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From Kiran Ayyagari <kayyag...@apache.org>
Subject Re: [Mavibot Partition] Cache experiments
Date Mon, 02 Dec 2013 13:51:45 GMT
On Mon, Dec 2, 2013 at 6:28 PM, Emmanuel L├ęcharny <elecharny@gmail.com>wrote:

> Hi,
>
> now that the Mavibt partition is working, I was able to profile the
> server on a search operation. I do a test where I inject 10 000 entries,
> and do 400 000 random searches accross those 10 000 entries.
>
> At first, I realized that the EntryCache was initialized to accept only
> 1 - yes, *one* - entry. You bet that we get a lot of cache misses !
> Fixing that lead to a 10% spedup improvement. The time we spare is the
> cost of finding an entry browsing a BTree, even if all the BTree pages
> are cached (whch s not likely to be a good idea : better favor a huge
> entry cache than a huge page cache, the benefit is immediate for a lower
> memory cost...)
>
> Second run : the alias cache was added, and this time, I got some
> improvement (the last time I added the alias cache was due to fail,
> because, again, the number aliases stored in this cache was configured
> to ... 1 !). Another 10% win.
>
> Third run : now, I'm caching the ParentIdAndRdn elements, as we need to
> access them to reconstruct the DN for each entry. Obviously, the parent
> RDN will always be the same... Gain : another 10%.
>
> I'm now able to do around 15 000 searches per second on my laptop,
> against around 11 000 before (note : this is a test done with no network
> involved).
>
> I will run them on my Mac as soon as you commit, I think server will
do a little better cause this is a new machine.

>
> Not bad...
>
> Althouh the cache configuation now requires a lot of love in order to be
> used for real, but this is not something big to do...
>
> More to come after the next profiling session !
>
> --
> Regards,
> Cordialement,
> Emmanuel L├ęcharny
> www.iktek.com
>
>


-- 
Kiran Ayyagari
http://keydap.com

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