thumbnail-spec: proposing nested thumbnail cache directories
talex5 at gmail.com
Fri Sep 7 11:02:28 PDT 2007
On Thu, 30 Aug 2007 12:06:10 +0200, Christian Neumair wrote:
> Dear xdg list,
> Over at GNOME land we have the problem that due to the huge size of the
> thumbnail directories, refreshing in-memory thumbnail readdir() caches
> takes very long.
> The caches are required as thumbnails are looked up for *every* file one
> opens with the file manager, so the cumulative performance impact is
> Alexander Larsson proposed to reduce this delay massively by using
> nested directories - git does that as well:
> The first two digits of the MD5 hash "4f831f...89" would be split apart,
> and used to create a subdirectory "4f". The thumbnail file corresponding
> to the specified example in this directory would then be named
> "831f...89.png". So the entire hash maps to the file "4f/831f...98.png"
> rather than "4f831f...98.png"
The problem with this is that to render one directory of images you need
to open a lot of thumbnails directories, evenly distributed. Also, it's a
hack to work-around a filesystem problem. A better scheme would be to
md5sum the name of the directory containing the image, e.g. thumbnailing
a directory containing 'dog.jpg' and 'cat.jpg' would create/access:
Thus you get all the images you need together in the cache. Also helps
with deleting/renaming directories.
This was suggested by Rasterman a while ago, IIRC. If we're going to
change the spec, I'd prefer to change to that.
Dr Thomas Leonard http://rox.sourceforge.net
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