Hi Julius,
Thanks for the patient and information, that helped a lot.
I just learned from other threads myself as well.
I'm using JDK5.
But here comes another question, is the any limit in the default DNS
caching?
I mean, for example, if we use the httpclient on a web spider project,
there must have millions of hostnames
will java default DNS cache all the ip-hostname mapping?
Anyway, seems it'd done in jre side, there's nothing to do with
httpclient side.
Another question is that is there any socket connection limitation in
httpclient?
I saw there is setDefaultMaxConnectionsPerHost default to 2
setMaxTotalConnections default to 20
Is that mean if i setDefaultMaxConnectionsPerHost to 10, the
setMaxTotalConnections will set to 100? or still 20?
And is there any MAX value for these two methods?
Last question is, where can i learn more about httpclient? any books
about it, and any performance results about it? any equivalent projects
in java?
Thanks a million
James.
Hi, James,
Sun Java 5 and previous cache all DNS lookups forever, anyway.
(Drives me crazy since it really screws up DNS-based load-balancing!).
So once that DNS lookup is done the one time - that's it ! - never
done again!
From reading "jre/lib/security/java.security", looks like Sun Java 6
caches all DNS lookups for 30 seconds when a security manager isn't
set.
These caching settings can be modified by editing:
jre/lib/security/java.security
Here's a snippet from the Sun Java 5 version:
#
# The Java-level namelookup cache policy for successful lookups:
#
# any negative value: caching forever
# any positive value: the number of seconds to cache an address for
# zero: do not cache
#
# default value is forever (FOREVER). For security reasons, this
# caching is made forever when a security manager is set.
#
# NOTE: setting this to anything other than the default value can have
# serious security implications. Do not set it unless
# you are sure you are not exposed to DNS spoofing attack.
#
#networkaddress.cache.ttl=-1
yours,
Julius
On 3/8/07, maomaode <[EMAIL PROTECTED]> wrote:
Hi,
I think it can improve the performance, when we do host lookup it
require extra cost, if we can cache the hostname-ip map, then if there
is same hostname, we can use ip directly, no dns resolve will be
required.
I guess it improve the performance.
> Why?
>
>
> "Jakarta Commons Users List" <[email protected]> wrote:
>
>
>> Hi,
>>
>> I just noticed that in
>> org/apache/commons/httpclient/protocol/DefaultProtocolSocketFactory
>>
>> we use the Socket(host, port), why not use Socket(InetAddress, port)
>>
>> I guess the the Socket(host, port) will eventually call
>> Socket(InetAddress, port), right?
>> I think if we use Socket(InetAddress, port), can improve the
productivity.
>>
>> thoughts?
>>
>> James.
>>
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>
>
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