about "query time" (caching)

[Reindl Harald]

Am 20.09.2016 um 00:12 schrieb Pol Hallen:
>> In the third case, the A records had expired from the cache (since the
>> TTL on those records is 300 seconds = 5 minutes), so your resolver
>> needed to fetch a fresh set from the yahoo.it nameservers -- the NS
>> records of which were most likely cached from the first lookup -- but
>> it didn't need to follow the referral chain all of the way down from
>> the root. 19 msec.
>
> thanks Kevin, now it's clear
>
> is there a way to keep update cache of queries users will do?

not sure hwat you mean but likely 
https://kb.isc.org/article/AA-01315/0/prefetch-performance-in-BIND-9.10.html