SQL5197N or SQL5199N error during INSERT or SELECT operations in Db2 Big SQL

INSERT or SELECT statements running after the number of worker pods were scaled down might fail.

Symptoms

Insert or select operations fail with SQL5197N or SQL5199N. For example:
DB21034E The command was processed as an SQL statement because it was not a valid Command Line 
Processor command. During SQL processing it returned: SQL5199N The statement failed because a 
connection to a Hadoop/External Table I/O component could not be established or maintained. 
Hadoop/External Table I/O component name: "SCHEDULER". Reason code: "1". Database partition number: "0". 
SQLSTATE=57067

SQL5197N The statement failed because of a communication error with a Db2 Big SQL component. 
Big SQL component name: "SCHEDULER". Reason code: "1". Log entry identifier: "DB2". SQLSTATE=57066

Resolving the problem

To resolve this problem, restart the Db2 Big SQL instance by completing the following steps:
  1. Log in to Red Hat® OpenShift® Container Platform as an instance administrator.
    ${OC_LOGIN}
    Remember: OC_LOGIN is an alias for the oc login command.
  2. Change to the project where the IBM® Software Hub control plane is installed:
    oc project ${PROJECT_CPD_INST_OPERANDS}
  3. Identify the Db2 Big SQL instance ID:
    oc get cm -l component=db2bigsql -o custom-columns="Instance Id:{.data.instance_id},Instance Name:{.data.instance_name},Created:{.metadata.creationTimestamp}"
  4. Get the name of the Db2 Big SQL head pod:
    head_pod=$(oc get pod -l app=bigsql-<instance_id>,name=dashmpp-head-0 --no-headers=true -o=custom-columns=NAME:.metadata.name)
  5. Restart Db2 Big SQL:
    oc exec -i $head_pod -- sudo su - db2inst1 -c "bigsql stop; bigsql start"