Does Google Analytics have performance overhead?

Question

To what extent does Google Analytics impact performance?

I\'m looking for the following:

• Benchmarks (including response times/pageload times et al)

Answer 1

Use FireBug and YSlow to check for yourself. What you will discover however is that GA is about 9KB in size (which is actually quite substantially for what it does) and that it also sometimes does NOT load very fast (for what reasons I don't know, I think it might be the servers "choking" sometimes)

We removed it due to performance issues on our Ajax Samples, but then again for us being ultra fast and responsive was priority 1, 2 and 3

Answer 2

You can host the ga.js on your servers with no problems whatsoever, but the idea is that your users will have the ga.js cached from some other site they may have visited. So downloading ga.js, because it's so popular, adds very little overhead in many cases (i.e., it's already been cached).

Plus, DNS lookups do not cost the same in different places due to network topology. Caching behavior would change depending on whether users use other sites that include ga.js or not.

Once the javascript has been loaded, the ga.js does communicate with Google servers, but that is an asynchronous process.

Hope this helps.

Answer 3

It really depends on the day. I'm just adding this to a blog. I'm in california, very close to their main data centers, on a fast low latency business DSL, on a overclocked i5 with plenty of RAM running a recent linux kernel and stable firefox.

here's a sample page load:

google-analytics alone added 5 seconds just of network download time... to get 15Kb!

You can see blogger.com served 34Kb in 300 mili seconds. That's 32x faster!

Also, look how the Red Line (which represents the onLoad event, meaning, there's no more script executing on the page and the so the browser can finally stops the loading indicators/spinings/etc) ... look how far to the right it is. that's probably 3seconds of garbage javascript processing that happened there. It's very uncommon for that line to be very far away from the end of the resources download bars. I'm done debugging this and it's 1/3 analytics fault, 2/3 blogger fault. ...one would think google stuff was fast.

Edit:

Some more data. Here's a request with everything cached. the above one was first visit.

I've removed the googleplus crap from above for two reasons, I was trying to see if they were playing some part on the slow onLoad event (they aren't) and because It is mostly useless.

So, With this we can see that the network time is the least of your worries. Even on a fast computer with modern software, the toll google analytics + blogger take on processing time will still dump your page load past 7s. Without the blogger, just check this very site, i'm seeing 0.5s of delay after resources are loaded and the red line kicks in.

Answer 4

Loading any extra javascript to your page is going to increase the download time from the client's perspective. You can ameliorate this by loading it at the bottom of your page so that your page is rendered even if GA is not loaded. I would avoid caching because you would lose the advantage of the client cache for your page. If the client has it cached from some other page, your page's request will be filled from the client itself. If you change it to load from your site, it will require a download even if the client already has the code (which is likely). Adding a task to your software processes to avoid loading the file from Google seems unwarranted for what may be an unnecessary optimization. It would be hard to test this since it would always serve up faster locally, but what really matters is how fast it works for your customers. If you decide to evaluate keeping it locally, make sure you test it from your home internet connection --- not the machine sitting next to the server in your rack.

Answer 5

There's no/minimal site overhead on the server side.

The HTML for Google Analytics is three lines of javascript that you place at the bottom of your webpage. It's nothing really, and doesn't consume any more server resource than a copyright notice.

On the client side, the page can take a little bit (up to a couple of seconds) of time to finish displaying a page. However - In my experience, the only bit of the page not loaded is the Google stuff, so users can see your page perfectly fine. You just get the throbber at the top of the page throbbing for a little longer.

(Note: You need to place your google analytics code block at the bottom of any served pages for this to be the case. I don't know what happens if the code block is placed at the top of your HTML)

Answer 6

The question was will Google Analytics cause your site to slow down and the answer is yes. Right now at the time of writing this Google-Analytics.com is not working so sites that have that in their pages won't load the pages so yes, it can slow down and cause your site to not even load. It's uncommon for google-analytics.com to be down this long which right now has been over 10 minutes, but it just shows that it is possible.