Yingyi Bu created ASTERIXDB-1500:
------------------------------------
Summary: Inject filters to eliminate null/missing join keys for
equality joins
Key: ASTERIXDB-1500
URL: https://issues.apache.org/jira/browse/ASTERIXDB-1500
Project: Apache AsterixDB
Issue Type: Improvement
Components: Optimizer
Reporter: Yingyi Bu
Assignee: Yingyi Bu
For the following query, there could be many tweets that has the field
in_reply_to_status_id being null/missing. Therefore, that would skewness of for
the hash join. Since this is an inner join and missing/null join keys anyway
could not produce qualified join results, the optimizer should inject
null/missing filters before the join.
{noformat}
FROM Tweets t2 JOIN Tweets t1 ON t2.in_reply_to_status_id = t1.id
WHERE not(`is-unknown`(t2.in_reply_to_status_id))
GROUP BY t1.id AS id, t1.user.name AS name, t1.text AS text
SELECT id, name, text, COUNT(t2) AS num_retweets
ORDER BY num_retweets DESC
LIMIT 5;
{noformat}
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
