Given a string (normally representing an SQL statement), reduces it to the length given by the statement_truncate_len configuration option, and returns the result. No truncation occurs if the string is shorter than statement_truncate_len. Otherwise, the middle part of the string is replaced by an ellipsis (...).
This function is useful for formatting possibly lengthy statements retrieved from Performance Schema tables to a known fixed maximum length.
format_statement() operation can be modified using the following configuration options or their corresponding user-defined variables (see Section 28.4.2.1, “The sys_config Table”):
statement_truncate_len, @sys.statement_truncate_len
The maximum length of statements returned by the format_statement() function. Longer statements are truncated to this length. The default is 64.
By default, format_statement() truncates statements to be no more than 64 characters. Setting @sys.statement_truncate_len changes the truncation length for the current session:
mysql>SET @stmt = 'SELECT variable, value, set_time, set_by FROM sys_config';mysql>SELECT sys.format_statement(@stmt);+----------------------------------------------------------+ | sys.format_statement(@stmt) | +----------------------------------------------------------+ | SELECT variable, value, set_time, set_by FROM sys_config | +----------------------------------------------------------+ mysql>SET @sys.statement_truncate_len = 32;mysql>SELECT sys.format_statement(@stmt);+-----------------------------------+ | sys.format_statement(@stmt) | +-----------------------------------+ | SELECT variabl ... ROM sys_config | +-----------------------------------+