@Override
    public SqlSchema getSqlSchema() {
      String schemaStr = this.getSchema(this.systemStream);
      Schema schema = Schema.parse(schemaStr);
      AvroTypeFactoryImpl avroTypeFactory = new AvroTypeFactoryImpl();
      return avroTypeFactory.createType(schema);
    }
Relational schemas provider which reads system schema from a given directory
samza-sql-shell/src/main/java/org/apache/samza/sql/client/impl/FileSystemAvroRelSchemaProviderFactory.java