Hello, Elastic announced <https://www.elastic.co/guide/en/elasticsearch/reference/master/removal-of-types.html> that they will be deprecating mapping types in ES6 and indexes will be single-typed only.
Historical analogy <https://www.elastic.co/blog/index-vs-type> between RDBMS and elastic was that index is equivalent to a database and type corresponds to table in that database. In a couple of releases (ES6-8) this shall not longer be true. Recent SQL addition <https://www.elastic.co/blog/elasticsearch-6-3-0-released> to elastic confirms this trend <https://www.elastic.co/guide/en/elasticsearch/reference/current/_mapping_concepts_across_sql_and_elasticsearch.html>. Index is equivalent to a table and there are no more ES types. I would like to propose to include this logic in Calcite ES adapter. IE, expose each ES single-typed index as a separate table inside calcite schema. This is in contrast to current integration where schema can only have a single index. Current approach forces you to create multiple schemas to query single-typed indexes (on the same ES cluster). Legacy compatibility can always be controlled with configuration parameters. Do you agree with such changes ? If yes, would you consider a PR ? Regards, Andrei.
