PostgreSQL Cursor Re-open error in GnuCOBOL - postgresql

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.