From dc9dd0d3401243144384f7a5e54c731edaaf9d7e Mon Sep 17 00:00:00 2001 From: Nadeem Vawda Date: Mon, 2 Jan 2012 02:24:20 +0200 Subject: [PATCH] Add note on memory usage to LZMACompressor doc. --- Doc/library/lzma.rst | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/Doc/library/lzma.rst b/Doc/library/lzma.rst index 4e6db15a74..3941ec18d0 100644 --- a/Doc/library/lzma.rst +++ b/Doc/library/lzma.rst @@ -120,8 +120,16 @@ Compressing and decompressing data in memory ``9`` (inclusive), optionally OR-ed with the constant :const:`PRESET_EXTREME`. If neither *preset* nor *filters* are given, the default behavior is to use :const:`PRESET_DEFAULT` (preset level ``6``). - Higher presets produce smaller output, but make compression more CPU- and - memory-intensive, and also increase the memory required for decompression. + Higher presets produce smaller output, but make the compression process + slower. + + .. note:: + + In addition to being more CPU-intensive, compression with higher presets + also requires much more memory (and produces output that needs more memory + to decompress). With preset ``9`` for example, the overhead for an + :class:`LZMACompressor` object can be as high as 800MiB. For this reason, + it is generally best to stick with the default preset. The *filters* argument (if provided) should be a filter chain specifier. See :ref:`filter-chain-specs` for details. -- 2.49.0