I had a feeling that some of my scripts dealing with a large number of
files had become significantly slower lately, but I haven't been sure.
Today I took some time to find out whether or not I was only imagining
things.

The results of my experiments seem to indicate that something has changed
relatively recently with regards to extended globbing. I am using a Mac for
the moment, and I have currently have two versions of Zsh installed: 5.0.5
and 5.2. See below for my test run. As you can see, I do some globbing in a
fairly large directory (2.4 Gb and 231748 files). Notice that with a
complicated glob pattern, assigning matching files to an array takes about
33 seconds under 5.2, whereas the same assignment takes about 6 seconds
under 5.0.5. The speed difference with a less complicated glob (**/*) is
negligable.

Is there some change that could explain this difference, and is there
something to do about it? The difference in speed is so large that it
affects scripts that I run regularly quite a lot.

The test run, I hope it's self explanatory. All commands are run from the
same directory.

% print -l **/* | wc -l
231748

% du -sh .
2.4G .


% /usr/local/bin/zsh --version
zsh 5.2 (x86_64-apple-darwin14.5.0)

% /usr/local/bin/zsh -f
% setopt EXTENDED_GLOB

% date; myfiles=(**/*); date
Sun Feb 28 20:58:12 CET 2016
Sun Feb 28 20:58:27 CET 2016

% date;
myfiles=((#i)**/*~(|*/)(build|target|node|node_modules|.idea|*.min.js|*.iml|TAGS)(|/*)(-.D));
date
Sun Feb 28 20:58:39 CET 2016
Sun Feb 28 20:59:12 CET 2016


% /bin/zsh --version
zsh 5.0.5 (x86_64-apple-darwin14.0)

% /bin/zsh -f
% setopt EXTENDED_GLOB

% date; myfiles=(**/*); date
Sun Feb 28 21:00:43 CET 2016
Sun Feb 28 21:00:56 CET 2016

% date;
myfiles=((#i)**/*~(|*/)(build|target|node|node_modules|.idea|*.min.js|*.iml|TAGS)(|/*)(-.D));
date
Sun Feb 28 21:01:04 CET 2016
Sun Feb 28 21:01:10 CET 2016