OK, I've added the replies from Robert and Paul to http://wiki.apache.org/couchdb/FUQ
Then it is right to say that there are informations that can't be deleted from a database, for example the _id of documents? Thanks for the clarifications, since this behaviour was totally non obvious to me. Marcello 2011/12/23 Robert Newson <[email protected]>: > An update to the wiki would be be very helpful. > > It's worth saying again that compaction does *not* remove "deleted > documents’ contents". We keep the latest revision of every document > ever seen, even if that revision has _deleted:true in it. This is so > that replication can ensure eventual consistency between replicas. Not > only will all replicas agree on which documents are present and which > are not, but also the contents of both. > > B. > > On 23 December 2011 08:11, Marcello Nuccio <[email protected]> wrote: >> 2011/12/23 Paul Davis <[email protected]>: >>> On Thu, Dec 22, 2011 at 7:00 PM, Jens Alfke <[email protected]> wrote: >>>> >>>> On Dec 22, 2011, at 1:44 PM, Chris Stockton wrote: >>>> >>>> Okay, so this catches me a bit off guard, always thought compaction >>>> cleaned those up. >>>> >>>> Compaction removes old revisions’ and deleted documents’ contents, but >>>> their revision histories are still there. Those should be pretty small, >>>> though, since they’re just trees of revision IDs. >>>> >>>> (Unless you did delete the docs by just setting a “_deleted” attribute? I >>>> don’t know what the behavior of that would be; sounds like it doesn’t >>>> actually delete the document from the database, in which case maybe the >>>> last revision data does get left behind.) >>>> >>>> —Jens >>> >>> Deleted documents specifically allow for a body to be set in the >>> deleted revision. The intention for this is to have a "who deleted >>> this" type of meta data for the doc. Some client libraries delete docs >>> by grabbing the current object blob, adding a '"_deleted": true' >>> member, and then sending it back which inadvertently (in most cases) >>> keeps the last doc body around after compaction. >> >> Can I write these informations in the wiki? >> I think it would be very useful in >> http://wiki.apache.org/couchdb/Compaction >> and in http://wiki.apache.org/couchdb/FUQ >> >> Marcello
