Helm installation failed when enabling database option

When using below env configuration for kong helm chart

        plugins: "bundled,oidc,key-auth"
        database: postgres
        pg_host: "" 
        pg_user: "keycloak"                  
        pg_password: "4IgojOOd4W"
        pg_database: "kong"  

Getting response as >> pre-upgrade hooks failed:

Please suggest a possible reason for this and if you can point to solution for this.

Thanks & Regards
Software Engineer, Fynarfin Pvt Ltd

Please post error log for more details