I'll update the docs. However, for now we have: --- When a database is created, deleted, or updated, a corresponding event will be persisted to disk (Note: This was designed without the guarantee that a DB event will be persisted or ever occur in the _db_updates feed. It probably will, but it isn't guaranteed). Users can subscribe to a _changes-like feed of these database events by querying the _db_updates endpoint.
When an admin user queries the /_db_updates endpoint, they will see the account name associated with the DB update as well as update --- And technically, the endpoint can work without the _global_changes database, but be aware: --- 3: global_changes, update_db: (true/false) A flag setting whether to update the global_changes database. If false, changes will be lost and there will be no performance impact of global_changes on the cluster. --- This is all from https://github.com/apache/couchdb-global-changes I also learned something new today! -Joan ----- Original Message ----- From: "Vladimir Kuznetsov" <vova...@gmail.com> To: "Joan Touzet" <woh...@apache.org> Cc: user@couchdb.apache.org Sent: Tuesday, 27 June, 2017 1:53:02 AM Subject: Re: _global_changes purpose Thanks Joan. Very good to know. It'd be great to have this reflected somewhere in the official couchdb 2.0 docs. Probably it is already there I just could not find that... thanks, --Vovan > On Jun 26, 2017, at 10:42 PM, Joan Touzet <woh...@apache.org> wrote: > > _db_updates is powered by the _global_changes database. > > -Joan > > ----- Original Message ----- > From: "Vladimir Kuznetsov" <vova...@gmail.com> > To: user@couchdb.apache.org, "Joan Touzet" <woh...@apache.org> > Sent: Tuesday, 27 June, 2017 12:39:55 AM > Subject: Re: _global_changes purpose > > Hi Joan > > I heard /_db_updates is the feed-like thing I could subscribe to listen to > the global updates(same way you described). It is not very clear why would I > need access to _global_changes database when I already have /_db_updates > method with pagination and long-polling features. > > Is listening on _global_changes's /_changes feed the same as listening on > /_db_updates? Or is there any difference? What is preferred? > > thanks, > --Vovan > > >> On Jun 26, 2017, at 9:21 PM, Joan Touzet <woh...@apache.org> wrote: >> >> Say you have 100 databases and you want to know when something changes on all >> of them. In 1.x you have to open 100 _changes continuous feeds to get that >> information. In 2.x you have to open a single connection to _global_changes. >> >> Think of the possibilities. >> >> -Joan >> >> ----- Original Message ----- >> From: "Vladimir Kuznetsov" <vova...@gmail.com> >> To: user@couchdb.apache.org >> Sent: Monday, 26 June, 2017 8:47:46 PM >> Subject: _global_changes purpose >> >> Hi guys >> >> I cannot find any good explanation what's the purpose of _global_changes >> system database in CouchDB 2.0. Can somebody please explain or provide some >> pointer? >> >> thanks >> --Vovan >
