Redshift terminates long running query

3
votes

I have observed that redshift terminate long running queries. We have a query which runs about 16min 30 sec(fired from python application) after which this query is terminated at RedShift end. Is there a way I can track why this query got terminated?

To check reason I executed this query from psql cli. After query is terminated at server end seems line psql cli didn't received any response from RedShift. So cli client was waiting for a long time even after query is terminated. Any ideas for this behavior.

1
pythonamazon-redshiftpsql

1 Answers

0
votes

This sounds like the description to a problem I've encountered myself some time ago when executing queries originating from EC2 instances. Queries appeared to be completed on the cluster but the client never received a result. The error disappeared when I set a LIMIT 1 at the end of the query. Maybe use this to verify that you indeed do have the same issue.

Setting the MTU to 1500 solved the problem for me. On Linux:

$ sudo ip link set dev eth0 mtu 1500

Redshift has a thorough description and solutions in its documentation: http://docs.aws.amazon.com/redshift/latest/mgmt/connecting-drop-issues.html