Table Optimizing

[USAPatriot]

A few questions:

The forum seems to suffer from slowdowns on a regular basis. I only have a few dozen users. I use the Admin control panel to optimize and it helps but only for a short while. When I go back in, there is again "Overhead". What exactly is overhead and how/why is it affecting the forum? Under scheduled tasks, can the script that runs the optimization be run hourly or whatever to keep it under control? Or is there something else going on that's causing the delays? Thanks. -Rod-

[USAPatriot]

Cust Serv get outsourced this week?

[Steve Machol]

From the forum rules:

http://www.vbulletin.com/forum/showthread.php?t=42918

Please wait a reasonable amount of time before bumping posts. For style changes and general 'how-to' questions this should be 24 hours. For specific troubleshooting issues, use 12 hours as a guideline.

I could not find a useful definition of 'overhead' on the MySQL site. However in my experience this is just 'empty space' in a table which can be fixed by optimizing it. I have never seen this responsible for 'slowdowns' and think that this is more a symtom of a server issue rather than a cause.

Are you on a shared or dedicated server? have you installed any hacks or plugins?

The bottom line is that there is no reason for this to happen this freqquently on a well-managed and optimized server.

[USAPatriot]

From the forum rules:

http://www.vbulletin.com/forum/showthread.php?t=42918

I could not find a useful definition of 'overhead' on the MySQL site. However in my experience this is just 'empty space' in a table which can be fixed by optimizing it. I have never seen this responsible for 'slowdowns' and think that this is more a symtom of a server issue rather than a cause.

Are you on a shared or dedicated server? have you installed any hacks or plugins?

The bottom line is that there is no reason for this to happen this freqquently on a well-managed and optimized server.

Well, the term "Overhead" is being used by VBulletin itself. It's right there in the AdminCP's optimizing screen. One can assume that the authors of that page had some inkling of what they were doing and what it meant. Or so we can hope. Shared host, no hacks or plugins. The phenomenon actually is observable - if I optimize the system speeds back up, very noticably. Lags can run from 2-3 seconds and then drop to almost nil. That's no coincidence. -Rod-

[Marco van Herwaarden]

What is reffered to as Overhead in your AdminCP is what MySQL call Data_Free (http://dev.mysql.com/doc/refman/4.1/...le-status.html)

Data_free
The number of allocated but unused bytes.

When new data gets written to a table/index (actually when it gets written to the OS-File), a block on the disk will be allocated for it if there is no more free space in the table. How blig this block is, depends on MySQL settings and OS. Not sure but i think deleted rows also show up as free space until reused.

The Overhead column indicated how much free space is still available within the currently allocated file.

Optimizing tables can have an effect on performance, but the performance is not related to the Overhead column.

[Steve Machol]

Well, the term "Overhead" is being used by VBulletin itself.

A term which it gets directly from MySQL. Believe it or not, vB did not make up that term. You will also see it in phpMyAdmin.

[USAPatriot]

Well, regardless, on to the second part of the question: Can I have the Scheduled Tasks run whatever script is doing the optimizing? Unfortunately optimizing all the tables is not the default selection, at least not in the AdminCP panel. It'd be nice if it would just do it once an hour whether it needs it or not and without me having to wait until the board slows down to do it manually. -Rod-

[Steve Machol]

Yes, however this would require you to write a cussttom script to do this.

[USAPatriot]

Yes, however this would require you to write a cussttom script to do this.

That kills that idea. Thanks anyhow. -Rod-