[PATCH] BDB speedup (was: FSFS speedup)

[Branko Čibej <br...@xbc.nu>]

Peter N. Lundblad wrote:

>OK. Here we go. On my tests it is a big speedup. I tested on FSFS with and
>without xdelta when the dump was loaded. It seems like we win a lot even
>if vdelta was used to create the repo. Anyway, feel free to fill in the
>missing row above:-)
>  
>
Well, I've done something similar to the BDB combiner, except that it 
only pre-expands windows that are truly self-compressed. At the moment, 
this makes hardly any difference. However, it paves the way for storing 
fulltexts as self-compressed vdeltas in BDB, too, just as FSFS does it. 
This could significantly reduce the size of BDB repositories, especially 
where there are many active branches.

[[[
Treat self-compressed delta windows as virutal fulltexts in the 
delta combiner; expand them first instead of combining them with
the rest of the delta chain.

* subversion/libsvn_fs_base/reps-strings.c (compose_handler_baton):
   New member source_buf; holds expanded window data.
  (compose_handler): When handling a self-compressed window, expand
   it instead of combining it with the existing (combined) window.
  (rep_undeltify_range): If available, use the expanded window from
   the baton instead of the fulltext. Remove empty_buf.
]]]


-- Brane