Re: Is gethostbyaddr() slow?

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On 8/4/05, Kristen G. Thorson <kthorson@xxxxxxxxxxxxxxxxxxxxxx> wrote:
> 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?

could you please mention the environment, i mean, the os, and the
versions of php? is it binary install or a compile?

> 
> 
> Thanks,
> 
> kgt
> 
> 
> 
> 
>

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