Thanks, Robert. Disabling delayed commits did make the problem start later, but it is still there.
It's funny that the first think that I checked when I first saw this problem was to make sure that delayed commits where enabled. Thanks, Marco On 11 May 2012 13:20, Robert Newson <[email protected]> wrote: > The first thing is to ensure you have disabled delayed commits; > > curl -XPUT -d '"false" localhost:5984/_config/couchdb/delayed_commits > > This is the production setting anyway (though not the default because > of complaints from incompetent benchmarkers). This will ensure an > fsync for each write and, as a consequence, will greatly smooth your > insert performance. Since you said you were inserting concurrently, > you should not experience a slowdown either. > > B. > > On 11 May 2012 02:42, Marco Monteiro <[email protected]> wrote: > > Hello! > > > > I'm running a load test on CouchDB. I have a cluster of 8 node.js servers > > writing to > > CouchDB. They write about 30000 documents per minute (500 per second). > > There are > > multiple concurrent requests form each server. There are no updates: > > documents are > > created and not modified. > > > > I first tried CouchDB 1.1.1 from Debian 6.4 apt repo. After a few > minutes, > > CouchDB > > starts freezing for a period of 1 to 3 seconds about every 10 seconds. It > > keeps this > > behaviour for some time and eventually it starts freezing more frequently > > and for longer > > periods. When the database has about 1.5 million documents, couchdb is > > freezing for > > more than 5 seconds each time. > > > > I then tried CouchDB 1.2, from build-couch. The freezes happen with it > > also, but the > > behavior is much worse: in less than one minute it's freezing for 5 > seconds > > or more, > > and it spends more time not doing anything than working. > > > > When testing with 1.1.1 I was writing only to one database. With 1.2 I > > tried with one database > > and then with multiple databases but the problem was exactly the same. > > > > The documents have about 10 properties, only numbers or string and the > > strings are small > > (about 20 chars each). The document IDs are generated in the app and have > > the format > > > > <milliseconds since epoch>-<random 16 chars string> > > > > When CouchDB freezes, it's processor use (from top) goes to zero. It does > > not reply to read or write > > requests. The disk does not seem to be the problem as iostat reports > near > > 0% utilization. > > CPU is mostly idle, and from the 16 GB of RAM, some of it is free and is > > not even used to > > cache disk. > > > > There are no error message in Couchdb log. > > > > I tried this in two different machines and the problem is the same in > both. > > > > I did not change anything in the configuration files expect changing the > > database dir to use > > a RAID partition. > > > > Anyone has any idea of what the problem could be? > > > > Any help solving this issue is greatly appreciated. > > > > Thanks, > > Marco >
