Re^2: Redirect data and Filehandle manipulation (STDIN x Disk IO)

I really need to work without write temp file, to improve performance on postfix smtp servers.

After your response I found references for "< redirection" ("opens the file for input, default unit 0"), and confirm with lsof command:

   script < input &
# lsof -p PID 
COMMAND   PID USER   FD   TYPE DEVICE     SIZE    NODE NAME
... cut ...
perl    20316 root    0r   REG    8,2    43151 1564123 /root/av/mail.e
+xploits
perl    20316 root    1u   CHR  136,2                4 /dev/pts/2
perl    20316 root    2u   CHR  136,2                4 /dev/pts/2
[download]

Thank's for your response!

--
Marco Antonio
Rio-PM
Comment on Re^2: Redirect data and Filehandle manipulation (STDIN x Disk IO)
Download Code

Replies are listed 'Best First'.
Re^3: Redirect data and Filehandle manipulation (STDIN x Disk IO) by Tanktalus (Canon) on Jul 01, 2005 at 17:53 UTC
To be honest, I would still use a temp file. And then, because this is perl, you could change it from an IO::File to an IO::Scalar later and compare if you're really saving any clock time. I'm betting it's not going to be significant on most modern hardware and OS. HD speeds continue to improve, as do the caching algorithms of the OS. This smells of premature optimisation to me.	[reply]
Re^4: Redirect data and Filehandle manipulation (STDIN x Disk IO) by mda2 (Hermit) on Jul 01, 2005 at 22:44 UTC
Really... I lost us time... it's don't functional with postfix content-filter (node updated). I getting all content into a scalar, considering memory/disk io speed, max message size and process limits (to don't use swap). Thank's by your attemption! -- Marco Antonio Rio-PM	[reply]
Re^4: Redirect data and Filehandle manipulation (STDIN x Disk IO) by mda2 (Hermit) on Jul 01, 2005 at 19:38 UTC
I'm using 5 dell servers (2 Xeon 3.2, 2GB ram, hds scsi, inet gbit), on normal traffic 1 G messages daily, but frequently we are target from spams/worms, and content filter is my task to improve performace... With normal usage of STDIN or temp file is equal, on hush hours it's the disk io is problem... I'm trying it before propose changes on content filter method... Perhaps this is exaggerates, but the profit called me attention. Other plataform changes are possible... :( -- Marco Antonio Rio-PM	[reply]