Converting a CSV to ORC files usually takes a Hadoop cluster to perform the task. Since I only wanted to convert files for later uploading into an existing cluster, I tried some different approach. Searching for some tool to do the task, I arrived at Apache NiFi.

Here is the flow I used to transform my data. nifi flow

  • step 1 - list all exiting CSV files
  • step 2 - read each file into memory
  • step 3 - convert content into AVRO
    • sadly AVRO needs a schema of you data to do the actual conversion. so here is the simple schema I used for my data:
{
  "name": "jobs",
  "type": "record",
  "fields": [
    {"name":"jobStart","type": "string"},
    {"name":"jobEnd","type": "string"},
    {"name":"logId","type": "string"},
    {"name":"corrid","type": "string"},
    {"name":"parentid","type": "string"},
    {"name":"jobId","type": "string"},
    {"name":"process","type": "string"},
    {"name":"machine","type": "string"},
    {"name":"duration","type": ["null","long"]},
    {"name":"status","type": "string"},
    {"name":"domain","type": "string"},
    {"name":"deployment","type": "string"},
    {"name":"engine","type": "string"}
  ]
}
  • step 4 - convert AVRO to ORC
  • step 5 - UpdateAttribute: set the target filename
  • step 6 - write the ORC file to the target location

Here is the NiFi flow I used. You will have to change the file locations and data schema to really use it.

CsvToOrc template