Answer by Reguel Wermelinger

Reguel Wermelinger — Tue, 07 May 2019 04:28:40 -0400

The error occurs as ElasticSearch determines the type of a field once the first non empty value is defined. So if a BusinessData object with long expensesPtCurrent is once persistent, the type can be changed to String without facing compatiblity issues.

To takle the problem I'd write a conversion in Java to:

read old values (where the field was a long) as raw JSON
load and update the persistent businssData object and apply a compatible value in new format (String)
store the updated value in BusinessData repo

Sample:

public static void convertLegacy() throws IOException
  {
      ObjectMapper mapper = new ObjectMapper();
      BusinessDataRepository repository = BusinessDataRepository.get();
      List<BusinessDataInfo<Antrag>> infos = repository.search(Antrag.class).execute().getAllInfos();
      for(BusinessDataInfo<Antrag> info : infos)
      {
          String json = BusinessDataSearchIndex.toSearchIndexJson(info.getRawValue());
          JsonNode node = mapper.readTree(json); // JSON = simple API to work with JSON objects
          JsonNode ptCurr = node.get("lohnUndOderArbeitszeitaenderung").get("expensesPtCurrent");
          if (ptCurr.isLong())
          {
              // legacy value
              long oldVal = ptCurr.asLong();
              Antrag antrag = repository.find(info.getId(), Antrag.class);
              antrag.setExpensesCurrent(String.valueOf(oldVal)+ " CHF");
              repository.save(antrag);
          }
      }
  }

To avoid the problem at all:

Do not change the type of already persistent data. But add a new replacement field. Optionally with fallback support to read legacy values. See: https://answers.axonivy.com/questions/2606/can-not-persist-business-data-to-repo-after-changing-data-type

Answers to: ElasticSearch fails to recreate index due to data Field type change

Answer by Reguel Wermelinger