[jira] [Resolved] (IMPALA-8606) GET_TABLES performance in local catalog mode

["Quanlong Huang (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IMPALA-8606?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Quanlong Huang resolved IMPALA-8606.
------------------------------------
    Resolution: Fixed

> GET_TABLES performance in local catalog mode
> --------------------------------------------
>
>                 Key: IMPALA-8606
>                 URL: https://issues.apache.org/jira/browse/IMPALA-8606
>             Project: IMPALA
>          Issue Type: Bug
>          Components: Catalog
>    Affects Versions: Impala 3.2.0
>            Reporter: Balazs Jeszenszky
>            Assignee: Quanlong Huang
>            Priority: Blocker
>              Labels: catalog-v2
>
> With local catalog mode enabled, GET_TABLES JDBC requests will return more than the always available table information. Any request for more metadata about a table will trigger a full load of that table on the catalogd side, meaning that GET_TABLES triggers the load of the entire catalog. Also, as far as I can see, the requests for more metadata are made one table at a time. 
> Once the tables are loaded on the catalogd-side, a coordinator needs 3 roundtrips to the catalog to fetch all the details about a single table. My test case had around 57k tables, 1700 DBs, and ~120k partitions. 
> GET_TABLES on a cold catalog takes 18 minutes. With a warm catalog, but cold impalad, it still takes ~70 seconds.
> Many tools use GET_TABLES to populate dropdowns, etc. so this is bad for both end user experience and catalog memory usage.



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