Do you eventually delete every document you add? If so, consider using a rolling database scheme instead. At some point, perhaps daily, start a new database and write new transaction logs there. Continue deleting old logs from the previous database(s) until they're empty (doc_count:0) and then delete the database.
B. On 14 June 2012 13:44, Nicolas Peeters <[email protected]> wrote: > I'd like some advice from the community regarding compaction. > > *Scenario:* > > We have a large-ish CouchDB database that is being used for transactional > logs (very write heavy). Once in a while, we delete some of the records in > large batches and we have scheduled compaction (not automatic (yet)) every > 12hours. > > From what I can see, the DB is being hammered significantly every 12 hours > and the compaction is taking 4 hours (with a size of 50-100GB of log data). > > *The problem:* > > The problem is that compaction takes a very long time and reduces the > performance of the stack. It seems that it's hard for the compaction > process to "keep up" with the insertions, hence why it takes so long. Also, > what I'm not sure is how "incremental" the compaction is... > > 1. In this case, would it make sense to run the compaction more often > (every 10 minutes); since we're write-heavy. > 1. Should we just run more often? (so hopefully it doesn't do > unnecessary work too often). Actually, in our case, we should probably > never have automatic compaction if there has been no "termination". > 2. Or actually only once in a while? (bigger batch, but less > "useless" overhead) > 3. Or should we just wait that a given size (which is the problem > really) is hit and use the auto compaction (in CouchDB 1.2.0) for this? > 2. In CouchDB 1.2.0 there's a new feature: auto > compaction<http://wiki.apache.org/couchdb/Compaction#Automatic_Compaction> > which > may be useful for us. There's the "strict_window" feature to give a max > amount of time to compact and cancel the compaction after that (in order > not to have it running for 4h+…). I'm wondering what the impact of that is > on the long run. What if the compaction cannot be completed in that window? > > Thanks a lot! > > Nicolas
