Xapian discuss - Aug 2012 - multiple database search performance

Hello

I'm developing a search system for our file servers, and as a basic way 
to handle file permissions, I decided to split things up in multiple 
index databases. This seemed to be the easiest and cleanest way to do it.

I implemented it and always tested it with smaller indexes (smaller than 
1000 docs per index) and everything went fine and search performance 
over multiple databases was great.

But now I indexed a larger part of the filesystem in one index, which 
grew to over 6000 documents. Searching only this index is still fast as 
hell. But doing a combined search with only one other database makes 
searching a real pain. Most of the queries I tested took about 15 
seconds to finish, with some queries taking 30 seconds and even longer.
Of course I expected it to be a bit slower, but by just adding those 100 
docs from another database into the search, searching becomes way too 
slow to work with it.

I wonder if there's a way I can improve search performance over multiple 
databases? Has anyone dealt with this issue before? Or have I made a 
wrong architectural choice in the beginning?

Thanks in Advance,
Alain

This is not what I'd expect at all; searching across multiple
databases has a small overhead but shouldn't really be significantly
slower than searching the component databases.  Either you're doing
something wrong, or there's a bug.

Let's try and work out which.  For starters:

When you say you're searching across multiple databases, are you
searching across them locally, or using the remote database protocol?
What OS and version of Xapian are you using?

-- 
Richard