[jira] [Commented] (FLINK-5752) Support push down projections for HBaseTableSource

["ramkrishna.s.vasudevan (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-5752?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15859357#comment-15859357 ] 

ramkrishna.s.vasudevan commented on FLINK-5752:
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Since FLINK-5698 is in progress I thnk my way of trying to do the push down without nested schema is not needed. Once FLINK-5698 is done and https://github.com/apache/flink/pull/3149 is also committed we can make this change in HbaseTableSource.

> Support push down projections for HBaseTableSource
> --------------------------------------------------
>
>                 Key: FLINK-5752
>                 URL: https://issues.apache.org/jira/browse/FLINK-5752
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Table API & SQL
>            Reporter: ramkrishna.s.vasudevan
>            Assignee: ramkrishna.s.vasudevan
>
> This is after the discussion to create NestedProjectableTableSource. 
> Currently we support nested schema for the non-relational type of DBs like HBase. 
> But this does not allow push down projection. This JIRA is to implement that. 
> I just did a POC on the existing PR https://github.com/apache/flink/pull/3149.
> The idea was to allow the family#quallifier to be specified in the query directly and parse the family and qualifier info and directly push down for projections.
> I tried using fam$qual (with $) as separator but that had SQL parse error. Hence went with '_' as the separator and it worked. 
> So now in order to maintain the order in which the projection has to be done we need to have a LinkedHashMap which has the qualifier to typeinfo mapping. This is because with f1_q1, f1_q2 as the schema, we could always project f1_q2 and the selection could be f1_q1. In that case the order of how the projection is done is very important so that there is no type mismatch. 
> [~fhueske], [~tonycox], [~jark]



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