[jira] [Assigned] (HIVE-15267) Make query length calculation logic more accurate in TxnUtils.needNewQuery()

["Eugene Koifman (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-15267?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Eugene Koifman reassigned HIVE-15267:
-------------------------------------

    Assignee: Steve Yeom  (was: Wei Zheng)

> Make query length calculation logic more accurate in TxnUtils.needNewQuery()
> ----------------------------------------------------------------------------
>
>                 Key: HIVE-15267
>                 URL: https://issues.apache.org/jira/browse/HIVE-15267
>             Project: Hive
>          Issue Type: Bug
>          Components: Hive, Transactions
>    Affects Versions: 1.2.1, 2.1.0
>            Reporter: Wei Zheng
>            Assignee: Steve Yeom
>
> In HIVE-15181 there's such review comment, for which this ticket will handle
> {code}
> in TxnUtils.needNewQuery() "sizeInBytes / 1024 > queryMemoryLimit" doesn't do the right thing.
> If the user sets METASTORE_DIRECT_SQL_MAX_QUERY_LENGTH to 1K, they most likely want each SQL string to be at most 1K.
> But if sizeInBytes=2047, this still returns false.
> It should include length of "suffix" in computation of sizeInBytes
> Along the same lines: the check for max query length is done after each batch is already added to the query. Suppose there are 1000 9-digit txn IDs in each IN(...). That's, conservatively, 18KB of text. So the length of each query is increasing in 18KB chunks. 
> I think the check for query length should be done for each item in IN clause.
> If some DB has a limit on query length of X, then any query > X will fail. So I think this must ensure not to produce any queries > X, even by 1 char.
> For example, case 3.1 of the UT generates a query of almost 4000 characters - this is clearly > 1KB.
> {code}



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