On 12 June 2015 at 14:13, Chetan Mehrotra <[email protected]> wrote:
> On Fri, Jun 12, 2015 at 5:20 PM, Ian Boston <[email protected]> wrote: > > Are all queries expected to query all keys within a collection as it is > > now, or is there some logical structure to the querying ? > > Not sure if I get your question. The queries are always for immediate > children. For for 1:/a the query is like > > $query: { _id: { $gt: "2:/a/", $lt: "2:/a0" } > So, knowing that /a and all its children was in collection nodes_a, you would only need to query nodes_a ? But if /a was stored in nodes_root and its children were stored in nodes_[a-z] (26 collections), then you would need to map reduce over all 26 collections ? Initially I was thinking about the locking behaviour but I realises 2.6.* is still locking at a database level, and that only changes to at a collection level 3.0 with MMAPv1 and row if you switch to WiredTiger [1]. Even so, would increasing the number of collections have an impact on query costs. ie put /oak:index in its own collection and isolate its indexes ? Best Regards Ian 1 http://www.wiredtiger.com/ > > Chetan Mehrotra >
