Fault Tolerance

exit_on_error

Parameter description: Specifies whether to terminate the current session.

Type: SUSET

Value range: Boolean

• on indicates that any error will terminate the current session.
• off indicates that only a FATAL error will terminate the current session.

Default value: off

omit_encoding_error

Parameter description: If this parameter is set to on and the client character set of the database is encoded in UTF-8 format, the occurring character encoding conversion errors will be recorded in logs. Additionally, converted characters that have conversion errors will be ignored and replaced with question marks (?).

Type: USERSET

Value range: Boolean

• on indicates that characters that have conversion errors will be ignored and replaced with question marks (?), and error information will be recorded in logs.
• off indicates that characters that have conversion errors cannot be converted and error information will be directly displayed.

Default value: off

max_query_retry_times

Parameter description: Specifies the maximum number of automatic retry times when an SQL statement error occurs. Currently, a statement can start retrying if the following errors occur: Connection reset by peer, Lock wait timeout, and Connection timed out. If this parameter is set to 0, the retry function is disabled.

Type: USERSET

Value range: an integer ranging from 0 to 20

Default value: 6

cn_send_buffer_size

Parameter description: Specifies the size of the data buffer used for data transmission on the CN.

Type: POSTMASTER

Value range: an integer ranging from 8 to 128. The unit is KB.

Default value: 8 KB

max_cn_temp_file_size

Parameter description: Specifies the maximum number of temporary files that can be used by the CN during automatic SQL statement retries. The value 0 indicates that no temporary file is used.

Type: SIGHUP

Value range: an integer ranging from 0 to 10485760. The unit is KB.

Default value: 5 GB

retry_ecode_list

Parameter description: Specifies the list of SQL error types that support automatic retry.

Type: USERSET

Value range: a string

Default value: YY001 YY002 YY003 YY004 YY005 YY006 YY007 YY008 YY009 YY010 YY011 YY012 YY013 YY014 YY015 53200 08006 08000 57P01 XX003 XX009 YY016 CG003 CG004 F0011 45003

data_sync_retry

Parameter description: Specifies whether to keep running the database when updated data fails to be written into disks by using the fsync function. In some OSs, no error is reported even if fsync has failed for multiple times. As a result, data is lost.

Type: POSTMASTER

Value range: Boolean

• on: The database keeps running and fsync is executed again after fsync fails.
• off: PANIC is reported and the database is stopped after fsync fails.

Default value: off