WordPress MU

Hi,

Can someone please explain what the flag "WP_USE_MULTIPLE_DB" is for, and how its should be used and configured?

It was added in http://trac.mu.wordpress.org/changeset/81

Thanks,
Martin

It's used when you need to run wpmu off more than one database. It's not fully implemented so unless you have more than 10K users or are running on a dedicated machine I wouldn't worry with it.

Other than wp.com, very few people run wpmu off of more than one db.

When you say off more than one database, does this mean that its used to partition the blogs across multiple databases or it is used to support multiple hosts served by the same installation?

It's meant to spread users among several databases. However, like I mentioned, it's a real pain to get running at the moment.

Ok, thanks. That's all I need to know right now :)

Documented on http://codex.wordpress.org/WPMU_Internal_Flags#WP_USE_MULTIPLE_DB

We're in the middle of getting it running, and I would say that yes, it is an issue when you're on shared hosting and have either db limitations and have to consider the limitations in phpMyAdmin. :( Something I'm dealing with at the moment - I can't even get it to make a backup, my db is so big.

So yeah, it's there and not fully implemented OR documented. This is one of those "on your own" things when dealing with alpah (are we even in beta yet?) software.

When we get it working (because we have to at this point) I'll be sure to let everyone know how.

So yeah, it's there and not fully implemented OR documented. This is one of those "on your own" things when dealing with alpha (are we even in beta yet?) software.

When we get it working (because we have to at this point) I'll be sure to let everyone know how.

One of the few ways the community can help is by helping build the consolidated documentation set. I'm trying to help where I can in this respect. I hope you agree that it is useful.

As long as it's correct. :)

As long as it's correct. :)

Heh. No entirely true... that's the point of the wiki: anyone in the WPMU community can change it to add a comment in the right place, anyone can rearrange it so it reads better, and anyone can create new topics that synthesize previously unconnected thoughts.

Once we have trained each other to use the wiki we collectively grow and garden topics, each able to make things just a "little better".

Its about realising that what you right doesn't have to be complete, just a little useful. And it matters little once everyone looking at it realises that it is a malleable form that is collaboratively shifted to reflect the consolidated conclusion of conversations.

Forums such as this, well, the lack of being able to "garden together" really shows up. This comment of mine, for instance, is buried under "WP_USE_MULTIPLE_DB" which is a response to your comment but nothing about the topic subject.

If this was on codex, any person who saw the comment could refactor the text such that it was in the most appropriate place.

Our current advice for newcomers is to "search", which is fine if that newcomer can 1) find the mu search box, 2) be bothered with the extra three clicks 3) know what to search for. Further, that newcomer has currently no opportunity to contribute by helping to restructure what was found other than by creating yet another forum posting.

A problem with all communities is the gap between the existing users and the new ones. Wikis help close that gap by ensuring the fidelity of the content and the meaningfulness of the link names. Fidelity is driven by collective gardening and right-place commenting and meaningfulness is driven from the URL space (slug, in WP terms).

Anyhow, that's enough of my rambling here. I'm going to copy this text into the WPMU Codex so that we can jointly improve on this text in http://codex.wordpress.org/WPMU_Forums

I'm figuring out how to make separate DB for each blog. It seem to catch my eyes that WP_USE_MULTIPLE_DB option is there... however it's not really what I thought because according to this http://codex.wordpress.org/WPMU_Internal_Flags:

WP_USE_MULTIPLE_DB

WP_USE_MULTIPLE_DB is used when you need to run wpmu off more than one database. It allows the administrator to spread users across several databases.

It's not fully implemented so unless you have more than 10K users or are running on a dedicated machine its best not to worry with it.

Other than wp.com, very few people run wpmu off of more than one db.

Unfortunately it didn't state how to deal with it. Perhaps Automatic wants to keep that for their own wp.com only?

@binh
See (not a single db per blog but similar):
HyperDb - http://codex.wordpress.org/HyperDB
MultiDb - http://mu.wordpress.org/forums/topic.php?id=8029
WPMUDev - http://premium.wpmudev.org/project/Multiple-Databases

With the last two you could actually have a single db per blog if you wanted to.

Thanks,
Andrew

I'm removing binh's spammy keyword rich links from his posts. Apologies for threads resurfacing.

Thanks, Donncha. No apologies needed. Clean away.