Debugging

Syntax

RAISE

The syntax of RAISE is as follows:

Figure 1 raise_format::=

Figure 2 raise_condition::=

Figure 3 raise_sqlstate::=

Figure 4 raise_option::=

Figure 5 raise::=

Parameter description:

  • The level option is used to specify the error level, that is, DEBUG, LOG, INFO, NOTICE, WARNING, or EXCEPTION (default). EXCEPTION throws an error that normally terminates the current transaction and the others only generate information at their levels. The log_min_messages and client_min_messages parameters control whether the error messages of specific levels are reported to the client and are written to the server log.

  • format: specifies the error message text to be reported, a format string. The format string can be appended with an expression for insertion to the message text. In a format string, % is replaced by the parameter value attached to format and %% is used to print %. For example:

    --v_job_id replaces % in the string.
    RAISE NOTICE 'Calling cs_create_job(%)',v_job_id;
    
  • option = expression: inserts additional information to an error report. The keyword option can be MESSAGE, DETAIL, HINT, or ERRCODE, and each expression can be any string.

    • MESSAGE: specifies the error message text. This option cannot be used in a RAISE statement that contains a format character string in front of USING.
    • DETAIL: specifies detailed information of an error.
    • HINT: prints hint information.
    • ERRCODE: designates an error code (SQLSTATE) to a report. A condition name or a five-character SQLSTATE error code can be used.
  • condition_name: specifies the condition name corresponding to the error code.

  • sqlstate: specifies the error code.

If neither a condition name nor an SQLSTATE is designated in a RAISE EXCEPTION command, the RAISE EXCEPTION (P0001) is used by default. If no message text is designated, the condition name or SQLSTATE is used as the message text by default.

NOTICE:

  • If the SQLSTATE designates an error code, the error code is not limited to a defined error code. It can be any error code containing five digits or ASCII uppercase rather than 00000. Do not use an error code ended with three zeros because such error codes are category codes and can be captured by the whole category.
  • In O-compatible mode, SQLCODE is equivalent to SQLSTATE.

NOTE: The syntax described in Figure 5 does not append any parameter. This form is used only for the EXCEPTION statement in a BEGIN block so that the error can be re-processed.

EXCEPTION_INIT

In O-compatible mode, EXCEPTION_INIT can be used to define the SQLCODE error code. The syntax is as follows:

Figure 6 exception_init::=

Parameter description:

  • exception_name indicates the name of the exception declared by the user. The EXCEPTION_INIT syntax must follow the declared exception.
  • sqlcode is a customized SQL code, which must be a negative integer ranging from –2147483647 to –1.

NOTICE: When EXCEPTION_INIT is used to customize an SQL code, SQLSTATE is equivalent to SQLCODE, and SQLERRM is in the format of xxx: non-GaussDB Exception. For example, if the customized SQL code is –1, SQLSTATE is –1 and SQLERRM is 1: non-GaussDB Exception.

Example

Display error and hint information when a transaction terminates:

CREATE OR REPLACE PROCEDURE proc_raise1(user_id in integer)
AS 
BEGIN 
RAISE EXCEPTION 'Noexistence ID --> %',user_id USING HINT = 'Please check your user ID'; 
END; 
/

call proc_raise1(300011);

-- Execution result:
ERROR:  Noexistence ID --> 300011
HINT:  Please check your user ID

Two methods are available for setting SQLSTATE:

CREATE OR REPLACE PROCEDURE proc_raise2(user_id in integer)
AS 
BEGIN 
RAISE 'Duplicate user ID: %',user_id USING ERRCODE = 'unique_violation'; 
END; 
/

\set VERBOSITY verbose
call proc_raise2(300011);

-- Execution result:
ERROR:  Duplicate user ID: 300011
SQLSTATE: 23505

If the main parameter is a condition name or SQLSTATE, the following applies:

RAISE division_by_zero;

RAISE SQLSTATE '22012';

For example:

CREATE OR REPLACE PROCEDURE division(div in integer, dividend in integer) 
AS 
DECLARE 
res int; 
    BEGIN 
    IF dividend=0 THEN 
        RAISE division_by_zero; 
        RETURN; 
    ELSE 
        res := div/dividend; 
        RAISE INFO 'division result: %', res;
        RETURN; 
    END IF; 
    END; 
/
call division(3,0);

-- Execution result:
ERROR:  division_by_zero

Alternatively:

RAISE unique_violation USING MESSAGE = 'Duplicate user ID: ' || user_id;

In O-compatible mode, EXCEPTION_INIT can be used to customize error codes SQLCODE.

declare
    deadlock_detected exception;
    pragma exception_init(deadlock_detected, -1);
begin
    if 1 > 0 then
        raise deadlock_detected;
    end if;
exception
    when deadlock_detected then
        raise notice 'sqlcode:%,sqlstate:%,sqlerrm:%',sqlcode,sqlstate,sqlerrm;
end;
/
-- Execution result:
NOTICE:  sqlcode:-1,sqlstate:-1,sqlerrm: 1: non-GaussDB Exception
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