HAWQ Queries Failing after NameNode Failover

Products

• Services Suite

Issue/Introduction

Symptoms:
Whenever Standby Namenode is acting as Active Namenode, you are not able to create HAWQ external tables. Once switched over to the Active Namenode, external tables can be created in HAWQ.

Environment

Cause

The following HAWQ filespace command in the HAWQ documentation is misleading. The users are told to replace “default” in the command with the current non-HA HDFS URI. But the same utility does not accept any other value than the “default” keyword. 

hawq filespace --movefilespace default --location=hdfs://hdfs-cluster/hawq_new_filespace

Resolution

We have to move the HAWQ file space from the old HDFS URI to the HA enabled HDFS URI. 

Old HDFS location: hdfs://hdm1.hdp.local/hawq_data (Default)

New HDFS location: hdfs://pivotalhdfs/hawq_data (HA enabled)

The following command will fail if we try to move the HDFS location to enable HAWQ to work with Namenode HA:

hawq filespace - - movefilespace hdfs://hdm1.hdp.local/hawq_data - -location =hdfs://pivotalhdfs/hawq_data

Instead, if we replace the prior location with “default,” utility will run and enable HAWQ with Namenode HA.

hawq filespace - - movefilespace default - -location =hdfs://pivotalhdfs/hawq_data