Re: Patch: use internal folder summary cache always

[Philip Van Hoof <spam pvanhoof be>]

Please retest after updating your checkout, and verify the performance
improvements in these commits:

http://tinymail.org/trac/tinymail/changeset/3216
http://tinymail.org/trac/tinymail/changeset/3215
http://tinymail.org/trac/tinymail/changeset/3214

I think those will solve your performance problem (local Maildir
folder's summaries where always re-created because the uids where never
found, because they never ended up in that hashtable, because the uid
was assigned after the item was put in the summary -- and therefore
after the item was inserted into the hashtable too --).


On Sun, 2007-12-30 at 19:31 +0100, Philip Van Hoof wrote:
> The very logic of this patch is wrong.
> 
> The function camel_folder_summary_prepare_hash and the function
> camel_folder_summary_kill_hash must be wrapped around the location where
> a lot of UID look-ups are going to be used.
> 
> You can't just let it create the hash always, as that will increase
> memory usage and force the implementation to always create hash keys
> too.
> 
> This will make only a few operations faster, but most other operations
> will be slower (and will consume more memory too).
> 
> Therefor, I reject this patch.
> 
> What would be useful is to know at what location the uid look-up takes
> place. Perhaps we can wrap that location's loop with the prepare and
> kill hash functions in stead?
> 
> What calling function appear in your profiler's trace above the uid
> look-up in camel-folder-summary.c?
> 
> Note that the new summary storage code (mytest7.tar.gz, posted on Thu
> this week to Tinymail's mailing list) copes with looking up using both
> sequence numbers and uids too.
> 
> Also note that if you can look-up by sequence number, that you don't
> need to create the hash-table with the current implementation.
> 
> So it's better to refactor the offending code to use sequence numbers.
> If that's really not possible, you can wrap the code with prepare and
> kill - hash.
> 
> 
> On Fri, 2007-12-21 at 19:53 +0100, Jose Dapena Paz wrote:
> > El vie, 21-12-2007 a las 10:46 +0100, Jose Dapena Paz escribió:
> > > 	This patch also includes some changes to make save_append operation
> > > work a bit better. Unfortunately, this is not enough as I'm getting
> > > heavy corruption (mainly with move to operation in pop folders). Then,
> > > it still needs more work, and that's why append is disabled now.
> > 
> > 	This new patch converts the hash lock into a recursive lock, and then,
> > I avoid the silly while hack.
> > 
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-- 
Philip Van Hoof, freelance software developer
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gnome: pvanhoof at gnome dot org 
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