From: Claudio Jeker <[EMAIL PROTECTED]> To: [email protected] Subject: Re: Bad Performance - Help plz Date: Wed, 19 Jan 2005 00:03:47 +0059
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.
Hum ok, thank you for the clarification, I'll then stop looking how to make a persistent connection :)
:wq!
Eric
-- :wq Claudio
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