Re: [exim-dev] [Bug 474] ACL condition to unset a variable

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Author: Philip Hazel
To: bug474
CC: exim-dev
Subject: Re: [exim-dev] [Bug 474] ACL condition to unset a variable
On Wed, 21 Feb 2007, kjetilho@??? wrote:

> ------- Comment #5 from kjetilho@??? 2007-02-21 18:31 -------
> I'm sorry, but I don't see why this is worthwhile. you can set the variable to
> "" to save memory, so the only thing gained by unsetting variables is that they
> don't have to be listed in the queue file. so we save perhaps 32 bytes of disk
> space for each such variable.

On Wed, 21 Feb 2007, bugzilla.exim.simon@??? wrote:

> ------- Comment #6 from bugzilla.exim.simon@??? 2007-02-21 20:54 -------
> Surely this is the point of unsetting variables?

(1) Setting a previously set variable to "" is unlikely to save memory,
because the old value's memory probably won't be re-used.

(2) Unless you use a zillion variables, saving 32 bytes of queue file
for each variable is hardly going to affect anything.

(3) The original patch that marks the variable "unset", without fiddling
with the tree, would in any case achieve that.

(4) I cannot see the point of implementing a complicated and tricky
algorithm to actually remove nodes from the tree. I can't see any
benefit at all, and in any case if there were any benefit it would be
for a small number of users.

Philip Hazel            University of Cambridge Computing Service
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