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.
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
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
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".