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Getting a timeout on lock

  • April 21, 2016
  • 2 replies
  • 13 views
Luc_Lecocq
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Hello,

 

I am having a problem when trying to do an alter table.

I am consistently getting the same error:

Internal error (system details [Vertica][VJDBC](5157) ERROR: Unavailable: [Txn 0xb00000000000d6] O lock table - timeout error Timed out O locking Table:public.TABLE_NAME. T held by [user <unknown> (Mergeout: (Table: public.TABLE_NAME) (Projection: public.TABLE_NAME_PERFORMANCE_2_b1_v1_0))]. Your current transaction isolation level is SERIALIZABLE)

 

Does this mean that a mergeout is in progress on that table ?

If yes, this does not make sense, because when running "

SELECT node_name, operation_status, projection_name, plan_type FROM TUPLE_MOVER_OPERATIONS;"

does not report ANY mergeout running on this table.

 

What can I do to proceed with my changes ?

 

Thanks for helping

    2 replies

    Gayatri_R
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    • Gayatri_R
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    • April 21, 2016

    Hi

    Are you querying tuple_mover_operations as dbadmin? It should have a running mergeout task on the table in question. If not, please see if you can identify the session id from vertica.log and use close_session to end it. After closing the session holding the lock, the ALTER TABLE DDL will go through.

    Thanks

    Gayatri

    Luc_Lecocq
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    • Luc_Lecocq
    • Author
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    • April 22, 2016

    Hi,

     

    Thanks for your answer,

    We have finally identified the reason for the mergeout lock, it was caused by an UPDATE that was inside our SQL script. Since we were looking for locks before running the script, we did not see anything.

    We just temporarily disabled the mergeout service, and the script was able to run.

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