find function slower since 1.9.0, especially in chrome

[ktmitton@…]

I noticed when selecting a large array of elements (in my case 11,000+), the jQuery find function would perform much slower in 1.9.0 than in previous versions of jQuery. Looking into the code, it looks like the function was rewritten to use the jQuery.unique function, which was actually mapped to Swizzle.uniqueSort.

It turns out the actual sorting part of the function:

results.sort( sortOrder );

is where the slowdown occurs. I tested in Firefox and IE as well, and the slowdown wasn't as noticeable, but in chrome this added 5-10 seconds to the find.

I created a jsFiddle test ​http://jsfiddle.net/E6gPN/6/ that creates 12,000 options, runs the find, and outputs the amount of time it took to execute the find.

[dmethvin]

1) In what kind of situation do you have 11,000 DOM elements?

2) Looks like it's unnecessarily going through a unique sort in .find() since for that simple case the results will already be sorted.

[anonymous]

Replying to dmethvin:

1) In what kind of situation do you have 11,000 DOM elements?

2) Looks like it's unnecessarily going through a unique sort in .find() since for that simple case the results will already be sorted.

1) I know it sounds ridiculous, but I actually do have a few select boxes that are populated with that many options, and I'm not permitted to change that.

2) Yeah, that's what I found. If I had to guess, the unique function call probably just seemed like a nice way to trim down the original code in the function, and the sort probably seemed negligible to the person who rewrote find, and like you said doesn't really change anything.

[Dave Methvin]

Fix #13349. No need to sort simple .find() cases.

Changeset: 1bbe2b1ded24edf7bf7b18512aff4148591803da

[Dave Methvin]

Fix #13349. No need to sort simple .find() cases.

Changeset: a5c33fe1f7872a20267ff69905561c8cc55fe3c1

[nelumirea82@…]

Excellent site - do keep up the good work.