Execution canceled by operator Error

Abhishek_2

Hello,   
          I see many errors with "Execution canceled by operator " and "Node Failure in %s", i looked up in vertica Error Description it says it is class 57 Error, can you please help me understand what this actually means, what causes this and is this something we should worry about?

i use Vertica 5.X

Thanks,
Abhishek 

Abhishek_Rana

Hi,

We have seen such errors in logs & most of the times those are related to client application cancelling already running query transaction. If you are connecting to vertica from a client, most of the times it can be caused by the same client session executing another query in between , where a large resultset has not been completely fetched in one go for previously running query.
 
  The large result set is based on size vs. # of rows. The default buffer is 16k, so if your 200 records returned happen to be from a wide table with lots of columns you could still hit it. 
 
 Eg:
  There are some cases where the odbc driver will invoke SqlCancel(). For example, if a query that is returning a large result set has not fetched the complete result set. Invoking SqlClose() or executing another statement will result in the currently-executing statement being cancelled. Same can happen with a JDBC client application transaction to fetch records.
 
  Tweaking with your buffer result set settings at client side, you might get rid of this situation.

Regards'
Abhishek

Abhishek_2

thanks a lot for clearing the mist

can this ("Execution canceled by operator") happen if there is memory pressure, if so what buffer/memory setting should be looked at to mitigate this?


Regards,
Abhishek

Bhawana

Hi,

Also  do you see Resource Reservation Failure message in the log. You can check check the  resource rejection table to check if it due to unavailability of resources.

Regards

Bhawana