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Groups > gnu.bash.bug > #14487

Re: Unexpected delay in using arguments.

From Bob Proulx <bob@proulx.com>
Newsgroups gnu.bash.bug
Subject Re: Unexpected delay in using arguments.
Date 2018-08-14 15:50 -0600
Message-ID <mailman.5110.1534283444.1292.bug-bash@gnu.org> (permalink)
References <CAFra36j=UuqHv2Spp26ebAW0dRW+KsgNS21hZJrwuku9QUayWw@mail.gmail.com>

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I followed along through the script:

>     m=20000
...
>     test1() { ...

Eventually I got to this line:

>       set -- $(seq $m)

At that line I see that bash must allocate enough memory to hold all
of the numbers from 1 through 20000 in memory all at one time.  That
is very inefficient.  That is at least 100K of memory.

  $ seq 20000 | wc -c
  108894

Of course I assume this is only a proxy simpler reproducer for the
actual problem program but just the same it is almost always possible
to refactor a program into a different algorithm that avoids the need
to enumerate so many arguments in memory.  I suggest refactoring the
program to avoid the need for this memory stress.

Bob

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Re: Unexpected delay in using arguments. Bob Proulx <bob@proulx.com> - 2018-08-14 15:50 -0600

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