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Re: ElasticSearch. Explicit Definitions, Literals and RelBuilder


1) I'm not too familiar with ES so I didn't realize you could define
mappings. I don't see any obvious reason why we couldn't use those assuming
they're exposed via the ES API.

2) I was not aware of this and not sure whether it was intentional. It
seems like a bug to me though.

3) Whenever you want to see how to build a particular query, you may find
it helpful to run "EXPLAIN PLAN FOR <query>" in sqlline.

--
Michael Mior
mmior@xxxxxxxxxxxx


Le jeu. 17 mai 2018 à 01:26, Andrei Sereda <andrei@xxxxxxxxx> a écrit :

> Hello Calcite Devs,
>
> I have some questions about ES adapter and custom predicates / projections
> in Calcite. Your help is much appreciated.
>
> 1) All ES examples use a view (ZIPS
> <
> https://github.com/apache/calcite/blob/master/elasticsearch5/src/test/resources/elasticsearch-zips-model.json
> >)
> which does explicit type cast, name alias and  dictionary access (via _MAP)
> for each field. If such view is not defined beforehand, making ad-hoc
> queries becomes tedious. Is there a way to make it more user-friendly (eg.
> using existing ES mapping) ?
>
> Example: select cast(_MAP['city'] AS varchar(20)) AS \"city\" from ...
>
> Why some adapters require explicit definition (eg. Mongo / ES) while others
> don't (eg. Geode)
>
> 2) When not using explicit casting (or field alias) query literals are
> converted to lower case:
>
> SQL: select * from "elastic" where _MAP['Foo'] = 'BAR' (note upper-case)
> ES Query: { "term": { "foo" : "bar" }} (note lower-case)
>
> This is less intuitive. Is there a way to switch it off (customize) ?
>
> 3) How to build the following query using Algebra Builder (RelBuilder)
>
> select * from "elastic" where _MAP['Foo'] = 'Bar'
>
> I presume one has to use SqlItemOperator but I couldn't get it to work. Is
> this related to (1) and (2) ?
>
> Regards,
> Andrei.
>