powershell - Test-Connection Performance Better with HostName -

-

running test-connection ip address takes considerably longer running same command server's hostname.

however; if add -quiet parameter performance same (ip fraction faster, may expect).

using measure-command anomaly not show up; presumably quirk of output not being displayed.

the below code more accurately reflects anomaly seen:

$begin=(get-date).ticks;test-connection '123.45.67.89'; $a=((get-date).ticks - $begin) $begin=(get-date).ticks;test-connection 'myhostname'; $b=((get-date).ticks - $begin) $a-$b

colleagues have reproduced same issue on machines.

question: aware of may cause this? i.e. suspect it's bug (and have reported such), implies there's clever going on powershell may work differently depending on whether output displayed or not / causing quantum-like effect; it's not running commands given in order, doing (de)optimisation under covers.

my environment

os: ms windows 7 pro sp1

$psversioninfo:

name                           value                                   ----                           -----                                                                                                                                                   psversion                      4.0                                      wsmanstackversion              3.0                                      serializationversion           1.1.0.1                                  clrversion                     4.0.30319.18444                          buildversion                   6.3.9600.16406                           pscompatibleversions           {1.0, 2.0, 3.0, 4.0}                     psremotingprotocolversion      2.2

ms connect bug

https://connect.microsoft.com/powershell/feedbackdetail/view/1578010/test-connection-performance-with-ip-and-output

i did wireshark trace while running test-connection , without quiet switch parameter, supplying ipv4 address computername parameter.

when quiet switch omitted, powershell seems send not 1, 6 netbios name queries target machine, after returns formatted output.

if assign output test-connection, returns right away, pipe format-table, hangs , sends nbstat queries again

the root cause not test-connection cmdlet itself, formatted output. 1 of properties (ipv4address) scriptproperty , has following definition:

ps c:\> $ping = test-connection -computername 10.0.0.101 -count 1 ps c:\> get-member -inputobject $ping -name ipv4address | select-object -expandproperty definition system.object ipv4address {get=$iphost = [system.net.dns]::gethostentry($this.address)                     $iphost.addresslist | ?{ $_.addressfamily -eq [system.net.sockets.addressfamily]::internetwork } | select -first 1;}

so, when output shown, [system.net.dns]::gethostentry(10.0.0.101) called calculate ipv4address - causes waiting time

if don't care moot resolution of ip address, use select-object prevent calculation , output of ipv4address:

test-connection -computername 10.0.0.101 -count 1 | select address,statuscode

Comments

Post a Comment

Popular posts from this blog

Fail to load namespace Spring Security http://www.springframework.org/security/tags -

-
i have problem namespace of spring security on xhtml page. don't understand why can't load uri, , have following issue: whitelabel error page application has no explicit mapping /error, seeing fallback. tue jul 21 16:58:12 utc 2015 there unexpected error (type=not found, status=404). please need help! possible uri has been changed? best regards you using incorrect namespace url. correct url http://www.springframework.org/schema/security the error page seeing spring source website since not recognize url. try visiting http://www.springsource.org/security/tags in browser update : spring security tags used in jsp page correct tag lib declaration is: <%@ taglib prefix="sec" uri="http://www.springframework.org/security/tags" %>
Read more

Maven Javadoc 'Cannot find default setter' and fails -

-
i'm trying generate javadocs maven project, , i'm running error every time. unable parse configuration of mojo org.apache.maven.plugins:maven-javadoc-plugin:2.10.3:javadoc parameter #: cannot find default setter in class org.apache.maven.plugin.javadoc.options.group . command i'm using mvn javadoc:javadoc root directory, pom is. i don't have groups configured @ all, or have special configuration @ all. same error whether omit plugin in pom completely, add reporting, or add build plugin. i've tried adding empty groups well, , while message changes somewhat, still appears. i ran across this question , a. don't have testng dependencies, b. i'm not using command line parameters, , c. never resolved. it selenium project, suppose there similar, can't figure out. ideas? i've included maven debug stack trace below. [error] failed execute goal org.apache.maven.plugins:maven-javadoc-plugin:2.10.3:javadoc (default-cli) on project selenium: un...
Read more

sql - MySQL query optimization using coalesce -

-
can explain me why second query faster first? (first 1 takes around 40 seconds, second 1 less 0.1) select releases.feature_code, releases.platform_id, version, release_date, general_available, uri, filesize, display_name, feature_name.full_name, if ((select exists(select 1 release_exceptions releases.feature_code = release_exceptions.feature_code , releases.platform_id = release_exceptions.platform_id , releases.version = release_exceptions.version) = 1), 1, 0) release_exceptions releases left outer join platform using(platform_id) left outer join feature_name using(feature_code) order version desc; ~~~ query 2 ------------------ ~~~ select feature_code, version, release_date, general_available, platform_id, uri, filesize, display_name, feature_name.full_name, coalesce(release_exceptions, 0) release_exceptions mus.releases left outer join ( select distinct feature_code, version, platform_id, 1 release_exceptions mus.release_exceptions ) release_exceptions using ...
Read more