Cloudera server fails after migrating from postgres to Oracle

[#1]

Hi,

We have a CDH cluster with version 5.15 and we have migrated the db used by Cloudera from postgres to Oracle. We have followed the migration steps and took the cluster down. When we tried to start the cloudera server again it's failing with the below error. 

022-01-13 09:53:19,028 INFO main:com.cloudera.enterprise.dbutil.DbUtil: Schema version table already exists.
2022-01-13 09:53:19,029 INFO main:com.cloudera.enterprise.dbutil.DbUtil: DB Schema version 51300.
2022-01-13 09:53:19,029 INFO main:com.cloudera.enterprise.dbutil.DbUtil: Current database schema version: 51300
WARN main:com.cloudera.server.cmf.bootstrap.EntityManagerFactoryBean: Failed to determine prior version. This is expected if you are starting Cloudera Manager for the first time. Please also ignore any error messages about missing tables. Moving ahead assuming no upgrade: org.hibernate.MappingException: No Dialect mapping for JDBC type: -9

2022-01-13 09:53:19,043 ERROR main:com.cloudera.server.cmf.bootstrap.EntityManagerFactoryBean: Unable to access schema version in database.
javax.persistence.PersistenceException: org.hibernate.MappingException: No Dialect mapping for JDBC type: -9 

Not to mention that when we ran the script scm_prepare_database script we were table to see a successful connection with the db. How can we solve this issue?

Oracle version: 19c 

Regards

[#2]

2022-01-13 09:53:19,043 ERROR main:com.cloudera.server.cmf.bootstrap.EntityManagerFactoryBean: Unable to access schema version in database.
It says unable to access the schema version from the database.

Can you access the scm databsase and check the version 

scm=> select * from SCHEMA_VERSION;

version | old_version

---------+-------------

   |      

[#3 · Accepted solution]

Hi,

It was already able to access the SCHEMA_VERSION Table and get the record from the table. Solved the problem by downgrading the db version.

Regards