On 07/07/2010 17:36, André Warnier wrote: > Pid wrote: >> On 07/07/2010 15:08, mmg wrote: >>> Hello, >>> >>> I've recently deployed an application on our Linux staging server; a >>> Tomcat >>> 5.5.28 server on Java 1.5.0_09-b01. At some point, the application >>> makes a >>> call to request.getLocalName(). For some reason, this call takes a >>> very long >>> time (about 20 seconds!). I profiled the application, and I see that >>> tomcat >>> calls InetAddress.getHostName() in turn. This performs a reverse DNS >>> lookup. >>> It's this reverse DNS lookup that takes so long (since our host >>> doesn't have >>> a DNS address the resolve fails). >>> >>> Is there a way to disable this reverse DNS lookup in Tomcat or is there >>> anything else I can do to speed this up? >> >> It's nothing to do with Tomcat. >> >> There are JVM settings which apply to networking & DNS lookups. You >> might be affected by these, depending on your system configuration. >> >> http://java.sun.com/j2se/1.5.0/docs/guide/net/properties.html >> >> > That is an interesting page per se, but I don't see anything there that > seems related to the inverse DNS lookup which the application seems to > be triggering.
Maybe it's trying a dud ip6 connection first. p > To complete my earlier suggestion of adding a corresponding line to > /etc/hosts, like > > 1.2.3.4 somename.localdomain > > (replacing the first part by the real IP address of the host) > > which will work if the system's resolver is configured (in > /etc/nsswitch.conf) to look at that file first. > But if it does not, there are more things you can do at the system level : > > 1) change nsswitch.conf to indeed do "files" first > OR > 2) make the above change to /etc/hosts AND > run a local dnsmasq daemon (with the configuration options to have it > read /etc/hosts) and set /etc/resolv.conf to have this line first > nameserver 127.0.0.1 > > This last is a gain anyway in terms of efficiency, because dnsmasq will > cache the resolved entries and avoid further lookups into /etc/hosts > (and other DNS lookups, such as if the application is also doing client > address lookups e.g.). > > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org >
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