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From "Nathan Beyer" <ndbe...@apache.org>
Subject Re: [classlib][luni] put only host name in UnknownHostException
Date Thu, 24 Apr 2008 14:08:34 GMT
On Thu, Apr 24, 2008 at 3:59 AM, Tim Ellison <t.p.ellison@gmail.com> wrote:

> Nathan Beyer wrote:
>
>> https://issues.apache.org/jira/browse/HARMONY-5784
>>
>> Anyone have any issue with making this change? Currently, the behavior is
>> such that the host is in the message, but with the additional "No such
>> file
>> or directory" message. There doesn't seem to be much value in the
>> additional
>> message, so changing this to just be the host that was passed in is pretty
>> trivial.
>>
>
> Yeah, can dump the bogus information from the message.
>
>  However, when unwinding this a bit, there's this NegativeCache class that
>> stores failed lookups and the message failure. Is this really needed? Is
>> it
>> appropriate? There's already a cache of resolved InetAddress object that
>> were found, but this cache has a expiry, as I would have expected, but the
>> NegativeCache doesn't. Any thoughts or comments on eliminating this
>> negative
>> cache bit? It seems like the negative cache isn't being maintained
>> properly
>> (no expiry, etc), so if a host became accessible over time, it wouldn't be
>> accessible. Additionally, I don't think the overhead of the memory, though
>> minimal, is really worth not executing a lookup, which would already be
>> offset by resolvable hosts in the other cache.
>>
>
> The negative cache is needed, and it is described by the spec for
> InetAddress [1] (see "InetAddress Caching").
>
> It should have an expiry mechanism which admins can tweak using the
> networkaddress.cache.negative.ttl property.


Ahh, yes, indeed. The code's a bit weird, but I see it now. I'll rework it a
bit by removing the storage of the failed message.

-Nathan

>
>
> [1] http://java.sun.com/j2se/1.5.0/docs/api/java/net/InetAddress.html
>
> Regards,
> Tim
>

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