[Unbound-users] Prefetch

Luo Ce luoce at cnnic.cn
Wed Dec 7 07:24:03 UTC 2011

Hi Scott,

In the file msgreply.h there is a marco definition below:

/** calculate the prefetch TTL as 90% of original. Calculation
 * without numerical overflow (uin32_t) */
#define PREFETCH_TTL_CALC(ttl) ((ttl) - (ttl)/10)

If you only want to change the prefetch calculation, modify the marco above
will work.


Luo Ce

-----Original Message-----
From: unbound-users-bounces at NLnetLabs.nl
[mailto:unbound-users-bounces at NLnetLabs.nl] On Behalf Of Scott A. Johnson
Sent: Wednesday, December 07, 2011 2:09 PM
To: unbound-users at unbound.net
Subject: [Unbound-users] Prefetch

My understanding of setting prefetch to "yes" in unbound.conf will
cause unbound, after replying with the answer to a quarry, to re-fetch
the requested record if the TTL is 10% or lower of the record's normal
TTL so as to be ready for the next request for the same record.

Is this how the prefetch setting is supposed to work?  If so, I now
have another question..... where is this 10% calculation in the code?
I looked through unbound.c and a couple other files in the SVN
repository but couldn't find the code.  I want to make a few changes
to the calculation and recompile for my system.  Any pointers on where
I can find this (calculation in the) code?



Scott A. Johnson
scott.a.johnson at gmail.com
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