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From Adam Kocoloski <>
Subject Re: Cloudant Query
Date Fri, 27 Jun 2014 23:52:39 GMT
On Jun 27, 2014, at 6:35 PM, Alexander Shorin <> wrote:

> On Sat, Jun 28, 2014 at 1:55 AM, Adam Kocoloski <> wrote:
>> On Jun 27, 2014, at 5:07 PM, Alexander Shorin <> 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,

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