Prefetch with short TTL?

[John Horne]

On Thu, 2023-02-16 at 09:50 +0100, George (Yorgos) Thessalonikefs via Unbound-
users wrote:
>
> What prefetch does for cached records is to try and refetch the record
> internally (the client still gets the fast cached answer) when a cached
> record is used for the answer and that record's TTL is at the last 10%
> of the original TTL.
> This hopefully will update the record in the background and future
> client requests will not notice any resolution delay.
> This works best for "popular" records since the prefetch logic needs a
> client query for a non-expired record.
>
> For a record with TTL 60 that means that when the remaining TTL <= 6 and
> a client asks for that record, Unbound will try to update the record in
> the background.
>
Sorry for the late reply. Thanks for that. We occasionally have a sort of spike
of requests for sites with low TTL values. I was just wondering if this caused
a problem for prefetching or not, given that 10% of the TTL may only be a few
seconds. It seems it is not a problem :-)


John.

>
> On 08/02/2023 23:09, John Horne via Unbound-users wrote:
> > Hello,
> >
> > Running Unbound 1.16.2, would someone explain what effect the prefetch
> > option
> > has with domains with a short TTL (typically 60 seconds) please?
> >
> >
> >
> > Thanks,
> >
> > John.
> >
> > --
> > John Horne | Senior Operations Analyst | Technology and Information
> > Services
> > University of Plymouth | Drake Circus | Plymouth | Devon | PL4 8AA | UK
> > ________________________________
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--
John Horne | Senior Operations Analyst | Technology and Information Services
University of Plymouth | Drake Circus | Plymouth | Devon | PL4 8AA | UK
________________________________
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This email and any files with it are confidential and intended solely for the use of the recipient to whom it is addressed. If you are not the intended recipient then copying, distribution or other use of the information contained is strictly prohibited and you should not rely on it. If you have received this email in error please let the sender know immediately and delete it from your system(s). Internet emails are not necessarily secure. While we take every care, University of Plymouth accepts no responsibility for viruses and it is your responsibility to scan emails and their attachments. University of Plymouth does not accept responsibility for any changes made after it was sent. Nothing in this email or its attachments constitutes an order for goods or services unless accompanied by an official order form.