Re: serve-expired seems to break flush_zone
On 2018-04-09 03:40 AM, W.C.A. Wijngaards wrote:
Hi Marc,
I can confirm that the patch fixes my test case (in 1.6.7).
The documentation update also looks good.
Thanks for the quick response!
M.
On 06/04/18 17:05, Marc Branchaud wrote:
On 2018-04-06 02:47 AM, W.C.A. Wijngaards via Unbound-users wrote:
Hi Marc,
On 04/04/18 20:29, Marc Branchaud via Unbound-users wrote:
Hi all,
I have a simple forward-everything setup with serve-expired enabled:
server:
serve-expired: yes
forward-zone:
name: .
forward-addr: X.X.X.X
If I use "flush_zone ." to clear the cache, I still get cache hits for
supposedly-absent entries (dump_cache shows that the cache is empty).
When I turn serve-expired off, "flush_zone ." results in cache misses
for flushed entries.
With serve-expired on, I can only seem to force a cache miss by
explicitly flushing a name (e.g. "flush google.com"). I really want to
clear the entire cache, though.
Is this an intended effect of serve-expired, or is it a bug?
Right now this is the design of flush-zone, it iterates over the cache
contents. And it sets every element of the flushed zone to the expired
state. I couldn't really delete the element at that time, because the
iterator would become invalid.
I figured it was something like that. Perhaps the man page could
mention this? The entry for flush_zone says "Remove all information at
or below the name from the cache" but maybe instead something like "Set
the TTL to 0 for all cache entries at and below the name."
Yes, I'll fix that! It doesn't set the TTL to 0, but I'll phrase it
like, it sets the item to TTL expired.
I could however, set other flags or things to the expired data. Eg
SERVFAIL. But then the customer receives servfail and the prefetch
happens, instead of the customer receiving the old data and a prefetch
happens, which is what there is now.
I prefer that serve-expired still actually serves expired entries if
they're in the cache. I was confused because I thought I had flushed
the cache, that's all.
However, there seems to be a related-but-different bug: I'm not seeing
any prefetching. After the flush, no upstream query appears until after
the flushed entry's original TTL elapses.
Yes that is a bug! Fixed it (patch included below). Thanks for the report!
The bug was that it did not set the prefetch_ttl to expired.
Best regards, Wouter
Index: daemon/remote.c
===
--- daemon/remote.c (revision 4608)
+++ daemon/remote.c (working copy)
@@ -1649,6 +1649,7 @@
struct reply_info* d = (struct reply_info*)e->data;
if(d->ttl > inf->expired) {
d->ttl = inf->expired;
+ d->prefetch_ttl = inf->expired;
inf->num_msgs++;
}
}
Thanks,
M.
Re: serve-expired seems to break flush_zone
Hi Marc,
On 06/04/18 17:05, Marc Branchaud wrote:
> On 2018-04-06 02:47 AM, W.C.A. Wijngaards via Unbound-users wrote:
>> Hi Marc,
>>
>> On 04/04/18 20:29, Marc Branchaud via Unbound-users wrote:
>>> Hi all,
>>>
>>> I have a simple forward-everything setup with serve-expired enabled:
>>>
>>> server:
>>> serve-expired: yes
>>> forward-zone:
>>> name: .
>>> forward-addr: X.X.X.X
>>>
>>> If I use "flush_zone ." to clear the cache, I still get cache hits for
>>> supposedly-absent entries (dump_cache shows that the cache is empty).
>>>
>>> When I turn serve-expired off, "flush_zone ." results in cache misses
>>> for flushed entries.
>>>
>>> With serve-expired on, I can only seem to force a cache miss by
>>> explicitly flushing a name (e.g. "flush google.com"). I really want to
>>> clear the entire cache, though.
>>>
>>> Is this an intended effect of serve-expired, or is it a bug?
>>
>> Right now this is the design of flush-zone, it iterates over the cache
>> contents. And it sets every element of the flushed zone to the expired
>> state. I couldn't really delete the element at that time, because the
>> iterator would become invalid.
>
> I figured it was something like that. Perhaps the man page could
> mention this? The entry for flush_zone says "Remove all information at
> or below the name from the cache" but maybe instead something like "Set
> the TTL to 0 for all cache entries at and below the name."
Yes, I'll fix that! It doesn't set the TTL to 0, but I'll phrase it
like, it sets the item to TTL expired.
>
>> I could however, set other flags or things to the expired data. Eg
>> SERVFAIL. But then the customer receives servfail and the prefetch
>> happens, instead of the customer receiving the old data and a prefetch
>> happens, which is what there is now.
>
> I prefer that serve-expired still actually serves expired entries if
> they're in the cache. I was confused because I thought I had flushed
> the cache, that's all.
>
> However, there seems to be a related-but-different bug: I'm not seeing
> any prefetching. After the flush, no upstream query appears until after
> the flushed entry's original TTL elapses.
Yes that is a bug! Fixed it (patch included below). Thanks for the report!
The bug was that it did not set the prefetch_ttl to expired.
Best regards, Wouter
Index: daemon/remote.c
===
--- daemon/remote.c (revision 4608)
+++ daemon/remote.c (working copy)
@@ -1649,6 +1649,7 @@
struct reply_info* d = (struct reply_info*)e->data;
if(d->ttl > inf->expired) {
d->ttl = inf->expired;
+ d->prefetch_ttl = inf->expired;
inf->num_msgs++;
}
}
>
> Thanks,
>
> M.
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Re: serve-expired seems to break flush_zone
On 2018-04-06 02:47 AM, W.C.A. Wijngaards via Unbound-users wrote: Hi Marc, On 04/04/18 20:29, Marc Branchaud via Unbound-users wrote: Hi all, I have a simple forward-everything setup with serve-expired enabled: server: serve-expired: yes forward-zone: name: . forward-addr: X.X.X.X If I use "flush_zone ." to clear the cache, I still get cache hits for supposedly-absent entries (dump_cache shows that the cache is empty). When I turn serve-expired off, "flush_zone ." results in cache misses for flushed entries. With serve-expired on, I can only seem to force a cache miss by explicitly flushing a name (e.g. "flush google.com"). I really want to clear the entire cache, though. Is this an intended effect of serve-expired, or is it a bug? Right now this is the design of flush-zone, it iterates over the cache contents. And it sets every element of the flushed zone to the expired state. I couldn't really delete the element at that time, because the iterator would become invalid. I figured it was something like that. Perhaps the man page could mention this? The entry for flush_zone says "Remove all information at or below the name from the cache" but maybe instead something like "Set the TTL to 0 for all cache entries at and below the name." I could however, set other flags or things to the expired data. Eg SERVFAIL. But then the customer receives servfail and the prefetch happens, instead of the customer receiving the old data and a prefetch happens, which is what there is now. I prefer that serve-expired still actually serves expired entries if they're in the cache. I was confused because I thought I had flushed the cache, that's all. However, there seems to be a related-but-different bug: I'm not seeing any prefetching. After the flush, no upstream query appears until after the flushed entry's original TTL elapses. Thanks, M.
Re: serve-expired seems to break flush_zone
Hi Marc, On 04/04/18 20:29, Marc Branchaud via Unbound-users wrote: > Hi all, > > I have a simple forward-everything setup with serve-expired enabled: > > server: > serve-expired: yes > forward-zone: > name: . > forward-addr: X.X.X.X > > If I use "flush_zone ." to clear the cache, I still get cache hits for > supposedly-absent entries (dump_cache shows that the cache is empty). > > When I turn serve-expired off, "flush_zone ." results in cache misses > for flushed entries. > > With serve-expired on, I can only seem to force a cache miss by > explicitly flushing a name (e.g. "flush google.com"). I really want to > clear the entire cache, though. > > Is this an intended effect of serve-expired, or is it a bug? Right now this is the design of flush-zone, it iterates over the cache contents. And it sets every element of the flushed zone to the expired state. I couldn't really delete the element at that time, because the iterator would become invalid. I could however, set other flags or things to the expired data. Eg SERVFAIL. But then the customer receives servfail and the prefetch happens, instead of the customer receiving the old data and a prefetch happens, which is what there is now. Best regards, Wouter > > Thanks! > > M. signature.asc Description: OpenPGP digital signature
serve-expired seems to break flush_zone
Hi all, I have a simple forward-everything setup with serve-expired enabled: server: serve-expired: yes forward-zone: name: . forward-addr: X.X.X.X If I use "flush_zone ." to clear the cache, I still get cache hits for supposedly-absent entries (dump_cache shows that the cache is empty). When I turn serve-expired off, "flush_zone ." results in cache misses for flushed entries. With serve-expired on, I can only seem to force a cache miss by explicitly flushing a name (e.g. "flush google.com"). I really want to clear the entire cache, though. Is this an intended effect of serve-expired, or is it a bug? Thanks! M.
