Scenarios

Handle errors that occurred during data import.

Querying Error Information

Errors that arise during data import are categorized as either data format errors or non-data format errors. The error table records only data format errors.

Data format error

When creating a foreign table, specify LOG INTO error_table_name. Data format errors occurring during the data import will be written into the specified table. You can run the following SQL statement to query error details:

SELECT * FROM error_table_name;

Table 1 lists the columns of the error_table_name table.

**Table 1** Columns in the *error_table_name* table
Column	Type	Description
nodeid	integer	ID of the node where an error is reported
begintime	timestamp with time zone	Time when a data format error is reported
filename	character varying	Name of the source data file where a data format error occurs If you use GDS for importing data, the error information includes the IP address and port number of the GDS server.
rownum	bigint	Number of the row where an error occurs in a source data file
rawrecord	text	Raw record of the data format error in the source data file
detail	text	Error details

Non-data format error
If a non-data format error occurs during data import, the entire process is halted. During data import, you can identify and correct errors by reviewing the displayed error information.

Handling data import errors

Troubleshoot data import errors based on obtained error information and the description in the following table.

Table 2 Handling data import errors

Error Information

Error Type

Cause

Solution

missing data for column "r_reason_desc"

Format error

The number of columns in the source data file is less than that in the foreign table.
In a TEXT format source data file, an escape character (for example, \) leads to delimiter or quote mislocation.
Example: The target table contains three columns as shown in the following command output. The escape character (\) converts the delimiter (|) into the value of the second column, causing loss of the value of the third column.
```
BE|Belgium\|1
```

If an error is reported due to missing columns, perform the following operations:
- Add the r_reason_desc column to the source data file.
- When creating a foreign table, set the parameter fill_missing_fields to on. In this way, if the last column of a row in the source data file is missing, it is set to NULL and no error will be reported.
Check whether the row where an error occurred contains the escape character (\). If the row contains such a character, you are advised to set the parameter noescaping to true when creating a foreign table, indicating that the escape character (\) and the characters following it are not escaped.

extra data after last expected column

Format error

The number of columns in the source data file is greater than that in the foreign table.

Delete the unnecessary columns from the source data file.
When creating a foreign table, set the parameter ignore_extra_data to on. In this way, if the number of columns in a source data file is greater than that in the foreign table, the extra columns at the end of rows will not be imported.

invalid input syntax for type numeric: "a"

Format error

The data type is incorrect.

In the source data file, change the data type of the columns to be imported. If this error information is displayed, change the data type to numeric.

null value in column "staff_id" violates not-null constraint

Non-format error

The not-null constraint is violated.

In the source data file, add values to the specified columns. If this error information is displayed, add values to the staff_id column.

duplicate key value violates unique constraint "reg_id_pk"

Non-format error

The unique constraint is violated.

Delete the duplicate rows from the source data file.
Run the SELECT statement with the DISTINCT keyword to ensure that all imported rows are unique.
1
INSERT INTO reasons SELECT DISTINCT * FROM foreign_tpcds_reasons;

value too long for type character varying(16)

Format error

The column length exceeds the upper limit.

In the source data file, change the column length. If this error information is displayed, reduce the column length to no greater than 16 bytes (VARCHAR2).

Handling Import Errors

Scenarios

Querying Error Information

Handling data import errors