## Appendix D. Error Code

**ErrorCode**

```protobuf
enum ErrorCode {
  SUCCESS = 0;
  UNEXPECTED_ERROR = 1;
  CONNECT_FAILED = 2;
  PERMISSION_DENIED = 3;
  COLLECTION_NOT_EXISTS = 4;
  ILLEGAL_ARGUMENT = 5;
  ILLEGAL_DIMENSION = 7;
  ILLEGAL_INDEX_TYPE = 8;
  ILLEGAL_COLLECTION_NAME = 9;
  ILLEGAL_TOPK = 10;
  ILLEGAL_ROWRECORD = 11;
  ILLEGAL_VECTOR_ID = 12;
  ILLEGAL_SEARCH_RESULT = 13;
  FILE_NOT_FOUND = 14;
  META_FAILED = 15;
  CACHE_FAILED = 16;
  CANNOT_CREATE_FOLDER = 17;
  CANNOT_CREATE_FILE = 18;
  CANNOT_DELETE_FOLDER = 19;
  CANNOT_DELETE_FILE = 20;
  BUILD_INDEX_ERROR = 21;
  ILLEGAL_NLIST = 22;
  ILLEGAL_METRIC_TYPE = 23;
  OUT_OF_MEMORY = 24;

  // internal error code.
  DD_REQUEST_RACE = 1000;
}
```