Has the bottleneck in board performance been identified?

I realize there’s no money to do anything about it anyway, but out of curiosity, has the performance bottleneck been identified? Is it memory, CPU speed, or network bandwidth, or what?

It’s mainly the slowdown when getting data out of the database to gather the HTML that will form the webpage constituting an SDMB thread.

I’ve had little experience with databases; is the data retrieval slow because their is not enough memory to cache frequently requested data and it has to access a disk?

I don’t know the exact details, but the main problem is that searches have to read a huge amount of data. It’s probably a little bit of both - faster disks would help, but also being able to cache more data in memory.

My guess is that more memory to cache would always be faster than even the fastest disk. Of course, if the database program is already is using the largest RAM cache that it is designed to use, adding more RAM would be a waste.

Has the MySQL server been tuned? You can significantly increase performance by adjusting the size of various memory buffers from the default values to match the amount of RAM on your system. It would be a shame if the server is grinding to a halt at 32 megabytes when you have a gig RAM to take advantage of.

Here’s a page from the MySQL manual on tuning: http://www.mysql.com/doc/en/Server_parameters.html

Also, just as a quick fix, the options on the search page can be restricted a bit more. Remove “Search all Open Forums” from the forum list and set “Search titles only” to the default instead of “Search entire posts”. That might make a dent in search overhead.

When we had the earlier version of vBulletin, we did used to have Search set so that you could only search one forum at a time, but when we switched to this version of VBulletin, back in February/March, it was left at the default “Search all open forums”. No idea why.

I’ve found the “search all open forums” option useful, and would like to continue having that option. I could see making it not the default, though.

Is Jenner correct that the board using MySQL? Has someone checked that page he referenced?

Yes the board uses MySQL. jdavis the administrator has tuned the database to improve performance.

So, since the database had been tuned, is it pretty much been determined that the bottleneck is RAM?

Revtim, did you read my post above? It’s partly due to physical memory and partly due to disk speed. Plus there are probably other reasons that jdavis would know about.

Of course I read it. Do you understand that if one can avoid hitting the disk at all, like when the information requesting is in RAM, that is doesn’t matter how fast or slow your disk is? Do you also realize that no matter how fast a disk is, RAM access will be quicker?

I’m only trying to make sure that the true bottleneck is identified, no need to get snippy.

Now that we’ve determined that the MySQL database has been tuned, I think it’s safe to assume that it’s using all available RAM. Ignoring the possibility that because of design it cannot use any more RAM, and that the server isn’t already maxed out on RAM, it seems the best solution to speeding up the board is to get more memory for the server.

Memory is cheap nowadays. Has anyone made a cost estimate to adding some RAM? If it’s just a few hundred bucks, that could probably be raised simply through donations using the Amazon Honor System or selling a few special “Straight Dope” mugs with Cecil’s signature for 20 or 30 bucks each.

Some servers have a physical limit on how much RAM they can use. The SDMB server may be at that limit.
If there was a cheap and easy way to increase server performance, the Chicago Reader would already have done that.
The Chicago Reader has said in the past that they will not accept donations.

A couple of other things I should mention:
By profession, I personally am a database administrator, so yes I understand the difference between reading data cached in memory and physical disk I/O.
jdavis who manages the SDMB server is an experienced UNIX system administrator. He has posted in the past that there is no cheap and quick fix for the performance problems on the server. The server has been upgraded twice IIRC since I’ve been a member and jdavis has said that the hardware upgrades were met almost immediately with increased demand.
As is mentioned in the FAQ, different fund-raising methods have been suggested ad nauseam in the past in this forum.

Yah, every time Jerry the Tech God waves his thunderbolts and upgrades the server, the demand just keeps pace with it. Ultimately we’d need a server the size of Google’s. :smiley:


I’m not sure I even know what a “terabyte” is. Is it like a bazillion-byte? :smiley:

And even so:

I moderate another forum that had the same issues (We have around 75,000 members). They did a forum prune, went through the forums & bumped important posts then pruned out maybe 30,000 old posts. It brought the board back to it’s usual fun self. This created a smaller database. But most of the posts there were the same thing day after day & it’s not like that with the SD where the info changes daily.

A terabyte is 1000 gigabytes, or 10[sup]12[/sup] bytes (strictly speaking, 1024 gigs, or 2[sup]40[/sup]). I believe that the next step after tera- is peta-. I’m not sure what the progression is after that, but I think that exa- is 10[sup]24[/sup], and somewhere along the line the Marx brothers get involved.

I was wondering… What type of connection connects the server to the outside world?

Please understand I am not complaining about SDMB’s performance; it is such a wonderful resource I’ll take whatever speed the hamsters can manage without blistered paws and tiny, furry heart attacks.

But I just noticed something in the last few minutes. For at least an hour, I have had 3 or 4 windows open, each with a different SDMB topic or forum. All have been extremely slow to update when requested, whether display, preview, post, etc. – and earlier today it took about 15 minutes to post a new thread.

But just a few minutes ago, about 11:00PM (+/-5 mins) Chicago time, everything sped up to (tolerably) normal. Suddenly. All threads, all windows, all functions.

Now I am intimately sensitive to my computer’s, brower’s, and ISP’s needs and performances, and I am 95% sure the speedup was on or near SDMB’s end. (Other simultaneous windows showing non-SDMB URLs were fast-normal.) Does this observation help in any way to trace the problem to origin? For example, was there a heavy process running that stopped around 11PM tonight?

Hope this is useful.

Y’know, I’ve heard this a couple of times now from different people and I don’t understand it. Are you saying that people are refusing to sign up because our boards are occasionally slow? Or that members would post more if the boards were faster? It doesn’t seem like things are that bad.

I guess it just doesn’t seem like server speed is that much of a limiting element WRT membership or frequency of posting. Maybe I’m not understanding the issue. Newbie and all. :slight_smile: