net: DNS resolves slowly #21906
Comments
|
Thank you for raising this issue. Please provide some sample code that reproduces the problem.
… On 16 Sep 2017, at 20:19, mupeng ***@***.***> wrote:
What version of Go are you using (go version)?
go1.8.1 & go1.9
Does this issue reproduce with the latest release?
not found yet
What operating system and processor architecture are you using (go env)?
GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/XXX/go"
GORACE=""
GOROOT="/home/XXX/local/go1.9/go"
GOTOOLDIR="/home/XXX/local/go1.9/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build967902580=/tmp/go-build"
CXX="g++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
What did you do?
when I used httpclient to send post request to a URL, I found it took more time than use python or java in the same environment. go took 6S, python took less than 1S.
After analysis and exclusion, I found it spend too much time on DNS resolve. if I replace domain names with the IP, the request take almost as much time as python&java take.
One more thing, all above is only for a specified domain, I'm not sure if there's other special domain name like this cause this problem.
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// For security's sake, sorry, I can't provide detailed domain names
url := ""
// json content
payload := strings.NewReader("")
req, _ := http.NewRequest("POST", url, payload)
req.Header.Add("content-type", "application/json")
req.Header.Add("cache-control", "no-cache")
client := &http.Client{
Timeout: time.Duration(3000) * time.Millisecond,
}
now := time.Now()
res, err := client.Do(req)
cost := time.Since(now)
if err != nil {
fmt.Println(err)
return
}
defer res.Body.Close()
body, _ := ioutil.ReadAll(res.Body)
fmt.Println(string(body))
fmt.Println(cost.Seconds() * 1e3)
now = time.Now()
ns, err := net.LookupHost("DOMAIN")
cost = time.Since(now)
fmt.Println(cost.Seconds() * 1e3)
if err != nil {
fmt.Printf("Err: %s", err.Error())
return
}
for _, n := range ns {
fmt.Printf("%s\n", n)
} |
dsnet
added
the
NeedsInvestigation
|
@mupengX the code you pasted isn't self-contained. Please give an entire program - as small as possible - that reproduces the issue. You can use https://play.golang.org/. |
mvdan
added
the
WaitingForInfo
|
i'm sorry for that. The go playground does not allow HTTP requests for security. package main
import (
"fmt"
"io/ioutil"
"net"
"net/http"
"strings"
"time"
)
func main() {
// For security's sake, sorry, I can't provide detailed domain names
url := ""
// json content
payload := strings.NewReader("")
req, _ := http.NewRequest("POST", url, payload)
req.Header.Add("content-type", "application/json")
req.Header.Add("cache-control", "no-cache")
client := &http.Client{
Timeout: time.Duration(3000) * time.Millisecond,
}
now := time.Now()
res, err := client.Do(req)
cost := time.Since(now)
if err != nil {
fmt.Println(err)
return
}
defer res.Body.Close()
body, _ := ioutil.ReadAll(res.Body)
fmt.Println(string(body))
fmt.Println(cost.Seconds() * 1e3)
} |
|
Thank you for sharing your code sample. I'm guessing the part you are
timing is
```
now := time.Now()res, err := client.Do(req)cost := time.Since(now)
```
How have you determined that the value of cost is dominated by DNS lookup?
…On Mon, Sep 18, 2017 at 12:53 PM, mupeng ***@***.***> wrote:
i'm sorry for that. The go playground does not allow HTTP requests for
security.
This is the complete code：
package main
import (
"fmt"
"io/ioutil"
"net"
"net/http"
"strings"
"time"
)
func main() {
// For security's sake, sorry, I can't provide detailed domain names
url := ""
// json content
payload := strings.NewReader("")
req, _ := http.NewRequest("POST", url, payload)
req.Header.Add("content-type", "application/json")
req.Header.Add("cache-control", "no-cache")
client := &http.Client{
Timeout: time.Duration(3000) * time.Millisecond,
}
now := time.Now()
res, err := client.Do(req)
cost := time.Since(now)
if err != nil {
fmt.Println(err)
return
}
defer res.Body.Close()
body, _ := ioutil.ReadAll(res.Body)
fmt.Println(string(body))
fmt.Println(cost.Seconds() * 1e3)
}
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Also wondering how you came to the conclusion that it's Go's fault that the DNS resolves slowly (if it indeed is the DNS lookup that takes a while). Have you tried other tools, like |
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Have you tried using net/http/httptrace package to trace the request and confirm that the DNS lookup is your problem? There is also httpstat tool which basically collects all the timings in a request using the net/http/httptrace package and formats them in a pretty way. You can also set GODEBUG=netdns=2 to see how the DNS request is made (using Go or CGO) and force Go/CGO by using GODEBUG=netdns=go or GODEBUG=netdns=cgo. See this CL for more information on the GODEBUG=netdns configuration. |
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First thanks for your suggestion @nussjustin Maybe it is a special case with this domain name. Thanks! |
|
@nussjustin package main
import (
"fmt"
"io/ioutil"
"net"
"net/http"
"net/http/httptrace"
"strings"
"time"
)
func main() {
dialer := &net.Dialer{Timeout: 7 * time.Second}
// For security's sake, sorry, I can't provide detailed domain names
url := ""
// json content
payload := strings.NewReader("")
req, _ := http.NewRequest("POST", url, payload)
req.Header.Add("content-type", "application/json")
req.Header.Add("cache-control", "no-cache")
trace := &httptrace.ClientTrace{
DNSStart: func(dnsInfo httptrace.DNSStartInfo) {
fmt.Printf("dns start: %v\n", time.Now())
},
DNSDone: func(dnsDoneInfo httptrace.DNSDoneInfo) {
fmt.Printf("dns end: %v\n", time.Now())
},
}
req = req.WithContext(httptrace.WithClientTrace(req.Context(), trace))
transport := &http.Transport{
DialContext: (dialer).DialContext,
Dial: (dialer).Dial,
TLSHandshakeTimeout: 2 * time.Second,
}
client := &http.Client{
Transport: transport,
Timeout: time.Duration(10000) * time.Millisecond,
}
now := time.Now()
res, err := client.Do(req)
cost := time.Since(now)
if err != nil {
fmt.Println(err)
return
}
defer res.Body.Close()
body, _ := ioutil.ReadAll(res.Body)
fmt.Println(string(body))
fmt.Printf("client cost: %v\n", cost.Seconds()*1e3)
}and get the result : dns start: 2017-09-26 15:45:28.148847712 +0800 CST
dns end: 2017-09-26 15:45:33.15817369 +0800 CST
client cost: 5114.887975000001 |
ianlancetaylor
removed
the
WaitingForInfo
|
CC @iangudger |
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@mupengX, would it be possible for you to try again with tip? The native Go resolver has been mostly rewritten since Go 1.10. |
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@iangudger - Possibly it is still there in 1.10. See #26960 |
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5114ms is fairly suspicious. IIRC, the Go DNS resolvers includes 5s timer for refreshing |
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@mupengX, sorry if I wasn't clear, I meant please re-test with 1.11. |
agnivade
added
the
WaitingForInfo
|
Experiencing very slow DNS lookups only for internal (intranet) addresses on Linux (RHEL 7.5) with Go 1.11. This is not an issue with Go 1.10. Here are some of the relevant details: Go 1.11go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/var/lib/jenkins/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/var/lib/jenkins/go"
GOPROXY=""
GORACE=""
GOROOT="/var/lib/jenkins/tools/org.jenkinsci.plugins.golang.GolangInstallation/Go_1.11"
GOTMPDIR=""
GOTOOLDIR="/var/lib/jenkins/tools/org.jenkinsci.plugins.golang.GolangInstallation/Go_1.11/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build608307955=/tmp/go-build -gno-record-gcc-switches"
GODEBUG=netdns=2 httpstat https://jira.faa.gov
go package net: dynamic selection of DNS resolver
go package net: hostLookupOrder(jira.faa.gov) = files,dns
namelookup:10049ms
Go 1.10go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/var/lib/jenkins/.cache/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/var/lib/jenkins/go_1.10"
GORACE=""
GOROOT="/var/lib/jenkins/tools/org.jenkinsci.plugins.golang.GolangInstallation/Go"
GOTMPDIR=""
GOTOOLDIR="/var/lib/jenkins/tools/org.jenkinsci.plugins.golang.GolangInstallation/Go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build266949896=/tmp/go-build -gno-record-gcc-switches"
GODEBUG=netdns=2 httpstat https://jira.faa.gov
go package net: dynamic selection of DNS resolver
go package net: hostLookupOrder(jira.faa.gov) = files,dns
namelookup:35ms
Non-Go toolshost -v jira.faa.gov
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 64067
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;jira.faa.gov. IN A
;; ANSWER SECTION:
jira.faa.gov. 7200 IN A 172.x.x.x
Received 46 bytes from 172.x.x.x#53 in 7 ms
Trying "jira.faa.gov"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57404
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
;jira.faa.gov. IN AAAA
;; AUTHORITY SECTION:
faa.gov. 0 IN SOA <omitted>. <omitted>. 2018082800 10800 1800 604800 1800
Received 81 bytes from 172.x.x.x#53 in 2 ms
Trying "jira.faa.gov"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13241
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
;jira.faa.gov. IN MX
;; AUTHORITY SECTION:
faa.gov. 0 IN SOA <omitted>. <omitted>. 2018082800 10800 1800 604800 1800
Received 81 bytes from 172.x.x.x#53 in 1 msdig jira.faa.gov
; <<>> DiG 9.9.4-RedHat-9.9.4-61.el7 <<>> jira.faa.gov
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12472
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4000
;; QUESTION SECTION:
;jira.faa.gov. IN A
;; ANSWER SECTION:
jira.faa.gov. 7200 IN A 172.x.x.x
;; Query time: 3 msec
;; SERVER: 172.x.x.x#53(172.x.x.x)
;; WHEN: Tue Aug 28 22:00:59 CDT 2018
;; MSG SIZE rcvd: 57while true; do dig jira.faa.gov | grep time; sleep 2; done
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 10 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 2 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msec
;; Query time: 1 msecNotes
|
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Is there an entry for jira.faa.gov in your hosts file? Would it be possible for you to collect packet captures with tcpdump and post them here? |
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There is no entry for |
|
Posting strace -f -e trace=network -s 10000 -r httpstat https://jira.faa.gov
strace: Process 25366 attached
strace: Process 25365 attached
strace: Process 25367 attached
[pid 25364] 0.000000 socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 3
[pid 25366] 0.001671 socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 5
[pid 25366] 0.000275 setsockopt(5, SOL_SOCKET, SO_BROADCAST, [1], 4) = 0
[pid 25366] 0.000494 connect(5, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP A>")}, 16) = 0
[pid 25366] 0.000556 getsockname(5, {sa_family=AF_INET, sin_port=htons(49727), sin_addr=inet_addr("<Private IP B>")}, [16]) = 0
[pid 25366] 0.000180 getpeername(5, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP A>")}, [16]) = 0
[pid 25366] 0.000714 setsockopt(3, SOL_SOCKET, SO_BROADCAST, [1], 4) = 0
[pid 25366] 0.000415 connect(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP A>")}, 16) = 0
[pid 25366] 0.000500 getsockname(3, {sa_family=AF_INET, sin_port=htons(59083), sin_addr=inet_addr("<Private IP B>")}, [16]) = 0
[pid 25366] 0.000274 getpeername(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP A>")}, [16]) = 0
[pid 25366] 0.001471 socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 3
[pid 25366] 0.000515 setsockopt(3, SOL_SOCKET, SO_BROADCAST, [1], 4) = 0
[pid 25366] 0.000572 connect(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP C>")}, 16) = 0
[pid 25366] 0.000468 getsockname(3, {sa_family=AF_INET, sin_port=htons(60955), sin_addr=inet_addr("<Private IP B>")}, [16]) = 0
[pid 25366] 0.000324 getpeername(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP C>")}, [16]) = 0
strace: Process 25368 attached
[pid 25368] 0.002348 socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 3
[pid 25368] 0.000450 setsockopt(3, SOL_SOCKET, SO_BROADCAST, [1], 4) = 0
[pid 25368] 0.000391 connect(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP D>")}, 16) = 0
[pid 25368] 0.000463 getsockname(3, {sa_family=AF_INET, sin_port=htons(33115), sin_addr=inet_addr("<Private IP B>")}, [16]) = 0
[pid 25368] 0.000422 getpeername(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP D>")}, [16]) = 0
[pid 25368] 4.999070 socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 3
[pid 25368] 0.000830 setsockopt(3, SOL_SOCKET, SO_BROADCAST, [1], 4) = 0
[pid 25368] 0.000366 connect(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP A>")}, 16) = 0
[pid 25368] 0.000610 getsockname(3, {sa_family=AF_INET, sin_port=htons(45386), sin_addr=inet_addr("<Private IP B>")}, [16]) = 0
[pid 25368] 0.000294 getpeername(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP A>")}, [16]) = 0
[pid 25364] 0.001998 socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 3
[pid 25364] 0.000770 setsockopt(3, SOL_SOCKET, SO_BROADCAST, [1], 4) = 0
[pid 25364] 0.000657 connect(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP C>")}, 16) = 0
[pid 25364] 0.000819 getsockname(3, {sa_family=AF_INET, sin_port=htons(42528), sin_addr=inet_addr("<Private IP B>")}, [16]) = 0
[pid 25364] 0.000676 getpeername(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP C>")}, [16]) = 0
[pid 25368] 0.002157 socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 3
[pid 25368] 0.000680 setsockopt(3, SOL_SOCKET, SO_BROADCAST, [1], 4) = 0
[pid 25368] 0.000594 connect(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP D>")}, 16) = 0
[pid 25368] 0.000794 getsockname(3, {sa_family=AF_INET, sin_port=htons(35194), sin_addr=inet_addr("<Private IP B>")}, [16]) = 0
[pid 25368] 0.000403 getpeername(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP D>")}, [16]) = 0
[pid 25368] 4.998392 socket(AF_INET, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 3
[pid 25368] 0.002491 setsockopt(3, SOL_SOCKET, SO_BROADCAST, [1], 4) = 0
[pid 25368] 0.000810 connect(3, {sa_family=AF_INET, sin_port=htons(443), sin_addr=inet_addr("<Private IP E>")}, 16) = -1 EINPROGRESS (Operation now in progress)
[pid 25364] 0.002335 getsockopt(3, SOL_SOCKET, SO_ERROR, [0], [4]) = 0
[pid 25364] 0.000560 getpeername(3, {sa_family=AF_INET, sin_port=htons(443), sin_addr=inet_addr("<Private IP E>")}, [16]) = 0
[pid 25364] 0.000620 getsockname(3, {sa_family=AF_INET, sin_port=htons(44562), sin_addr=inet_addr("<Private IP B>")}, [16]) = 0
[pid 25364] 0.000654 setsockopt(3, SOL_TCP, TCP_NODELAY, [1], 4) = 0
Connected to <Private IP E>:443
strace: Process 25377 attached
strace: Process 25377 attached
HTTP/1.1 200
<HEADERS OMITTED>
Body discarded
DNS Lookup TCP Connection TLS Handshake Server Processing Content Transfer
[ 10061ms | 8ms | 169ms | 103ms | 222ms ]
| | | | |
namelookup:10061ms | | | |
connect:10069ms | | |
pretransfer:10239ms | |
starttransfer:10343ms |
total:10565ms
[pid 25377] 0.504838 +++ exited with 0 +++
[pid 25368] 0.000415 +++ exited with 0 +++
[pid 25367] 0.000261 +++ exited with 0 +++
[pid 25366] 0.000348 +++ exited with 0 +++
[pid 25365] 0.000301 +++ exited with 0 +++
0.000270 +++ exited with 0 +++ |
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Would it be possible for you to re-run the strace also logging sendto, recvfrom, read, write, and the full arguments (packet data)? I can probably debug with that. |
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After digging into this a bit more, I believe I've isolated my issue. The [pid 25368] 0.000422 getpeername(3, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("<Private IP D>")}, [16]) = 0
[pid 25368] 4.999070 socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_IP) = 3This happens twice in the Note: the last |
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Is this the expected behavior for Go 1.11 on Linux (trying to resolve DNS lookups using all the nameservers listed in |
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I don't think so. I think the behavior in this regard is supposed to be the same as 1.10. |
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I believe I've found a way to reproduce the issue using a public domain name. The domain amc.faa.gov
search amc.faa.gov act.faa.gov ad.faa.gov faa.gov jccbi.gov
nameserver 172.25.84.100
nameserver 172.25.116.100
nameserver 172.19.50.27The last |
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First, @mvdan's bug seems to be a regression and different from the original bug. I think maybe the issue is that you are getting an empty answers section for the IPv6 lookup and that the new DNS client in 1.11 treats this as an error and then goes on to the next DNS server. |
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You are correct, the DNS nameservers used are returning empty answers for IPv6 lookups (including for |
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Returning an empty answer section is allowed. I will try to put together a fix. |
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In my service, the net.Resolver stalling 5s+ occurred once every 150 queries. This service is built in go1.11 . The AAAA reponse alway this: |
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I have filed #27525 to track this regression. |
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Timed out in state WaitingForInfo. Closing. (I am just a bot, though. Please speak up if this is a mistake or you have the requested information.) |
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@iangudger - Does #27525 supercede this ? Or should I reopen this ? |
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#27525 only supersedes the new issue here. The original issue timed out waiting for info. I think the current state is correct. |
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@iangudger |
What version of Go are you using (
go version)?go1.8.1 & go1.9
Does this issue reproduce with the latest release?
not found yet
What operating system and processor architecture are you using (
go env)?GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/XXX/go"
GORACE=""
GOROOT="/home/XXX/local/go1.9/go"
GOTOOLDIR="/home/XXX/local/go1.9/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build967902580=/tmp/go-build"
CXX="g++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
What did you do?
when I used httpclient to send post request to a URL, I found it took more time than use python or java in the same environment. go took 6S, python took less than 1S.
After analysis and exclusion, I found it spend too much time on DNS resolve. if I replace domain names with the IP, the request take almost as much time as python&java take.
One more thing, all above is only for a specified domain, I'm not sure if there's other special domain name like this cause this problem.
The text was updated successfully, but these errors were encountered: