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# Appendix 3: Status Codes

**Status Code** is introduced in the latest version. A sample solution as IoTDB requires registering the time series first before writing data is:

```
try {
    writeData();
} catch (SQLException e) {
  // the most case is that the time series does not exist
  if (e.getMessage().contains("exist")) {
      //However, using the content of the error message is not so efficient
      registerTimeSeries();
      //write data once again
      writeData();
  }
}

```

With Status Code, instead of writing codes like `if (e.getErrorMessage().contains("exist"))`, we can simply use `e.getErrorCode() == TSStatusCode.TIME_SERIES_NOT_EXIST_ERROR.getStatusCode()`.

Here is a list of Status Code and related message:

|Status Code|Status Type|Meanings|
|:---|:---|:---|
|200|SUCCESS_STATUS||
|201|STILL_EXECUTING_STATUS||
|202|INVALID_HANDLE_STATUS||
|203|INCOMPATIBLE_VERSION|Incompatible version|
|298|NODE_DELETE_FAILED_ERROR|Failed while deleting node|
|299|ALIAS_ALREADY_EXIST_ERROR|Alias already exists|
|300|PATH_ALREADY_EXIST_ERROR|Path already exists|
|301|PATH_NOT_EXIST_ERROR|Path does not exist|
|302|UNSUPPORTED_FETCH_METADATA_OPERATION_ERROR|Unsupported fetch metadata operation|
|303|METADATA_ERROR|Meet error when dealing with metadata|
|305|OUT_OF_TTL_ERROR|Insertion time is less than TTL time bound|
|306|CONFIG_ADJUSTER|IoTDB system load is too large|
|307|MERGE_ERROR|Meet error while merging|
|308|SYSTEM_CHECK_ERROR|Meet error while system checking|
|309|SYNC_DEVICE_OWNER_CONFLICT_ERROR|Sync device owners conflict|
|310|SYNC_CONNECTION_EXCEPTION|Meet error while sync connecting|
|311|STORAGE_GROUP_PROCESSOR_ERROR|Storage group processor related error|
|312|STORAGE_GROUP_ERROR|Storage group related error|
|313|STORAGE_ENGINE_ERROR|Storage engine related error|
|314|TSFILE_PROCESSOR_ERROR|TsFile processor related error|
|315|PATH_ILLEGAL|Illegal path|
|316|LOAD_FILE_ERROR|Meet error while loading file|
|317|STORAGE_GROUP_NOT_READY| The storage group is in recovery mode, not ready fore accepting read/write operation|
|400|EXECUTE_STATEMENT_ERROR|Execute statement error|
|401|SQL_PARSE_ERROR|Meet error while parsing SQL|
|402|GENERATE_TIME_ZONE_ERROR|Meet error while generating time zone|
|403|SET_TIME_ZONE_ERROR|Meet error while setting time zone|
|404|NOT_STORAGE_GROUP_ERROR|Operating object is not a storage group|
|405|QUERY_NOT_ALLOWED|Query statements are not allowed error|
|406|AST_FORMAT_ERROR|AST format related error|
|407|LOGICAL_OPERATOR_ERROR|Logical operator related error|
|408|LOGICAL_OPTIMIZE_ERROR|Logical optimize related error|
|409|UNSUPPORTED_FILL_TYPE_ERROR|Unsupported fill type related error|
|410|PATH_ERROR|Path related error|
|411|QUERY_PROCESS_ERROR|Query process related error|
|412|WRITE_PROCESS_ERROR|Writing data related error|
|413|WRITE_PROCESS_REJECT|Writing data rejected error|
|414|QUERY_ID_NOT_EXIST|Kill query with non existent queryId|
|500|INTERNAL_SERVER_ERROR|Internal server error|
|501|CLOSE_OPERATION_ERROR|Meet error in close operation|
|502|READ_ONLY_SYSTEM_ERROR|Operating system is read only|
|503|DISK_SPACE_INSUFFICIENT_ERROR|Disk space is insufficient|
|504|START_UP_ERROR|Meet error while starting up|
|505|SHUT_DOWN_ERROR|Meet error while shutdown|
|506|MULTIPLE_ERROR|Meet error when executing multiple statements|
|600|WRONG_LOGIN_PASSWORD_ERROR|Username or password is wrong|
|601|NOT_LOGIN_ERROR|Has not logged in|
|602|NO_PERMISSION_ERROR|No permissions for this operation|
|603|UNINITIALIZED_AUTH_ERROR|Uninitialized authorizer|
|700|PARTITION_NOT_READY|Partition table not ready|
|701|TIME_OUT|Operation timeout|
|702|NO_LEADER|No leader|
|703|UNSUPPORTED_OPERATION|Unsupported operation|
|704|NODE_READ_ONLY|Node read only|
|705|CONSISTENCY_FAILURE|Consistency check failure|
|706|NO_CONNECTION|Can not get connection error|
|707|NEED_REDIRECTION|Need direction|

> All exceptions are refactored in latest version by extracting uniform message into exception classes. Different error codes are added to all exceptions. When an exception is caught and a higher-level exception is thrown, the error code will keep and pass so that users will know the detailed error reason.
A base exception class "ProcessException" is also added to be extended by all exceptions.