RE: Question about dired-do-find-regexp and xref-collect-matches

[Drew Adams <drew.adams@oracle.com>]

> I noticed that marking files in Dired and using "A"
> (dired-do-find-regexp) to search them was extraordinarily slow. Going up
> a level to the parent directory and only marking the child directory,
> the search was nearly instantaneous. But that meant I had to search all
> the files in the child directory.
> 
> I suspected it was something to do with fish, and indeed setting
> shell-file-name to "/usr/bin/bash" sped it up a little -- but that's a
> bug report for another day.
> 
> While poking around I also noticed that dired-do-find-regexp calls
> xref-collect-matches once per marked file. That means a full find+grep
> call for each file, when a single find+grep call (or even just a single
> grep call!) would do the trick.
> 
> The search hits are collected as:
> 
> (mapcan
>  (lambda (file)
>    (xref-collect-matches regexp "*" file
>                          (and (file-directory-p file)
>                               ignores)))
>  files)
> 
> But the second argument to `xref-collect-matches' can be a
> space-separated string of file names -- wouldn't it be easier just to
> call `xref-collect-matches' once?

Meanwhile (fortunately), you can still use
`dired-do-search' (which used to be bound to `A').

If that wasn't "extraordinarily slow" for you
before, it still might not be.  Maybe try it.