On Thu, Sep 27, 2012 at 7:58 PM, Platonides platonides@gmail.com wrote:
On 27/09/12 01:07, Ryan Lane wrote:
We currently have no plans for having the user databases on the same servers as the replicated databases. Direct joins will not be possible, so tools will need to be modified.
-50
It's such a useful feature, that it would be worth making a local mysql slaves for having them. I know, the all-powerful labs environment is unable to run a mysql instance, but we could use MySQL cluster, trading memory (available) to get joins (denied).
I'm not the one setting up the databases. If you want information about why this won't be available, talk to Asher (binasher in #wikimedia-operations on Freenode). Maybe he can be convinced otherwise.
Of course, in the production cluster we don't do joins this way. We handle the joins in the app logic, which is a more appropriate way of doing this.
I disagree. In production you can just create a new table in the wiki db. We can't create new tables there in the toolserver (the dbs are a mirror or what there is in production). Thus, we create a new db in the same server and use a cross-db join instead of joining a new table.
Joining several wiki tables is probably more strange, with the exception of commons, which is more often joined to others, as the commons images "are also at the local wikis".
Which brings us to the next point, will the commons database be replicated to all clusters, like the toolserver?
Bryan