Re: Re: Is gethostbyaddr() slow?

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kalinga wrote:

if you are quering a external host, the bad network conditions may

cause delay in results.

if your server is connected to a heavily loaded hub/ cheap switch, or
the target hosts DNS servers are poorly configured/ slow in responce
it adds further delay to your result.

try dig/ nslookup on your server for the target hostname/address, you
may experience the same delay as with the php function.


Thanks for the reply. The problem I had - and that I was trying to briefly describe - is not quite explained by slow DNS lookup, at least not so far. I have one script, run on the same machine:

takes less than 1 second on CLI:

# php gethostbyname.php
Content-type: text/html
X-Powered-By: PHP/4.3.2

gethostbyname(www.imakenews.com) took 0.0010 s and resolved to 208.254.39.65<br> gethostbyname(rssnewsapps.ziffdavis.com) took 0.0005 s and resolved to 63.87.252.162<br> gethostbyname(itpapers.zdnet.com) took 0.1922 s and resolved to 216.239.113.159<br> gethostbyname(rssnewsapps.ziffdavis.com) took 0.0005 s and resolved to 63.87.252.162<br>


Running CLI again, host names are apparently cached, because then they all return in .0005 seconds.

takes 20 seconds under Apache 2.0.46:

gethostbyname(www.imakenews.com) took 5.0071 s and resolved to 208.254.39.65 gethostbyname(rssnewsapps.ziffdavis.com) took 5.0099 s and resolved to 63.87.252.162 gethostbyname(itpapers.zdnet.com) took 5.0097 s and resolved to 216.239.113.159 gethostbyname(rssnewsapps.ziffdavis.com) took 5.0099 s and resolved to 63.87.252.162


This will happen consistently, with less than 1/100 s variation in time for each lookup.


Any DNS lookup tools are perfectly fast when run from the command line. Also, other machines in the same subnet, using the same DNS servers, using 99% same apache config files (I diff'ed 'em) run just as fast under same apache/php version as they do command line. It's hard to imagine what external DNS problem could exist that would affect only one of our servers, and on that one, only apache/php and nothing command line. Something else is going on, but my initial tries of downgrading/upgrading both php and apache haven't made a different yet. Perhaps you have another suggestion?


Thanks,

kgt

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