Getting a timeout on lock

Luc_Lecocq

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

Gayatri_R

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

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.