The issue: Swiper is a great search method. However, for large files, it takes very long from search process invocation to be actually able to enter the search query. I added to a bug report on Github for this issue.

Until this issue is fixed, I have to think about a workaround.

What are the alternative search methods? Before Swiper, I was using incremental search ( isearch-forward ). It might be the case that search-forward is even faster. But I won't settle for less than isearch. A different alternative would be occur . For now, standard incremental search is sufficient for large files.

So: how about switching search method of C-s depending on the number of lines of the current buffer? Small files gets the advanced Swiper search, large files gets the basic incremental search.

Let's do it.

Deeper Analysis of the Issue

To prevent me from chasing the wrong things, I did a profiler-run:

Function CPU Samples % - command-execute 34706 98% - call-interactively 34706 98% - swiper 34618 98% - apply 34618 98% - compiled 0x156eb5d 34618 98% - swiper--ivy 34618 98% - swiper--candidates 32825 93% - replace-regexp-in-string 88 0% apply 24 0% + funcall 8 0% + ivy-read 196 0% + byte-code 49 0% + minibuffer-complete 31 0% + execute-extended-command 8 0% + ... 452 1% + yas--post-command-handler 16 0% + timer-event-handler 6 0% + redisplay_internal (C function) 4 0%

OK, the culprit seems to be swiper--candidates .

Then, I had to find the sweetspot. How many lines does a buffer have until Swiper gets slow? For this purpose, I did some very basic performance measurements from the invocation of the search command until I am really able to enter my search query:

Lines of Buffer Seconds until Searching 48000 20 30000 8 14000 1 6700 1

It seems to be the case at approximately 20,000 lines. Here, swiper-20160124.429 from elpa gets slow on my intel i5 with GNU Emacs 24.4.1 on Debian GNU/Linux.

Now we have found out more about the background, let's continue with coding our workaround.

Implementing Buffer-Sized Search Method Switching

As an Elisp amateur, I always get a bit nervous when I have to actually generate Elisp code. But this should be an easy one even for me.

Counting lines of a buffer works quite fast in large files:

(count-lines (point-min) (point-max)))

This is how the definition of two different search methods looks like:

(global-set-key "\C-s" 'swiper) ;;fancy search ;; ... OR ... (global-set-key "\C-s" 'isearch-forward) ;;normal search

This is my workaround that switches the search method according to the number of lines in the current buffer:

(defun my-search-method-according-to-numlines () "Determines the number of lines of current buffer and chooses a search method accordingly" (interactive) (if (< (count-lines (point-min) (point-max)) 20000) (swiper) (isearch-forward) ) ) (global-set-key "\C-s" 'my-search-method-according-to-numlines)

Using Oleh Krehel's Method

While I was working on my workaround above, Oleh Krehel answered to my GitHub issue with his solution to the same issue:

(defun ora-swiper () (interactive) (if (and (buffer-file-name) (not (ignore-errors (file-remote-p (buffer-file-name)))) (if (eq major-mode 'org-mode) (> (buffer-size) 60000) (> (buffer-size) 300000))) (progn (save-buffer) (counsel-grep)) (swiper--ivy (swiper--candidates)))) (global-set-key "\C-s" 'ora-swiper)

This is clearly more elegant than mine. He checks on buffer size, distinguishes Org-mode buffers from the rest, and uses other (advanced) search methods such as counsel .

Unfortunately, I got issues with counsel-grep and his swiper command:

(swiper--ivy (swiper--candidates)) results in (wrong-type-argument stringp (#( followed by a string containing the whole buffer.

counsel-grep results in Symbol's function definition is void: ivy-set-display-transformer . I found #404 but could not resolve the issue with it.

Another helpful comment by Oleh and I found out that most of my Emacs packages were /very/ outdated due to a misconfigured package-archives setting. After a huge update session, counsel as well as swiper are doing great!

The performance boost is astonishing!

There is a reddit-thread on this topic.