Phil Pennock wrote:
> On 2008-01-04 at 16:07 -0800, Michael G Schwern wrote:
>> Of course, as Peter insinuated, I'm sure by now it's been rationalized as a
>> "feature".
>
> In large environments, having everything always locally available on
> local disk is fairly recent, with cluster management systems etc. NFS
> is still common.
>
> I'm in an environment where I work hard to keep my shell from having to
> go scan places in random NFS mounts, including syncing two-line shell
> wrappers to a special bin-dir within my NFS homedir since then at least
> if the dir cache gets flushed it's flushed by me, not by dint of someone
> somewhere always updating something. Heck, they go into aliases so the
> commands are only a backup for when scripts are invoking the
> command-name expecting it to be in the path. Without this grotesque
> hackery, regular work becomes nightmarish during the business day.
>
> Caches which don't cache negative results don't tend to be effective
> caches. The question is whether or not a cache should be used at all.
>
> So the feature is useful in some environments but probably shouldn't be
> the default these days. People in such environments can learn to use it
> and people whose idea of Unix is a single modern computer with local
> disks can't conceive of set-ups different from their own and whine a
> lot. Bloody Linux users.
>
> (zsh has a similar feature)
I think you've veered off into a wholly different and more subtle hate.
We're not talking about not caching negative results, as in "there was a
command called 'foo' at /path/to/foo and now it's gone. I didn't find it the
last ten times I scanned PATH but maybe the eleventh will work!" For that,
caching the time of the last negative result would be handy, then you could at
least do a progressive back off. Even so, it only effects performance when
you try to run the missing command.
We're talking about "there was a command called 'foo' at /path/to/foo and now
/path/to/foo is gone. Well, that's the best I can do, I give up. You're
welcome to blow away THE ENTIRE CACHE and I'll rescan EVERYTHING for you. k
thx bye!"
I would think that would generate maximum hate in a slow environment.
And, of course, WHY IS THIS STILL THE DEFAULT?!
--
I am somewhat preoccupied telling the laws of physics to shut up and sit down.
-- Vaarsuvius, "Order of the Stick"
http://www.giantitp.com/comics/oots0107.html
