 19 ns -> [bench_limitedstream-patch] 239 ns +- 7 ns: 2.16x faster LimitedStream.read(8192) (multiple lines): Mean +- std dev: [bench_limitedstream-main] 363 ns +- 8 ns -> [bench_limitedstream-patch] 311 ns +- 11 ns: 1.17x faster LimitedStream.readline(8192) (multiple lines): Mean +- std dev: [bench_limitedstream-main] 601 ns +- 12 ns -> [bench_limitedstream-patch] 308 ns +- 7 ns: 1.95x faster Geometric mean: 1.59x faster --- docs/releases/4.2.txt | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'docs') diff --git a/docs/releases/4.2.txt b/docs/releases/4.2.txt index 39235aa224..68392161e3 100644 --- a/docs/releases/4.2.txt +++ b/docs/releases/4.2.txt @@ -523,6 +523,10 @@ Miscellaneous .. _`redis-py`: https://pypi.org/project/redis/ +* Manually instantiated ``WSGIRequest`` objects must be provided a file-like + object for ``wsgi.input``. Previously, Django was more lax than the expected + behavior as specified by the WSGI specification. + .. _deprecated-features-4.2: Features deprecated in 4.2 -- cgit v1.3