[jira] [Assigned] (ASTERIXDB-3470) CBO estimates incorrect join cardinality with IMDb datasets

["Ian Maxon (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ASTERIXDB-3470?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Ian Maxon reassigned ASTERIXDB-3470:
------------------------------------

    Assignee: Vijay Sarathy

> CBO estimates incorrect join cardinality with IMDb datasets
> -----------------------------------------------------------
>
>                 Key: ASTERIXDB-3470
>                 URL: https://issues.apache.org/jira/browse/ASTERIXDB-3470
>             Project: Apache AsterixDB
>          Issue Type: Bug
>          Components: COMP - Compiler
>            Reporter: Mehnaz Tabassum Mahin
>            Assignee: Vijay Sarathy
>            Priority: Major
>              Labels: triaged
>         Attachments: join_queries.txt, load_and_analyze.txt, schema.txt
>
>
> The join cardinalities with IMDb datasets are *much overestimated* and the inaccuracy increases with the increase in sample sizes.
> IMDb dataset: [http://homepages.cwi.nl/~boncz/job/imdb.tgz  |http://homepages.cwi.nl/~boncz/job/imdb.tgz](Please change the corresponding CSV file name to "keywords.csv")
> In the attachment, two 10-datasets join queries and the relevant DDL statements are given. Both join queries are with 10 IMDb datasets and different selectivity predicates.
>  # The actual cardinality of the first join query is {*}1298{*}, where the estimated ones are:
>  ** with "low" sample: 7.489 x 10{^}10{^}
>  ** with "medium" sample: 5.619 x 10{^}12{^}
>  ** with "high" sample: 6.022 x 10{^}12{^}
>  # The actual cardinality of the second one is {*}1062{*}, whereas the estimated ones are:
>  ** with "low" sample: 4.33 x 10{^}8{^}
>  ** with "medium" sample: 1.479 x 10{^}11{^}
>  ** with "high" sample: 1.93 x 10{^}11{^}



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