Subject: non-deliveries from scheduler and BIND lookups

From: Eugene Crosser <[email-masked]>
Date: 27 Nov 2002 16:16:34 +0300

Matti,

it seems to be a problem that shows up on high load.  When the scheduler
generates non-delivery report, it makes DNS lookup for local host name
(mind you, *despite* the host name in both short and FQDN form is in
/etc/hosts, it still does DNS resolve).  When the traffic is high and
the DNS resolver is slow, this results in slowdown of the whole queue
processing.  First, it seems that using DNS resolution from the
scheduler should be limited to a bare minimum, because onlike other
parts of Zmailer, this is a single process.  Second, repeated resolving
of own host name does not make sense in any case...  Any ideas?

open("/var/spool/postoffice/public/gnome02.net.rol.ru:14269",
O_RDWR|O_CREAT|O_E
XCL, 0600) = 358
shmat(358, 0x833df2d, 0x1ptrace: umoven: Input/output error
)              = ?
shmat(358, 0x833df2d, 0x2ptrace: umoven: Input/output error
)              = ?
fstat64(0x166, 0xbfff7b7c)              = 0
lseek(358, 0, SEEK_CUR)                 = 0
fstat64(0x166, 0xbfff7c6c)              = 0
uname({sys="Linux", node="gnome02", ...}) = 0
socket(PF_UNIX, SOCK_STREAM, 0)         = 359
connect(359, {sin_family=AF_UNIX,
path="                                        
                                               /var/run/.nscd_socket"},
110) = -
1 ENOENT (No such file or directory)
close(359)                              = 0
open("/etc/hosts", O_RDONLY)            = 359
shmat(359, 0x1, 0x1ptrace: umoven: Input/output error
)                    = ?
shmat(359, 0x1, 0x2ptrace: umoven: Input/output error
)                    = ?
fstat64(0x167, 0xbfff726c)              = 0
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
-1, 0) = 0
x40016000
read(359, "#\n# Internet host table\n#\n# $Id:"..., 4096) = 2232
read(359, "", 4096)                     = 0
close(359)                              = 0
munmap(0x40016000, 4096)                = 0
socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 359
connect(359, {sin_family=AF_INET, sin_port=htons(53),
sin_addr=inet_addr("194.67
.2.114")}}, 28) = 0
send(359, "9\365\1\0\0\1\0\0\0\0\0\0\7gnome02\3net\3rol\2ru\0"..., 36,
0) = 36
gettimeofday({1038400810, 934062}, NULL) = 0
poll([{fd=359, events=POLLIN, revents=POLLIN}], 1, 5000) = 1
recvfrom(359,
"9\365\201\200\0\1\0\0\0\1\0\0\7gnome02\3net\3rol\2ru\0"..., 1024,
 0, {sin_family=AF_INET, sin_port=htons(53),
sin_addr=inet_addr("194.67.2.114")}
}, [16]) = 94
close(359)                              = 0
socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 359
connect(359, {sin_family=AF_INET, sin_port=htons(53),
sin_addr=inet_addr("194.67
.2.114")}}, 28) = 0
send(359, "9\366\1\0\0\1\0\0\0\0\0\0\7gnome02\0\0\34\0\1", 25, 0) = 25
gettimeofday({1038400810, 971927}, NULL) = 0
poll([{fd=359, events=POLLIN, revents=POLLIN}], 1, 5000) = 1
recvfrom(359,
"9\366\201\203\0\1\0\0\0\1\0\0\7gnome02\0\0\34\0\1\0\0\6"..., 1024
, 0, {sin_family=AF_INET, sin_port=htons(53),
sin_addr=inet_addr("194.67.2.114")
}}, [16]) = 100
close(359)                              = 0

-- 
Eugene Crosser, head of Internet Applications section, +7 501 787 1000
ROL, Teleross, Golden Telecom, http://user.rol.ru/~crosser/

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