On Jan 31, 2014, at 3:43 PM, Jens Alfke <j...@couchbase.com> wrote: > On Jan 31, 2014, at 12:07 PM, Boaz Citrin <bcit...@gmail.com> wrote: > >> But if replication only copies the leaf then it makes sense that it is >> fatser, at least on the same machine. Instead of balancing a tree it just >> copies a single revision. > > Um, no. The copied revision has to be inserted into the tree on the target > database. Worse, the target database is assumed to be 'live' during the whole > process, so its tree can't be updated as efficiently as during a replication, > where the new database file isn't going to be used at all until the whole > procedure finishes. > > Sorry to pull rank, but while I haven't worked on CouchDB itself, I've > written 1½ CouchDB-compatible replicators, and I've worked on a C-based > compactor for CouchDB-format b-tree files. I'm pretty sure that compaction is > a lot faster. There's just much less work that it has to do. > > I agree with Jason that you probably need a faster server (or disk) that will > let you compact effectively. > > —Jens
Agreed, and also worth pointing out that we've developed a compactor that is far more efficient than the one in master. It uses less I/O and generates a smaller file to boot: https://git-wip-us.apache.org/repos/asf?p=couchdb-couch.git;a=commit;h=5d3753d0662cfa676fdf65d0a543be205499ec11 Hopefully we can land it soon. Regards, Adam
