Thread: IT Guru response needed---

Well my background is in designing large online SQL databases, so I am 'slightly' guru in this area , but not in web traffic & network bandwith etc.

Initially I was thinking that the repeated pictures were stored again, taking up space, but on second thoughts the pictures are probably stored as URLs so a relatively short text string. Not sure how Attached pictures are stored on your server, but these would possibly take up significant data storage.

The bigger impact is the bandwith to transmit the extra pictures I would think. This extra bandwith would be making things slower for your web server and must be costing more (for the higher bandwidth) from your ISP. No doubt someone will be along soon to give a proper opinion on this.

I'm a CCNA, what response do you want?

read the post and offer your expert opinion,,,
yes, no or maybe

The question is, "Do images displayed in quoted text slow the forum down?"

The expert answer is yes, but not for the reasons, nor necessarily to the effect, your average user might think.

This is a little rushed, but hopefully explains the process:

Images are referenced by their URL in posts, so the quoted text would have a few extra bytes that have to be sent. Not a issue when serving a hundred people, can be an issue when serving millions. Image files on the other hand are quite a lot more bytes. Lots of people requesting large images/files at the same time would be an issue.

At the user's end, the first time the image file is downloaded it will be saved in the web browser's temporary cache (unless the cache settings have been changed), as are HTML, CSS and JavaScript files. Subsequent requests for these files will be served with the local cached copy.

Files will eventually get removed from the cache - maybe the expiry date is reached, the cache is cleared, the cache reaches its limit and the file is the oldest in the cache (first in, first out), or the browser finds out there's a newer version (modified date) on the server. In this case, the file is downloaded again.

So, a forum page might have three requests for a large image. The original post, and two replies quoting.

If the image is not in the browser's cache, it is requested from the server. If your ISP has a cache, it might send you their version, otherwise AURLO will serve the image file once.

The browser then displays the same image three times. If you've got a slow connection, you can often see the three instances of the image displaying line by line at the same time. Memory is a factor, as the GUI subsystem has to put everything together for rendering, so this could affect lower-end machines.

Our user clicks to page two, where the image is displayed in four more posts. Once again, the web brower checks if the image is in its cache, if not it requests it from the server. Again, an ISP level cache might serve a copy, otherwise AURLO serves the request.

Some people change their cache settings. My work is building websites, so all my web browsers are set to always request a server's files so I see exactly what the server will be serving.

I still only request the image once from AULRO, regardless of how many times it appears on the page. But, I have to download the image again for each subsequent page that requires that file.


In a nutshell, do quotes containing images affect forum speed?

Server-wise, most likely negligible. The real hit is serving large files. Compounded by lots of users requesting large files at the same time.

User-wise, depends on hard-drive space (often a factor in cache-size determination), memory (has to hold all the display data), CPU power. Also internet connection speed - if that 2mb image on page 1 isn't cached, you'll redownload it when it's quoted on page 2, 3...

This isn't only an issue for low-end machines, it can affect devices like PDAs, internet-enabled phones, etc.

x1 on what ben said...

isn't there a dba that looks after this stuff ?

What Ben said.
Is it a problem...probably not.
Is it needed, NO.
Run lean and mean....

I've only skimmed through what Ben posted and it is correct for pictures that are hosted on the aulro server. If the picture is hosted somewhere else, say photobucket or somewhere similar, then it will have no impact of the aulro server, as it is not hosting, therefore not sending the picture to your PC.