Taewoo Kim created ASTERIXDB-1984:
-------------------------------------
Summary: Index-Nested-Loop Join should not care about the contents
of the probe branch
Key: ASTERIXDB-1984
URL: https://issues.apache.org/jira/browse/ASTERIXDB-1984
Project: Apache AsterixDB
Issue Type: Bug
Reporter: Taewoo Kim
Assignee: Taewoo Kim
Currently, when the optimizer tries to transform a query with the "index_nl"
hint, it tries to identify datasource, assign, and unnest operators in both
outer (probe) and inner branch. It also tries to identify the fieldname of the
variables that are being joined. However, the probe branch can be an arbitrary
sub-plan and what only really matters for the probe subtree is the type of the
field from the probe tree that is being joined. If that field type is correctly
identified, then any form of probe-subtree with a simple data-scan on the inner
branch can be correctly transformed into an index-utilization plan. The
following queries should be transformed into an index-utilization plan.
However, they are not transformed now in the current master.
E.g.,
{code}
SELECT * FROM
[1, 2, 3] AS bar JOIN foo on bar = /*+ indexnl */ foo.key;
SELECT * FROM
bar JOIN foo on bar.id = foo.key JOIN datac ON foo.key = /*+ indexnl */
datac.val;
SELECT * FROM
(SELECT id, COUNT(*) FROM bar GROUP BY id) AS barr JOIN foo ON barr.id= /*+
indexnl */ foo.key;
{code}
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