[imp] large session entries in horde_sessionhandler

[Michael M Slusarz]

Quoting liam hoekenga <liamr at umich.edu>:

>
>> Right now, this is mandatory for IMP to work properly (and has been
>> throughout all IMP 4.x releases - this is not something that has been
>> recently added).  Search the mailing lists a year or two back for the
>> very long explanation I gave about why this is necessary (a search for
>> "embedded MIME parts" will probably return the results you need).
>> Quick explanation: caching rendered parts is the only way we currently
>> can pass embedded MIME part data to another page without having to
>> write hundreds of lines of rendering code in each IMP page.
>
> Can we safely reduce the cache size from 20 to a smaller number (10? 5?)

I think this should work (since the cache information will never be 
replaced until another message is viewed).

I will say that IMP caching code has been written with the idea that 
multiple multi-megabyte files are not opened in succession.  Others may 
argue with this assumption - but the simple fact is it is pretty much 
impossible with a web-based centralized mail server solution to produce 
a performance efficient solution if the userbase is opening up 
excessively large messages.  Internet mail was never designed to 
transfer large amounts of data.  If it is the local admin's choice to 
allow these excessively large messages, then that is their choice.  IMP 
will display these messages - just don't be surprised if it uses up a 
lot of resources to do it.

(as a final note, the rendered message is only cached if it is 
displayed onscreen or is a part of an embedded MIME message.  
THerefore, for the vast amount of messages, this shouldn't be as much 
of an issue since the large MIME parrts are hopefully are labeled as 
'attachment' rather than 'inline'.

michael

_______________________________________
Michael Slusarz [slusarz at curecanti.org]