Forum Access Issues – Explanation & Fix Update

[Lee Roberts]

Hi everyone,

Some of you will have noticed regular periods where the forum has become completely inaccessible, throwing up database errors like "Unable to connect to database" and/or similar. I wanted to take a moment to explain what’s been going on behind the scenes for quite some time now and what I’ve done to get things back on track.

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The Problem: Session Table Overload

The issue has been caused by the session table in our forum's database becoming completely full.

When you visit the forum, your session (your presence) is logged in that table, it’s what keeps you logged in and tracks general activity. The problem is when that table fills up, new visitors can’t be logged, and as a result, the database throws an error and the forum locks up for everyone.

Now, this wouldn’t usually happen, there’s a maintenance system in place that clears out old session data (specifically sessions that are over 1 hour old). But here’s the catch…

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Why This Keeps Happening

The vBulletin forum software doesn’t run its scheduled tasks in the same way a server like Windows or Linux does.

Instead, vBulletin relies on a kind of "pseudo-cron" system, Basically, every time someone visits the site, a little bit of code in the page footer quietly triggers the task manager in the background (server side).

That manager then checks what scheduled tasks need to run. Some tasks are set to run daily, some hourly, and some like the one that clears the session table, depend on frequent human visits to keep up.

But when the site is quiet… those tasks fall behind.
Fewer visitors = fewer chances for the system to clean itself. So over time, the session table gets full — and then we’re locked out again.

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Fixes Implemented

I've now taken two key steps to deal with this properly:

DNS level Managed Challenges

After investigating the traffic logs, it became clear that we were being flooded with automated traffic, likely bots or abuse scripts, that were swamping the session table by visiting the forum in massive numbers.

So, I set up Cloudflare’s managed challenge system at DNS level, which in just 24 hours:

• Blocked or challenged 75,000 visits from Singapore
• Stopped 45,000 visits from Brazil
• And filtered out another 75,000+ visits from other parts of Asia

This has significantly reduced the load and helped prevent the session table from getting hammered.

Server-Level Scheduled Task (Real Cron)

I’ve also implemented a proper server-side scheduled task (cron job) that runs independently of site traffic.

This new task now:

• Runs on the hour, every hour
• Clears out any session data older than one hour (if your inactive for this amount of time or more, you will be logged out)
• Ensures the session table is always kept under control — whether the site is busy or not

This bypasses the vBulletin system entirely for this particular issue and ensures the session cleanup happens reliably, every time.

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What Happens Next

These changes should stabilise the forum and keep things running smoothly again. I’ll be continuing to monitor things closely, this has been a long time problem I know, however I’ve got more long-term upgrades coming, including a proper migration to a new platform, I’ll share more on that soon.

Thanks as always for your patience, and for sticking around. This place is still ticking, and I’m doing everything I can to keep it that way.

Catch you all soon,
Lee

[Muzzer]

You lost me on the first sentence but it's great to know you seem to be on top of it! Hope it stays that way - appreciate your efforts to keep it running.

[Neale]

Well done, Lee. I look after another model engineering-related web site and regularly get updates on how many of these nuisance probing connections are getting blocked. I can't imagine how much internet traffic is just this "noise' as it must be happening on just about every web site on the internet.

[Lee Roberts]

You lost me on the first sentence but it's great to know you seem to be on top of it! Hope it stays that way - appreciate your efforts to keep it running.

Hey @Muzzer,

Haha, yeah sorry mate I did go a bit full nerd on that first sentence didn’t I Appreciate you sticking with it though, and cheers for the kind words.

I've got a much better handle on it now, so fingers crossed that’s the last of the connection errors for a while. Plenty more improvements to come and underway too, slow and steady, but we're moving!

Well done, Lee. I look after another model engineering-related web site and regularly get updates on how many of these nuisance probing connections are getting blocked. I can't imagine how much internet traffic is just this "noise' as it must be happening on just about every web site on the internet.

Hey @Neale,

Cheers mate I really appreciate it, yea you’re spot on, the sheer volume of garbage traffic is mind blowing at times isn’t it...

It’s reassuring to hear you’re seeing similar patterns too, makes you realise it’s not just “us” being unlucky. I’ve got some longer term ideas to harden things up further (especially once we’re on the new platform), but this should hopefully keep the gremlins out for now...

Always good to hear from someone who knows the pain, thanks again!