select语里里的function的读一致性问题

建立测试表test

DROP TABLE TEST;
/
CREATE TABLE TEST AS SELECT SYSDATE AS T1 FROM DUAL
/
SET TIMING ON

第一个试验，不加DETERMINISTIC 传入参数不一样

CREATE OR REPLACE FUNCTION F_SCN(V_VAL NUMBER) RETURN VARCHAR2
 --DETERMINISTIC
 AS
  V_DATE DATE := SYSDATE + 3 / 24 / 60 / 60;
  V_SCN  NUMBER;
  V_T1   TEST.T1%TYPE;
BEGIN
  V_SCN := DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER;
  SELECT MAX(T1) INTO V_T1 FROM TEST WHERE ROWNUM <=1;
  LOOP
     EXIT WHEN SYSDATE >= V_DATE;
  END LOOP;
  RETURN TO_CHAR(V_T1, 'HH24:MI:SS') || '->' || TO_CHAR(V_SCN) || '->' || TO_CHAR(SCN_TO_TIMESTAMP(V_SCN), 'HH24:MI:SS') || '->' || TO_CHAR(SYSDATE, 'HH24:MI:SS');
END;
/

BEGIN
  DBMS_SCHEDULER.CREATE_JOB(JOB_NAME   => 'TEST_JOB',
                            JOB_TYPE   => 'PLSQL_BLOCK',
                            JOB_ACTION => 'DECLARE
    V_DATE DATE := SYSDATE + 18 / 24 / 60 / 60;
  BEGIN
    LOOP
      UPDATE TEST SET T1 = SYSDATE;
      COMMIT;
      DBMS_LOCK.SLEEP(3);
      EXIT WHEN SYSDATE >= V_DATE;
    END LOOP;
  END;',
                            START_DATE => SYSDATE,
                            ENABLED    => TRUE,
                            AUTO_DROP  => TRUE);
  DBMS_LOCK.SLEEP(5);
END;
/

COL SCN1_____SCNTIME___SYSDATE FORMAT A30
COL T1_SCN2_____SCNTIME___SYSDATE FORMAT A40

/*FUNCTION传入参数一不样*/
SELECT TO_CHAR(DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER) ||
       '->' || TO_CHAR(SCN_TO_TIMESTAMP(DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER), 'HH24:MI:SS') ||
       '->' || TO_CHAR(SYSDATE, 'HH24:MI:SS') AS SCN1_____SCNTIME___SYSDATE,
       F_SCN(LEVEL) AS T1_SCN2_____SCNTIME___SYSDATE
  FROM DUAL
CONNECT BY LEVEL <= 5;

SCN1_____SCNTIME___SYSDATE     T1_SCN2_____SCNTIME___SYSDATE
------------------------------ ----------------------------------------
2201784->14:08:01->14:08:03    14:08:01->2201784->14:08:01->14:08:06
2201787->14:08:04->14:08:03    14:08:04->2201787->14:08:04->14:08:09
2201790->14:08:07->14:08:03    14:08:07->2201790->14:08:07->14:08:12
2201793->14:08:10->14:08:03    14:08:10->2201793->14:08:10->14:08:15
2201796->14:08:13->14:08:03    14:08:13->2201796->14:08:13->14:08:18
Executed in 14.813 seconds

第二个试验，不加DETERMINISTIC 但传入参数一样

CREATE OR REPLACE FUNCTION F_SCN(V_VAL NUMBER) RETURN VARCHAR2
 --DETERMINISTIC
 AS
  V_DATE DATE := SYSDATE + 3 / 24 / 60 / 60;
  V_SCN  NUMBER;
  V_T1   TEST.T1%TYPE;
BEGIN
  V_SCN := DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER;
  SELECT MAX(T1) INTO V_T1 FROM TEST WHERE ROWNUM <=1;
  LOOP
     EXIT WHEN SYSDATE >= V_DATE;
  END LOOP;
  RETURN TO_CHAR(V_T1, 'HH24:MI:SS') || '->' || TO_CHAR(V_SCN) || '->' || TO_CHAR(SCN_TO_TIMESTAMP(V_SCN), 'HH24:MI:SS') || '->' || TO_CHAR(SYSDATE, 'HH24:MI:SS');
END;
/

BEGIN
  DBMS_SCHEDULER.CREATE_JOB(JOB_NAME   => 'TEST_JOB',
                            JOB_TYPE   => 'PLSQL_BLOCK',
                            JOB_ACTION => 'DECLARE
    V_DATE DATE := SYSDATE + 18 / 24 / 60 / 60;
  BEGIN
    LOOP
      UPDATE TEST SET T1 = SYSDATE;
      COMMIT;
      DBMS_LOCK.SLEEP(3);
      EXIT WHEN SYSDATE >= V_DATE;
    END LOOP;
  END;',
                            START_DATE => SYSDATE,
                            ENABLED    => TRUE,
                            AUTO_DROP  => TRUE);
  DBMS_LOCK.SLEEP(5);
END;
/

COL SCN1_____SCNTIME___SYSDATE FORMAT A30
COL T1_SCN2_____SCNTIME___SYSDATE FORMAT A40

/*FUNCTION传入参数一样*/
SELECT TO_CHAR(DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER) ||
       '->' || TO_CHAR(SCN_TO_TIMESTAMP(DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER), 'HH24:MI:SS') ||
       '->' || TO_CHAR(SYSDATE, 'HH24:MI:SS') AS SCN1_____SCNTIME___SYSDATE,
       F_SCN(1) AS T1_SCN2_____SCNTIME___SYSDATE
  FROM DUAL
CONNECT BY LEVEL <= 5;

SCN1_____SCNTIME___SYSDATE     T1_SCN2_____SCNTIME___SYSDATE
------------------------------ ----------------------------------------
2202369->14:11:09->14:11:11    14:11:09->2202369->14:11:09->14:11:14
2202372->14:11:12->14:11:11    14:11:12->2202372->14:11:12->14:11:17
2202375->14:11:15->14:11:11    14:11:15->2202375->14:11:15->14:11:20
2202378->14:11:18->14:11:11    14:11:18->2202378->14:11:18->14:11:23
2202381->14:11:21->14:11:11    14:11:21->2202381->14:11:21->14:11:26
Executed in 14.641 seconds

第三个实验 使用参数DETERMINISTIC 传入参数不一样

CREATE OR REPLACE FUNCTION F_SCN(V_VAL NUMBER) RETURN VARCHAR2
 DETERMINISTIC
 AS
  V_DATE DATE := SYSDATE + 3 / 24 / 60 / 60;
  V_SCN  NUMBER;
  V_T1   TEST.T1%TYPE;
BEGIN
  V_SCN := DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER;
  SELECT MAX(T1) INTO V_T1 FROM TEST WHERE ROWNUM <=1;
  LOOP
     EXIT WHEN SYSDATE >= V_DATE;
  END LOOP;
  RETURN TO_CHAR(V_T1, 'HH24:MI:SS') || '->' || TO_CHAR(V_SCN) || '->' || TO_CHAR(SCN_TO_TIMESTAMP(V_SCN), 'HH24:MI:SS') || '->' || TO_CHAR(SYSDATE, 'HH24:MI:SS');
END;
/

BEGIN
  DBMS_SCHEDULER.CREATE_JOB(JOB_NAME   => 'TEST_JOB',
                            JOB_TYPE   => 'PLSQL_BLOCK',
                            JOB_ACTION => 'DECLARE
    V_DATE DATE := SYSDATE + 18 / 24 / 60 / 60;
  BEGIN
    LOOP
      UPDATE TEST SET T1 = SYSDATE;
      COMMIT;
      DBMS_LOCK.SLEEP(3);
      EXIT WHEN SYSDATE >= V_DATE;
    END LOOP;
  END;',
                            START_DATE => SYSDATE,
                            ENABLED    => TRUE,
                            AUTO_DROP  => TRUE);
  DBMS_LOCK.SLEEP(5);
END;
/

COL SCN1_____SCNTIME___SYSDATE FORMAT A30
COL T1_SCN2_____SCNTIME___SYSDATE FORMAT A40

/*FUNCTION传入参数一不样*/
SELECT TO_CHAR(DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER) ||
       '->' || TO_CHAR(SCN_TO_TIMESTAMP(DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER), 'HH24:MI:SS') ||
       '->' || TO_CHAR(SYSDATE, 'HH24:MI:SS') AS SCN1_____SCNTIME___SYSDATE,
       F_SCN(LEVEL) AS T1_SCN2_____SCNTIME___SYSDATE
  FROM DUAL
CONNECT BY LEVEL <= 5;

SCN1_____SCNTIME___SYSDATE     T1_SCN2_____SCNTIME___SYSDATE
------------------------------ ----------------------------------------
2202453->14:12:54->14:12:56    14:12:54->2202453->14:12:54->14:12:59
2202456->14:12:57->14:12:56    14:12:57->2202456->14:12:57->14:13:02
2202459->14:13:00->14:12:56    14:13:00->2202459->14:13:00->14:13:05
2202462->14:13:03->14:12:56    14:13:03->2202462->14:13:03->14:13:08
2202465->14:13:06->14:12:56    14:13:06->2202465->14:13:06->14:13:11
Executed in 14.578 seconds

第四个实验 使用参数DETERMINISTIC 传入参数一样

CREATE OR REPLACE FUNCTION F_SCN(V_VAL NUMBER) RETURN VARCHAR2
 DETERMINISTIC
 AS
  V_DATE DATE := SYSDATE + 3 / 24 / 60 / 60;
  V_SCN  NUMBER;
  V_T1   TEST.T1%TYPE;
BEGIN
  V_SCN := DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER;
  SELECT MAX(T1) INTO V_T1 FROM TEST WHERE ROWNUM <=1;
  LOOP
     EXIT WHEN SYSDATE >= V_DATE;
  END LOOP;
  RETURN TO_CHAR(V_T1, 'HH24:MI:SS') || '->' || TO_CHAR(V_SCN) || '->' || TO_CHAR(SCN_TO_TIMESTAMP(V_SCN), 'HH24:MI:SS') || '->' || TO_CHAR(SYSDATE, 'HH24:MI:SS');
END;
/

BEGIN
  DBMS_SCHEDULER.CREATE_JOB(JOB_NAME   => 'TEST_JOB',
                            JOB_TYPE   => 'PLSQL_BLOCK',
                            JOB_ACTION => 'DECLARE
    V_DATE DATE := SYSDATE + 18 / 24 / 60 / 60;
  BEGIN
    LOOP
      UPDATE TEST SET T1 = SYSDATE;
      COMMIT;
      DBMS_LOCK.SLEEP(3);
      EXIT WHEN SYSDATE >= V_DATE;
    END LOOP;
  END;',
                            START_DATE => SYSDATE,
                            ENABLED    => TRUE,
                            AUTO_DROP  => TRUE);
  DBMS_LOCK.SLEEP(5);
END;
/

COL SCN1_____SCNTIME___SYSDATE FORMAT A30
COL T1_SCN2_____SCNTIME___SYSDATE FORMAT A40

/*FUNCTION传入参数一样*/
SELECT TO_CHAR(DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER) ||
       '->' || TO_CHAR(SCN_TO_TIMESTAMP(DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER), 'HH24:MI:SS') ||
       '->' || TO_CHAR(SYSDATE, 'HH24:MI:SS') AS SCN1_____SCNTIME___SYSDATE,
       F_SCN(1) AS T1_SCN2_____SCNTIME___SYSDATE
  FROM DUAL
CONNECT BY LEVEL <= 5;

SCN1_____SCNTIME___SYSDATE     T1_SCN2_____SCNTIME___SYSDATE
------------------------------ ----------------------------------------
2202526->14:14:46->14:14:49    14:14:47->2202526->14:14:46->14:14:52
2202529->14:14:49->14:14:49    14:14:47->2202526->14:14:46->14:14:52
2202529->14:14:49->14:14:49    14:14:47->2202526->14:14:46->14:14:52
2202529->14:14:49->14:14:49    14:14:47->2202526->14:14:46->14:14:52
2202529->14:14:49->14:14:49    14:14:47->2202526->14:14:46->14:14:52
Executed in 3 seconds

可以看到，在传入固定参数时，DETERMINISTIC作用很大