[jira] [Commented] (CALCITE-724) Add support for hash join using an index

["Julian Hyde (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-724?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14542515#comment-14542515 ] 

Julian Hyde commented on CALCITE-724:
-------------------------------------

Is it correct to call this a hash join? I get the idea that you take one row from the left and then use it to lookup rows on the right.

The distinction is important. With a hash join the "key" you get from the left would have to be a single value. If the data structure on the right is, say, a b-tree, then you the condition could be a single value, but it could also be a range, or even a collection of ranges, say "x is null or x between 100 and 200 or x = 500 or x > 1000". If we allow a fairly general expression then we will be able to fully exploit whatever search capabilities the index has.

We used to have support for "sargs" in Calcite but I obsoleted them. See https://github.com/apache/incubator-calcite/tree/8e480759fc25d7a1e10f7f20f9eddc7556beded8/core/src/main/java/org/eigenbase/sarg. We could revive them.

> Add support for hash join using an index
> ----------------------------------------
>
>                 Key: CALCITE-724
>                 URL: https://issues.apache.org/jira/browse/CALCITE-724
>             Project: Calcite
>          Issue Type: Improvement
>    Affects Versions: 1.3.0-incubating
>            Reporter: Andy Grove
>            Assignee: Julian Hyde
>
> I would like to implement a hash join where the left input is a stream or a table scan and for each incoming tuple I would like Calcite to perform an index-based lookup against a table to find matching tuples. 



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