CLIENT_ERRORS_SUMMARY_GLOBAL

The table CLIENT_ERRORS_SUMMARY_GLOBAL provides a global summary of all SQL errors and warnings that have been returned to clients that connect to a TiDB server. These include:

  • Malformed SQL statements.
  • Division by zero errors.
  • The attempt to insert out-of-range of duplicate key values.
  • Permission errors.
  • A table does not exist.

Client errors are returned to the client via the MySQL server protocol, where applications are expected to take appropriate action. The INFORMATION_SCHEMA.CLIENT_ERRORS_SUMMARY_GLOBAL table provides a high-level overview, and is useful in the scenario where applications are not correctly handling (or logging) errors returned by the TiDB server.

The summarized counts can be reset with the statement FLUSH CLIENT_ERRORS_SUMMARY. The summary is local to each TiDB server and is only retained in memory. Summaries will be lost if the TiDB server restarts.

  1. USE INFORMATION_SCHEMA;
  2. DESC CLIENT_ERRORS_SUMMARY_GLOBAL;

The output is as follows:

  1. +---------------+---------------+------+------+---------+-------+
  2. | Field         | Type          | Null | Key  | Default | Extra |
  3. +---------------+---------------+------+------+---------+-------+
  4. | ERROR_NUMBER  | bigint(64)    | NO   |      | NULL    |       |
  5. | ERROR_MESSAGE | varchar(1024) | NO   |      | NULL    |       |
  6. | ERROR_COUNT   | bigint(64)    | NO   |      | NULL    |       |
  7. | WARNING_COUNT | bigint(64)    | NO   |      | NULL    |       |
  8. | FIRST_SEEN    | timestamp     | YES  |      | NULL    |       |
  9. | LAST_SEEN     | timestamp     | YES  |      | NULL    |       |
  10. +---------------+---------------+------+------+---------+-------+
  11. 6 rows in set (0.00 sec)

Field description:

  • ERROR_NUMBER: The MySQL-compatible error number that was returned.
  • ERROR_MESSAGE: The error message which matches the error number (in prepared statement form).
  • ERROR_COUNT: The number of times this error was returned.
  • WARNING_COUNT: The number of times this warning was returned.
  • FIRST_SEEN: The first time this error (or warning) was sent.
  • LAST_SEEN: The most recent time this error (or warning) was sent.

The following example shows a warning being generated when connecting to a local TiDB server. The summary is reset after executing FLUSH CLIENT_ERRORS_SUMMARY:

  1. SELECT 0/0;
  2. SELECT * FROM CLIENT_ERRORS_SUMMARY_GLOBAL;
  3. FLUSH CLIENT_ERRORS_SUMMARY;
  4. SELECT * FROM CLIENT_ERRORS_SUMMARY_GLOBAL;

The output is as follows:

  1. +-----+
  2. | 0/0 |
  3. +-----+
  4. | NULL |
  5. +-----+
  6. 1 row in set, 1 warning (0.00 sec)
  8. +--------------+---------------+-------------+---------------+---------------------+---------------------+
  9. | ERROR_NUMBER | ERROR_MESSAGE | ERROR_COUNT | WARNING_COUNT | FIRST_SEEN          | LAST_SEEN           |
  10. +--------------+---------------+-------------+---------------+---------------------+---------------------+
  11. |         1365 | Division by 0 |           0 |             1 | 2021-03-18 13:10:51 | 2021-03-18 13:10:51 |
  12. +--------------+---------------+-------------+---------------+---------------------+---------------------+
  13. 1 row in set (0.00 sec)
  15. Query OK, 0 rows affected (0.00 sec)
  17. Empty set (0.00 sec)