The file: common/src/main/java/io/druid/common/config/ConfigManager.java has a line:

this.insertStatement = String.format(
"INSERT INTO %s (name, payload) VALUES (:name, :payload) ON DUPLICATE KEY UPDATE payload = :payload",
configTable
);

The statement "ON DUPLICATE KEY UPDATE" is not valid for postgresql.

Could it be compatible with both (mysql and postgersql) ??