I don't think end users need a list of dbs they can access on the server. Think the simplest answer is to only support _all_dbs operation for admins and be done.
-Damien On Mar 1, 2010, at 1:40 AM, Brian Candler wrote: > On Mon, Mar 01, 2010 at 09:55:46AM +0100, Filipe David Manana wrote: >>> The reason for no storing _security as a doc is an optimization. So we >>> extend that optimization, and have something like a security_changed event >>> for a db, that the _dbs database can react to. The model isn't different >>> from subscribing to _changes, it'd just be a separate code path. >> >> That's a good idea (both simple and more efficient). >> >> The only issues left are the cases where the user adds a new DB file >> (possibly coming from other server for e.g.) into the DB dir, deletes a DB >> file or replaces a DB file with an old version (a backup whose update seq >> number is from the past). > ... >> Do you think this would add too much overhead or it could be a somewhat >> "light" approach? Or better, do you have a better idea for it? > > Just as an idea, you could just turn this on its head. Suppose _dbs was the > primary source of information; then the _security record within the database > is just a cached copy of that. It's easy enough to take a _changes feed > from _dbs to update this cache. > > But in that case, the cache would be better kept in RAM, rather than within > the database file. > > After all, CouchDB already keeps a cache of open database filehandles, > doesn't it? So you could read the security information from a regular > document (an "expensive" operation) when you open the database, and then > just continue to use that version thereafter. You'd invalidate the cache if > the corresponding _dbs object is updated. > > However this leaves the following issue: what if the database file is > renamed on disk, or disk-copied to a different system which happens to have > an existing _dbs entry for that name? > > I think the best solution is for the _dbs database to be indexed by uuid. > But to make this work efficiently, the database file *on disk* should also > be named by its uuid, rather than the database name. That's probably too > big a change to swallow at this stage. > > But it does have some other side benefits (such as being able to "rename" a > database instantly without touching the filesystem, and being able to > automatically spread a large number of databases across directories without > forcing the user to use database names like 00/xxx, 01/yyy, 02/zzz etc) > > Regards, > > Brian.
