Hi,
I think we might be able to reuse, Schema discovery features of
http://metamodel.incubator.apache.org/
Although its seems incubator, but at
http://metamodel.eobjects.org/goals.html it was pretty mature
(version-ed till 3.4)
One of the most distinguising feature is "Traversing and building
the *structure* of datastores"; which matches with our goal of "Late
schema" support.
-Dhruv
On 11/02/2013 11:21 AM, Timothy Chen wrote:
Hi Julian,
Glad to have someone responded to this :) Yes I think going beyond just
having no schema defined up front to actually giving users possibilities is
definitely a much better interactive experience.
I would imagine though that it could impact Drill, or perhaps build more
statistics capabilities in Drill to query schema info, since not all data
is just raw files but could be living in different data stores, then I
would think we need to talk through the Drill storage engine abstraction to
get those info.
I'll chat about this with Jacques and folks next monday or in the Drill
user group.
Tim
On Fri, Nov 1, 2013 at 4:51 PM, Julian Hyde <[email protected]> wrote:
A recent blog post by Daniel Abadi has a similar theme:
http://hadapt.com/blog/2013/10/28/all-sql-on-hadoop-solutions-are-missing-the-point-of-hadoop/
We could create a tool that scans the raw files and generates an Optiq
schema that contains views that apply "late schema" (the "EMP" and "DEPT"
views in
https://raw.github.com/apache/incubator-drill/HEAD/sqlparser/src/test/resources/test-models.jsonare
examples of this). The user could interactively modify that schema
(e.g. change a column's type from string to boolean or integer).
It's a nice approach because it doesn't impact the Drill engine. This is
good. Metadata and data should be kept separate wherever possible.
Julian
