> On 30 Nov 2016, at 15:34, Alan Kash <[email protected]> wrote: > > Thanks Jan. > > I am not sure whether this is in the feature pipeline.
Not sure what you mean? > > Another related query, *Live/Push queries* on views, the idea is to have a > pub/sub kind of model, where clients subscribe to queries / views. We have _changes on databases, and you can use view map functions (and Mango queries) as filters. This isn’t 100% what you want, but it get get you half way there. There has been some preliminary work on offering proper _changes on views as well, but conceptually, this is still a bit half-baked. I’m sure we’ll get there eventually. Best Jan -- > > > > On Wed, Nov 30, 2016 at 4:53 AM, Jan Lehnardt <[email protected]> wrote: > >> >>> On 30 Nov 2016, at 00:06, Alan Kash <[email protected]> wrote: >>> >>> Yes, from the link it mentions about stale views. >>> >>> Will be interested to know the merits of db pool vs view pool first >> model. >>> Logically, the queries are coming from top, and the view updates are >>> propagated bottom up. >> >> The internal data structure benefits from bulk inserts vs single inserts. >> >> I.e. it takes (accumulated) less CPU, RAM, Disk, to update the view index >> with 10 docs in one bulk operation instead of 10 individual operations. >> >>> On a similar note, do the view updates leverage >>> parallel processing in multicore systems. >> >> In CouchDB 1.x: no, this is single threaded, albeit spread over two >> operating system processes, but using a blocking protocol, so together, >> they wouldn’t exhaust a single CPU. >> >> In CouchDB 2.x, if you set up multiple shards per cluster node, you >> basically get a CPU per shard for view computation, effectively using >> multicore systems optimally. >> >> Best >> Jan >> -- >> >> >>> >>> >>> >>> On Tue, Nov 29, 2016 at 5:49 PM, Robert Keizer <[email protected]> wrote: >>> >>>> After a document is added. >>>> >>>> My understanding is that the insertion to the main document pool happens >>>> at the start, with views being triggered to update after the document >>>> exists in that index. >>>> >>>> Someone with more experience may correct me - but I'm fairly certain >>>> this is why views can be stale ( >>>> http://docs.couchdb.org/en/2.0.0/api/ddoc/views.html ) >>>> >>>> >>>> On 2016-11-29 4:47 PM, Alan Kash wrote: >>>>> Hello, >>>>> >>>>> CouchDB starter here. >>>>> >>>>> How are the MapReduce views updated ? Before or after a new document is >>>>> added into store ? >>>>> >>>>> Do all document insertions go through some view process pipeline, then >>>>> finally to base document pool ? I am thinking in document stream >>>>> processing terms, where document ingress hits the *views processes* >> first >>>>> before finally ending up in the pool. >>>>> >>>>> Thanks >>>>> >>>> >>>> >>>> >> >> -- >> Professional Support for Apache CouchDB: >> https://neighbourhood.ie/couchdb-support/ >> >> -- Professional Support for Apache CouchDB: https://neighbourhood.ie/couchdb-support/
