Sankar Hariappan created HIVE-18864: ---------------------------------------
Summary: 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 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} -- This message was sent by Atlassian JIRA (v7.6.3#76005)