RE: QShell performance

So all the trouble is because every time a shell starts, qshell runs gethostbyname() in order to load the environment variables "HOSTID" and "HOSTNAME".

And if the DNS is not configured correctly, the call to gethostbyname() becomes very slow.

And since some commands trigger a lot of new shells, the entire process crawls to a halt.

Chris Hiebert
Senior Programmer/Analyst
Disclaimer: Any views or opinions presented are solely those of the author and do not necessarily represent those of the company.


-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Diego Kesselman
Sent: Wednesday, June 21, 2017 10:03 AM
To: midrange-l@xxxxxxxxxxxx
Subject: Re: QShell performance

FYI:

*Qshell Session Takes a Long for the Prompt or Time to Start and Run
Commands*

http://www-01.ibm.com/support/docview.wss?uid=nas8N1016223

Regards

Diego E. KESSELMAN


El 21/06/17 a las 10:46, mlazarus escribió:

Scott, et al,

I tried various suggestions, then took Diego's advice to look at
CHGTCPDMN. There was a DNS address specified that is either invalid
or blocked by the firewall. After removing that address "hostname"
comes back immediately as does the string with the "ls" command
embedded: QSH CMD('cd /usr/Mark/Downloads/;for file in *.h37;do ls
"$file";done'). I haven't tested the command with the "mv", but I
assume that it will follow suit.

Thanks to all that responded, for the suggestions.

For good measure, I put the invalid address back in, just to make
sure that it wasn't a fluke. Sure enough, the old long lag times
returned! Even removing the address while the command was running
caused the list to start flying by. Any ideas why this would occur?

-mark

On 6/19/2017 1:36 AM, Scott Klement wrote:

Mark,

Something isn't right here -- 25 seconds to run a "mv" command? It
should be sub-second. Is your subsystem low on resources?

Your second example, with the "ls" might be slow if it's a very big
directory. That one is not a good way to do things... but. the
first one shouldn't be too bad. The biggest performance issue, as I
see it, is calling "basename" since that will launch a whole new job
each time you run it.

But, even with that, I don't get why it'd take 25 seconds.

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