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Fix Windows redo-ocr performance regression; drop pdfminer BUFSIZ workaround (#1706)

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Since v16.4.3, OCRmyPDF forced pdfminer's read buffer to 256 MiB to work
around a pdfminer bug that mishandled tokens split across the buffer
boundary (gh #1361). On Windows this caused a severe performance
regression (gh #1662): CPython's BufferedReader.read(n) eagerly allocates
an n-byte buffer on every read, so pdfminer's thousands of seek+read
cycles each paid a ~30 ms 256 MiB allocation (this allocation is lazy and
effectively free on Linux). For a typical PDF the "Scanning contents"
phase went from ~5s on Linux to ~60s on Windows.

The underlying pdfminer bug was fixed upstream in pdfminer.six 20250327
(pdfminer/pdfminer.six#1030), with a follow-up for tokens split across
streams in 20260107 (pdfminer/pdfminer.six#1158). Remove the monkeypatch
entirely and raise the minimum pdfminer.six to 20260107 so we rely on the
upstream fix instead.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
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jbarlow
2026-06-18 10:34:20 -07:00
committed by GitHub
co-authored by Claude Opus 4.8
parent 334918d0f7
commit e6fab76918
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docs/releasenotes/version17.md
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# v17
## v17.7.1
- Fixed a severe, Windows-specific performance regression in the "Scanning
contents" phase, most visible with `--redo-ocr` ({issue}`1662`). Since
v16.4.3, OCRmyPDF forced pdfminer's read buffer to 256 MiB to work around a
pdfminer bug that mishandled tokens split across the buffer boundary
({issue}`1361`). On Windows, CPython's `BufferedReader.read()` eagerly
allocates a buffer of the requested size on every read, so the oversized
buffer made each of pdfminer's thousands of reads cost tens of milliseconds
(this allocation is lazy, and effectively free, on Linux). The underlying
pdfminer bug was fixed upstream in pdfminer.six 20250327
([#1030](https://github.com/pdfminer/pdfminer.six/pull/1030)), with a
follow-up for tokens split across streams in 20260107
([#1158](https://github.com/pdfminer/pdfminer.six/pull/1158)), so the
workaround has been removed and the minimum pdfminer.six version raised to
20260107.
## v17.7.0
- The Docker images now run as a non-root user (`app`, uid/gid 1000) by default