Re: [Nmh-workers] Large MH directories

[Tom Lane]

Ken Hornstein <address@hidden> writes:
>> Is this a bad idea? I'm mainly concerned about speed: Other than like
>> pick and scan on the whole folder, will anything else get very slow? I'm
>> using Fast File System on OpenBSD.

> We've been asked about this before; unfortunately, with the current (n)mh
> design, it's just going to suck.

> A bit of an explanation: right now, pretty much every nmh program that
> wants to interpret a folder calls folder_read(). folder_read() does
> a readdir() on the ENTIRE folder.  It does NOT do a stat() on every
> file, but if you have 600k files in a single directory, that's just
> going to take some time.

FWIW, I have not noticed any real performance problems with folder sizes
in the range of 10K-50K messages.  I try to keep my folders under 100K,
not because performance falls off a cliff but because I begrudge the extra
space for the message number in scan listings.

It may or may not matter that I use exmh not direct nmh commands.
exmh seems to cache the scan output, but then again it adds a lot of
its own overhead.

                        regards, tom lane