Fasd: Slow

I suspect the main reason is that fasd is called twice as an executable in preexec. This overhead can be minimized if fasd is sourced by zsh (source =fasd should work in zsh).

Also, to make the comparison more fair, you can tell fasd and z to use the same database, since the fasd just use z's data format.

I looked at the code and it seems possible to condense two executable call into one. I'll play around with the code when I have time.

Any updates on this? I would love to use fasd, but right now it's just too slow.

inlining the --sanitize sed regex's into the function also helps somewhat, but it's still very slow.

im having slowdowns too using simply: eval "$(fasd --init auto)" in .bash_profile.

@sindresorhus profiling sounds interesting. mind sharing how you do that?

@wamatt It's in the issue text.

I am also observing that fasd slows down my shell significantly.
I have eval "$(fasd --init auto)" in my .zshrc.

zsh 5.0.8 (x86_64-apple-darwin14.3.0) on OSX.

$ zprof

num  calls                time                       self            name
-----------------------------------------------------------------------------------
 1)    6         194,36    32,39   92,69%    194,36    32,39   92,69%  _fasd_preexec
 2)    6           5,96     0,99    2,84%      5,96     0,99    2,84%  _powerline_get_main_keymap_name
 3)    6           5,29     0,88    2,52%      5,29     0,88    2,52%  _powerline_set_true_keymap_name
 4)   24           2,40     0,10    1,15%      2,40     0,10    1,15%  url-quote-magic
 5)    6          11,82     1,97    5,64%      0,57     0,09    0,27%  _powerline_set_main_keymap_name
 6)    6           0,30     0,05    0,14%      0,30     0,05    0,14%  zle-line-finish
 7)    6           0,27     0,05    0,13%      0,27     0,05    0,13%  zle-line-init
 8)    6           0,19     0,03    0,09%      0,19     0,03    0,09%  omz_termsupport_precmd
 9)    6           0,18     0,03    0,09%      0,18     0,03    0,09%  omz_termsupport_preexec
10)    6           0,09     0,02    0,04%      0,09     0,02    0,04%  _powerline_set_jobnum
11)    6           0,06     0,01    0,03%      0,06     0,01    0,03%  omz_termsupport_cwd

-----------------------------------------------------------------------------------

 1)    6         194,36    32,39   92,69%    194,36    32,39   92,69%  _fasd_preexec

Still slow in 2017 :)

The slowdown was the first thing I noticed after installing fasd, so I did some profiling too.

With my default ~/.zshrc

$ time (for i in {1..20}; do zsh -ic 'exit'; done)

================
CPU 87%
user    1.913
system  0.880
total   3.207

With z: source /usr/share/z/z.sh

$ time (for i in {1..20}; do zsh -ic 'exit'; done)

================
CPU 87%
user    1.837
system  0.970
total   3.213

With fasd: eval "$(fasd --init posix-alias zsh-hook zsh-ccomp zsh-ccomp-install zsh-wcomp zsh-wcomp-install)"

$ time (for i in {1..20}; do zsh -ic 'exit'; done)

================
CPU 83%
user    2.207
system  1.123
total   3.993

So z adds < 1 ms, while fasd adds 39.3 ms.

I don't know if this is still relevant, but using this snippet of code fixes the problem for me:

eval "$(fasd --init posix-alias)" # Anything you want enabled BUT zsh-hook

_fasd_preexec() {
    { eval "fasd --proc \$(fasd --sanitize \$2)"; } &|
}
autoload -Uz add-zsh-hook
add-zsh-hook preexec _fasd_preexec

from here
I suspect the main reason is that fasd is called twice as an executable in preexec. This overhead can be minimized if fasd is sourced by zsh (source =fasd should work in zsh).

Is that = in the source statement meaningful?

I don't know if this is still relevant, but using this snippet of code fixes the problem for me:

eval "$(fasd --init posix-alias)" # Anything you want enabled BUT zsh-hook

_fasd_preexec() {
    { eval "fasd --proc \$(fasd --sanitize \$2)"; } &|
}
autoload -Uz add-zsh-hook
add-zsh-hook preexec _fasd_preexec

I don't see any performance difference if I go with the output of zsh --init zsh-hook which is below.
Not sure if it's relevant but I save the below snipped in a cache file and then source that instead of doing an eval over the output.

# add zsh hook
_fasd_preexec() {
  { eval "fasd --proc $(fasd --sanitize $1)"; } >> "/dev/null" 2>&1
}
autoload -Uz add-zsh-hook
add-zsh-hook preexec _fasd_preexec