[Zope-dev] OFS.Image.File thrashes ZODB Connection Cache

[Tres Seaver]

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In current Zope2 (ZODB <= 3.7.2), the OFS.Image.File object's
'index_html' shows particularly obnoxious tendency to destroy locality
of reference in the connection cache.  I wrote the problem up as a
Launchpad bug:

 https://bugs.launchpad.net/zope2/+bug/157245

That bug report also sketches a solution: I have checked in an initial
stab at implementing it on a branch in SVN:

 http://svn.zope.org/Sandbox/tseaver/no_pdata_in_cache_dammit/

Thoughts?

I realize that a not-yet-released Zope2 which uses the ZODB 3.8 blob
storage stuff might not have this problem (assuming that OFS.Image.File
is updated to take advantage of blobs).  Also, as I note in the issue,
the fix doesn't help the thrashing of the disk-based cache used by ZEO
client connections.



Tres.
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Tres Seaver          +1 540-429-0999          tseaver at palladion.com
Palladion Software   "Excellence by Design"    http://palladion.com
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