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https://issues.apache.org/jira/browse/HIVE-18864?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sankar Hariappan reassigned HIVE-18864:
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> WriteId high water mark (HWM) is incorrect if ValidWriteIdList is obtained
> after allocating writeId by current transaction.
> ---------------------------------------------------------------------------------------------------------------------------
>
> Key: HIVE-18864
> URL: https://issues.apache.org/jira/browse/HIVE-18864
> Project: Hive
> Issue Type: Sub-task
> Components: Transactions
> Affects Versions: 3.0.0
> Reporter: Sankar Hariappan
> Assignee: Sankar Hariappan
> Priority: Blocker
> Labels: ACID
> Fix For: 3.0.0
>
>
> For multi-statement txns, it is possible that write on a table happens after
> a read. Let's see the below scenario.
> # Committed txn=9 writes on table T1 with writeId=5.
> # Open txn=10. ValidTxnList(open:null, txn_HWM=10),
> # Read table T1 from txn=10. ValidWriteIdList(open:null, write_HWM=5).
> # Open txn=11, writes on table T1 with writeid=6.
> # Read table T1 from txn=10. ValidWriteIdList(open:null, write_HWM=5).
> # Write table T1 from txn=10 with writeId=7.
> # Read table T1 from txn=10. {color:#d04437}*ValidWriteIdList(open:null,
> write_HWM=7)*. – This read will able to see rows added by txn=11 which is
> still open.{color}
> {color:#d04437}{color:#333333}So, it is needed to rebuild the open/aborted
> list of ValidWriteIdList based on txn_HWM. Any writeId allocated by txnId >
> txn_HWM should be marked as open.{color}
> {color}
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