On Thu, Dec 13, 2012 at 5:46 PM, Robert Newson <[email protected]> wrote:
> Views are also sharded. > > It's common for a node to host multiple shards of the same database, > so we already have this 'concurrent writes' notion, if I've > interpreted it correctly. > > Well my question are more related why using a mapping ? And how to keep the backup of one database easy for a user. Possibly without relying on a mapping stored aside. Other question is why bigcouch choose that design vs the one I propose. @Hans since db are shared and views are done / db ,views indexations are also concurrent. - benoît > On 13 December 2012 16:36, Hans J Schroeder <[email protected]> wrote: > > > > On Dec 13, 2012, at 5:06 PM, Benoit Chesneau <[email protected]> > wrote: > > > >> Hi all, > >> > >> > >> This morning I was back reading a lot of fundamentals about databases > and > >> such and was asking myself how we could increase the number of > concurrent > >> writes. > >> > >> These days the theory is that it will be solved by sharding the > databases > >> in multiples database files and merging results of the queries. Since > the > >> databases will be shareded then the writes on the same db will be > >> concurrents. A map of the shards willl be kept aside. All of this > thanks to > >> the introduction of bigcouch. > >> > >> The question I have is why don't we already do that? Ie balancing datas > on > >> different files on one db? for example the db folder could be > >> > >> database/XY.couch > >> > >> where XY are the first letters of an id or content hash or any > consistent > >> hashing method. > >> > >> I am currently asking myself such question because I am wondering how > will > >> the backup works when couchdb will be used as a single node. How to > backup > >> only one db without having to query for the mapping and such? How to > keep > >> it it simple. > >> > >> Related to that why did bigcouch used that design? Why mapping shards > in a > >> db database instead of having some kind of natural balancing on the fs > and > >> having a consistent hashing algorithm used to balance on different > >> machines/vms as well ? > >> > >> > >> - benoît > > > > > > Hi, > > > > That's like "horizontal partitioning" in conventional databases and I > think its a great idea. Having a writer process for each partition will > make it scale. > > > > Does Bigcouch have anything for the view files too or are they just > sharding the backing files? > > > > - Hans >
