[jira] [Commented] (HIVE-13531) Cache in json_tuple UDF grows larger than it should

["Gopal V (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-13531?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15244443#comment-15244443 ] 

Gopal V commented on HIVE-13531:
--------------------------------

The concurrent access might be due to local fetch-task conversions.

{{set hive.fetch.task.conversion=none;}}

> Cache in json_tuple UDF grows larger than it should
> ---------------------------------------------------
>
>                 Key: HIVE-13531
>                 URL: https://issues.apache.org/jira/browse/HIVE-13531
>             Project: Hive
>          Issue Type: Bug
>          Components: UDF
>    Affects Versions: 1.1.0
>         Environment: CDH 5.5.0 with Java 1.8.0_45
>            Reporter: Jürgen Thomann
>            Assignee: Jason Dere
>            Priority: Minor
>
> According to the code in ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDTFJSONTuple.java the HashCache should never grow larger than 16 entries. In the last OOM of Hive Server 2 I found this HashCache with over 1 million java.util.LinkedHashMap$Entry objects.
> The code looks right and works single threaded as it should when I tested it isolated. The only problem I can imagine with my limited Hive source code knowledge that it is accessed concurrently and somewhere the cleanup with removeEldestEntry is not working in that case.
> I had this problem with Hive 1.1.0 but the current implementation in master looks the same for the HashCache.



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