On Tue, Jan 18, 2005 at 09:52:41PM +0000, eric wyzerski wrote: > >From: Claudio Jeker <[EMAIL PROTECTED]> > >To: [email protected] > >Subject: Re: Bad Performance - Help plz > >Date: Tue, 18 Jan 2005 21:57:59 +0059 > > > >On Tue, Jan 18, 2005 at 07:51:14PM +0000, eric wyzerski wrote: > >> Hi, > >> > >> Here some output from tcpdump (qmail-ldap is on 10.1.1.242) > >> > >> 14:47:35.603770 IP 10.1.1.232.54339 > 10.1.1.7.ldap: S > >31007374:31007374(0) > >> win 65535 <mss 1460,nop,nop,sackOK,nop,wscale 1,nop,nop,timestamp > >1213462 0> > >> 14:47:35.604238 IP 10.1.1.7.ldap > 10.1.1.232.54339: S > >> 3130696555:3130696555(0) ack 31007375 win 65535 <mss 1460,nop,wscale > >> 0,nop,nop,timestamp 0 0,nop,nop,sackOK> > >> 14:47:35.604280 IP 10.1.1.232.54339 > 10.1.1.7.ldap: . ack 1 win 33304 > >> <nop,nop,timestamp 1213462 0> > >> 14:47:35.604348 IP 10.1.1.232.54339 > 10.1.1.7.ldap: P 1:73(72) ack 1 > >win > >> 33304 <nop,nop,timestamp 1213462 0> > >> 14:47:35.606936 IP 10.1.1.7.ldap > 10.1.1.232.54339: P 1:23(22) ack 73 > >win > >> 65463 <nop,nop,timestamp 4594074 1213462> > >> 14:47:35.607102 IP 10.1.1.232.54339 > 10.1.1.7.ldap: P 73:275(202) ack > >23 > >> win 33304 <nop,nop,timestamp 1213462 4594074> > >> 14:47:35.608795 IP 10.1.1.7.ldap > 10.1.1.232.54339: P 23:458(435) ack > >275 > >> win 65261 <nop,nop,timestamp 4594074 1213462> > >> 14:47:35.707827 IP 10.1.1.232.54339 > 10.1.1.7.ldap: . ack 458 win 33201 > >> <nop,nop,timestamp 1213473 4594074> > >> > >> <Look five second here before sending the data> > >> > >> 14:47:40.955095 IP 10.1.1.232.54339 > 10.1.1.7.ldap: P 275:282(7) ack > >458 > >> win 33304 <nop,nop,timestamp 1213997 4594074> > >> 14:47:40.955130 IP 10.1.1.232.54339 > 10.1.1.7.ldap: F 282:282(0) ack > >458 > >> win 33304 <nop,nop,timestamp 1213997 4594074> > >> 14:47:40.955287 IP 10.1.1.232.53539 > 10.1.1.7.ldap: S > >> 2128629471:2128629471(0) win 65535 <mss 1460,nop,nop,sackOK,nop,wscale > >> 1,nop,nop,timestamp 1213997 0> > >> 14:47:40.955592 IP 10.1.1.7.ldap > 10.1.1.232.54339: F 458:458(0) ack > >282 > >> win 65254 <nop,nop,timestamp 4594128 1213997> > >> 14:47:40.955626 IP 10.1.1.232.54339 > 10.1.1.7.ldap: F 282:282(0) ack > >459 > >> win 33303 <nop,nop,timestamp 1213997 4594128> > >> 14:47:40.955663 IP 10.1.1.7.ldap > 10.1.1.232.54339: . ack 283 win 65254 > >> <nop,nop,timestamp 4594128 1213997> > >> 14:47:40.955807 IP 10.1.1.7.ldap > 10.1.1.232.53539: S > >> 1456763827:1456763827(0) ack 2128629472 win 65535 <mss 1460,nop,wscale > >> 0,nop,nop,timestamp 0 0,nop,nop,sackOK> > >> 14:47:40.955830 IP 10.1.1.232.53539 > 10.1.1.7.ldap: . ack 1 win 33304 > >> <nop,nop,timestamp 1213997 0> > >> 14:47:40.955873 IP 10.1.1.232.53539 > 10.1.1.7.ldap: P 1:93(92) ack 1 > >win > >> 33304 <nop,nop,timestamp 1213997 0> > >> 14:47:40.958823 IP 10.1.1.7.ldap > 10.1.1.232.53539: P 1:23(22) ack 93 > >win > >> 65443 <nop,nop,timestamp 4594128 1213997> > >> 14:47:40.958903 IP 10.1.1.232.53539 > 10.1.1.7.ldap: P 93:100(7) ack 23 > >win > >> 33304 <nop,nop,timestamp 1213998 4594128> > >> 14:47:40.958920 IP 10.1.1.232.53539 > 10.1.1.7.ldap: F 100:100(0) ack 23 > >> win 33304 <nop,nop,timestamp 1213998 4594128> > >> 14:47:40.959616 IP 10.1.1.7.ldap > 10.1.1.232.53539: . ack 101 win 65436 > >> <nop,nop,timestamp 4594128 1213998> > >> 14:47:40.959626 IP 10.1.1.7.ldap > 10.1.1.232.53539: F 23:23(0) ack 101 > >win > >> 65436 <nop,nop,timestamp 4594128 1213998> > >> 14:47:40.959693 IP 10.1.1.232.53539 > 10.1.1.7.ldap: . ack 24 win 33303 > >> <nop,nop,timestamp 1213998 4594128> > >> > >> as you can see we have a hole of five seconds without reason and its > >> happens very often, so the performance of the mail server is really bad. > >> So, any idea to solve this problem? > >> Thank you > >> > > > >Is your database correctly indexed? > > Yes it is. > > I think the problem is qmail-ldap is waiting sometimes before sending his > query to the LDAP directory, and I dont know why. Moreover, I send a > previous post on the mailing list to know how I can tell qmail-ldap to keep > a persistent connection to the LDAP database, maybe it will solve the > problem but I got no answer and I dont see anything about persistent > connection in the doc. > Any other idea?
>>> <Look five second here before sending the data> >>> >>> 14:47:40.955095 IP 10.1.1.232.54339 > 10.1.1.7.ldap: P 275:282(7) ack 458 >>> win 33304 <nop,nop,timestamp 1213997 4594074> >>> 14:47:40.955130 IP 10.1.1.232.54339 > 10.1.1.7.ldap: F 282:282(0) ack 458 >>> win 33304 <nop,nop,timestamp 1213997 4594074> >>> 14:47:40.955592 IP 10.1.1.7.ldap > 10.1.1.232.54339: F 458:458(0) ack 282 >>> win 65254 <nop,nop,timestamp 4594128 1213997> This is looking like a delayed close. qmail-ldap sends a close message and the closes the channel and the server is closing the channel directly afterwards. qmail-ldap will use one session to do all needed lookups. Especially qmail-verify will try to keep the session open but closes it after a short time of inactivity. Using persistent connections in qmail-ldap is not feasible because of the design of qmail. A large rewrite would be needed to do it with persistent connections. -- :wq Claudio
