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Re: (ITS#3851) Berkeley DB Scalability Patch

--On Friday, July 15, 2005 6:57 PM -0700 Quanah Gibson-Mount 
<quanah@symas.com> wrote:
> Hi Jong,
> The second test looks good.
> Without patch:
> 630.304 ops/second
> 182.671 mod/second
> 447.632 searches/second
> With patch:
> 632.156 ops/second
> 183.216 mod/second
> 448.941 searches/second
> So a definite (though slight in my small database case) improvement.
> Yeah. :)

Hi Jong,

I'm curious if you have tested this patch on DB's with a large number of 
indices.  I put together a 100K entry DB (I unfortunately do not have 12GB 
RAM machines at my disposal) with 21 indices in it:

index   default eq
index   objectClass
index   uid
index   departmentNumber
index   cn              eq,sub,approx
index   sn              eq,sub,approx
index   l
index   ou
index   telephonenumber eq,sub
index   userpassword
index   givenName       eq,sub,approx
index   mail
index   carLicense
index   employeeType
index   homephone       eq,sub
index   mobile  eq,sub
index   pager   eq,sub
index   o
index   roomNumber
index   preferredLanguage
index   postalCode
index   st

I then tested the difference in load times with and without your DB 
scalability patch.  The effect I saw of having a large set of indices is 
that the DB scalability patch does not perform as well as the normal BDB 

Results w/o patch:
538.67u 7.76s 9:13.34 98.7%
537.08u 7.69s 9:12.05 98.6%
535.90u 8.17s 9:10.99 98.7%

Results w/ patch:
726.48u 13.03s 14:41.07 83.9%
727.89u 12.04s 14:37.65 84.3%
727.35u 12.06s 14:39.21 84.0%

One thing immediately evident is that the CPU usage drops a good 14-15% 
than without the patch, with a corresponding 1/3 increase in total time to 
load the database.

Have you done any testing of your patch on large scale DB's with a good 
number of indices?


Quanah Gibson-Mount
Product Engineer
Symas Corporation
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