Maximum length of command line argument that can b

问题:

I am calling SQL*Plus from Linux C Shell:

sqlplus username/password @file.sql var1 var2 var3

If I pass a string as var1, how long can this string be?

Is it governed by the OS? In this case:

Linux version 2.6.9-100.ELsmp ([e-mail]) (gcc version 3.4.6 20060404 (Red Hat 3.4.6-11)) #1 SMP Tue Feb 1 12:17:32 EST 2011

Update: Empirical testing yielded the following results:

• A command line argument of 5200 characters gave the error, "Word too long."
• 1300 characters then produced the SQL*Plus error, "string beginning "(000796384..." is too long. maximum size is 239 characters."
• As soon as I got under 239 chars all was well.

I think I'll use sqlldr to overcome this.

回答1:

Try with: xargs --show-limits

Your environment variables take up 2446 bytes
POSIX upper limit on argument length (this system): 2092658
POSIX smallest allowable upper limit on argument length (all systems): 4096
Maximum length of command we could actually use: 2090212
Size of command buffer we are actually using: 131072

There is no limit per argument, but a total for the whole command line length. In my system (Fedora 15/zsh) its closer to 2Mb. (line 4).

回答2:

I came across "How long an argument list your kernel can take on the command line before it chokes?":

getconf ARG_MAX

which gives the following on my system:

131072