On Jun 27, 2014, at 6:35 PM, Alexander Shorin <[email protected]> wrote:

> On Sat, Jun 28, 2014 at 1:55 AM, Adam Kocoloski <[email protected]> wrote:
>> On Jun 27, 2014, at 5:07 PM, Alexander Shorin <[email protected]> wrote:
>> 
>>> Hi Adam and thanks for the answers. Few more questions about if you don't 
>>> mind:
>>> 
>>> 1. Since "The _index endpoint is mostly syntactic sugar and validation
>>> on top of _design documents." doesn't this violates REST API
>>> principles when each object must have since operational endpoint? Why
>>> the _index/_find doesn't follow common pattern as:
>>> /db/_design/ddoc/_index/foobarbaz ?
>> 
>> There may well be improvements to the _index API that would allow it to 
>> better conform to REST principles.
>> 
>> I'm not sure the same applies for _find. A significant part of the power of 
>> the _find operator is its ability to select from among various indexes on 
>> the DB in order to respond to a declarative query. Scoping _find to a design 
>> document doesn't make sense. One might argue about GET vs. POST in the API 
>> but we've seen time and again that taking a complex query and URL-encoding 
>> it makes for an unfriendly experience. We started that way with our Search 
>> offering and ultimately exposed a POST variant. Did you have something else 
>> in mind regarding REST and _find?
> 
> No, that's probably my lack of knowledge about how they works. I
> thought that _find and another sugar on top of index querying, but I
> feel now it's completely different thing.
> 
>>> 2. What were the reasons for taking MongoDB approach? I could see the
>>> one about share users market, but only.
>> 
>> You write about user market share like it's a bad thing :) Seriously though, 
>> there are certainly alternatives out there for writing declarative queries 
>> against JSON datastores, but we didn't feel strongly enough about the 
>> superiority of any of them to ignore all the developers who have recognized 
>> that MongoDB's query documents offer a pleasant and powerful way to interact 
>> with JSON(-ish) data.
> 
> Didn't wrote about user market as about something bad, but I'm glad
> that you asked about bad things (: There is a doubt for the case when
> users will expect _exactly_ the same behavior (even bugged) from
> Cloudant Query implementation as MongoDB does. This remind the SQL
> history, when major database players took the same specification, but
> during marketing war started develop their own deviations and now we
> have what we have - a lot of partially compatible deviations of the
> same specification. Won't the history repeat itself for Cloudant Query
> since the goal to share user market by sharing foreign solutions makes
> Cloudant heavily depended from MongoDB company policy about plans for
> their query syntax? You have to always play catch-up in cases of
> bringing significant improvements or making breaking compatible
> decisions.
> 
> That's why I had asked about alternative solutions, especially if they
> are proposed or aims to be a common standard.

So there's a few things going on here. If we had gone out and implemented the 
MongoDB wire protocol and said "hey everybody, bring your MongoDB apps and run 
them on Cloudant!" then we'd absolutely run into a situation where any 
deviations we had from the MongoDB implementation would be magnified, and we'd 
be perpetually working to stay in sync with our friends down in New York. But 
that's not what we've done here. We're still sporting an HTTP+JSON interface. 
The query language should look familiar to anyone who's developed against 
MongoDB, but byte-for-byte fidelity is not the goal.

Standardization is a complex topic. I kind of feel like you're arguing both 
ways in in that you're expressing a preference for query languages that aim to 
be a common standard, but then worrying about history repeating itself vis a 
vis SQL (which, last I checked, *is* a common standard). If your proposed 
standard takes off then you'll always run the risk of vendors releasing 
proprietary extensions to said standard. That said, I happen to believe that 
the standardization of SQL catalyzed a wave of adoption of RDBMS and was a 
great thing for the industry as a whole. It may be that we'll see a similar 
thing occur in document databases -- who knows? Cheers,

Adam

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