[ https://issues.apache.org/jira/browse/ASTERIXDB-1500?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Yingyi Bu reassigned ASTERIXDB-1500: ------------------------------------ Assignee: Dmitry Lychagin (was: Yingyi Bu) > 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: COMP - Compiler > Reporter: Yingyi Bu > Assignee: Dmitry Lychagin > Labels: soon > > 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 (v6.4.14#64029)