Alex said:
I don't get it. It's just text. Links. They're not updated real time. How can that slow the forum down? Does it need and extensive database search or something?
I can tell you the difference between 0, 50, and 100 posts displaying on my forum (same software), although the hardware and software environments are different. I have less concurrent users (150 or so), but have about 1.5 million posts, and I'm on a shared server while Shane has mentioned this was on a dedicated. I'll run each 10x average the result.
With 0 posts showing, "Page created in 0.045 seconds with 8.1 queries."
With 50 posts showing on the bottom, the average nearly triples to 0.013, with the queries going up to 9.2.
With 100 posts, it's quadruple the original to 0.201, basically the same number of queries as 50 posts.
As you can imagine, as your volume increases, response time gets exponentially slower with multiple requests to the same hardware (if you've ever written two files at once on your computer, it's not just double the time required, it's more like 2.5x to account for the overhead switching between the two data streams). Now try reading/writing 300 at once. So what was .04 seconds becomes maybe .1 seconds with load, but .2 seconds will become 5 seconds as you approach the limitations of your system and what was concurrent before becomes lots of queuing.
Each row for each post as you see, requires pulling back rows from two tables and matching them together (you'll see that it shows which thread it originates from, which is stored in another table). Additionally, the actual page page creation time for each post is probably a small fraction of the total server response time, but note that each requires a date/time calculation for each instance you see a date/time since it is calculated based on what you input as your time zone.