Re: Modest/TinyMail problems (continue from the blog comments)

[Eero Tamminen <eero tamminen nokia com>]

Hi,

ext Philip Van Hoof wrote:
> There are also other solutions for handling really large folders of more
> than 15,000 items. The problem is not so much network bandwidth of the
> envelopes. The problem is rather that each 5000th item the complete
> summary storage file is rewritten on a relatively slow flash storage.
>
> That's a file of by that time 12 MB. If any application during that
> write causes a fsync() call, that'll indeed hang your device for several
> minutes.
>
> A solution for that is to either append instead of rewrite the file, or
> rewrite the summary storage solution to use multiple smaller mapped
> files. We have an experimental summary storage like that in our code,
> but it's currently disabled because we didn't want to release untested
> code in the device's Modest instance.

Anybody doing large amount of writes to JFFS2, should take a quick look
at this bug:
	https://bugs.maemo.org/show_bug.cgi?id=2615

Append is better than rewriting whole file or over/re-writing parts
of the file.  Churn for the JFFS2 content should in general be avoided.


	- Eero