PostgreSQL Cursor Re-open error in GnuCOBOL

Question

I am trying to move from Oracle to PostgreSQL on GnuCOBOL. I have a piece of code which uses cursors and need opening a cursor multiple times. However when trying to open the cursor again I get the error ERROR: cursor "fetchtbl_c1" already exists

        IDENTIFICATION              DIVISION.
        PROGRAM-ID.                 FETCHTBL.

        DATA                        DIVISION.
        WORKING-STORAGE             SECTION.
        01  D-SOC-REC.
            05  D-SOC-NO-1          PIC  X(3).
            05  FILLER              PIC  X.
            05  D-SOC-NO-2          PIC  X(3).

        EXEC SQL BEGIN DECLARE SECTION END-EXEC.
        01  USERNAME                PIC  X(30) VALUE SPACE.
        01  SOC-REC-VARS.
            05  SOC-NO-1            PIC X(3).
            05  SOC-NO-2            PIC X(3).
        EXEC SQL END DECLARE SECTION END-EXEC.

        EXEC SQL INCLUDE SQLCA END-EXEC.
        PROCEDURE                   DIVISION.
        MAIN-RTN.
            MOVE  SPACE             TO   USERNAME.
            EXEC SQL
                CONNECT :USERNAME
            END-EXEC.
            IF  SQLCODE NOT = ZERO DISPLAY "ERROR CONNECTING".

       *    DECLARE CURSOR
            EXEC SQL
                DECLARE C1 CURSOR FOR
                SELECT SOC_NO_1, SOC_NO_2
                       FROM INSP
                       ORDER BY SOC_NO_1
            END-EXEC.
            EXEC SQL
                OPEN C1
            END-EXEC.
            IF SQLCODE = ZERO DISPLAY "OPEN SUCCESSFUL"
            ELSE DISPLAY "OPEN FAILED".

       *    FETCH
            EXEC SQL
                FETCH C1 INTO :SOC-NO-1,:SOC-NO-2
            END-EXEC.
            IF SQLCODE = ZERO DISPLAY "FETCH SUCCESSFUL"
            ELSE DISPLAY "FETCH FAILED".
            PERFORM UNTIL SQLCODE NOT = ZERO
               MOVE  SOC-NO-1      TO    D-SOC-NO-1
               MOVE  SOC-NO-2      TO    D-SOC-NO-2
               DISPLAY D-SOC-REC
               EXEC SQL
                   FETCH C1 INTO :SOC-NO-1,:SOC-NO-2
               END-EXEC
            END-PERFORM.

       *    CLOSE CURSOR
            EXEC SQL
                CLOSE C1
            END-EXEC.
            IF SQLCODE = ZERO DISPLAY "CLOSE SUCCESSFUL"
            ELSE DISPLAY "CLOSE FAILED".

       *    OPEN AGAIN
            EXEC SQL
                OPEN C1
            END-EXEC.
            IF SQLCODE = ZERO DISPLAY "REOPEN SUCCESSFUL"
            ELSE DISPLAY "REOPEN FAILED " SQLERRMC.
       *    COMMIT
            EXEC SQL
                COMMIT WORK
            END-EXEC.

       *    DISCONNECT
            EXEC SQL
                DISCONNECT ALL
            END-EXEC.

       *    END
            STOP RUN.

Pre-compiled the code using ocesql and compiled using cobc -x

Postgres Output

OPEN SUCCESSFUL
FETCH SUCCESSFUL
003 001
005 001
CLOSE SUCCESSFUL
REOPEN FAILED ERROR:  cursor "fetchtbl_c1" already exists

The above code works perfectly fine (except for connection part) in Oracle.

Oracle output

OPEN SUCCESSFUL
FETCH SUCCESSFUL
003 001
CLOSE SUCCESSFUL
REOPEN SUCCESSFUL

I have tried searching on the internet but without any luck. Anybody can help me with this? I am using PostgreSQL version 10.3 and GnuCOBOL version 2.2.0.

Answer 1

There seemed to be an issue with ocesql pre-compiler. I have put a fix in ocdb.c in function OCDBSetResultStatus to return a successful code in case there is not result resource (which happens for open cursor case).

This might not be entirely correct but after spending a few hours testing I see this working fine.

Code changes:

int
OCDBSetResultStatus(int id, struct sqlca_t *st){
    struct s_conn *p_conn;
    int retval;

    p_conn = look_up_conn_lists(id);
    if(p_conn == NULL){
      //return OCDB_RES_FATAL_ERROR;
        return RESULT_ERROR;
    }
    if(p_conn->resaddr == OCDB_RES_DEFAULT_ADDRESS){
        // 結果リソースが無いため成功で返す
        // Ankit: uncommented since there is no result resource,
        //        (true in case of open cursor)
        return OCDB_RES_COMMAND_OK;
        //return RESULT_ERROR;
    }

#ifdef PGSQL_MODE_ON
    retval = OCDB_PGSetResultStatus(p_conn->resaddr,st);
#endif
    return retval;
}

Let me know if anybody faces any issues because of this change.