Oracle数据库排序后分页慢的问题

传统思路：

SELECT *
  FROM (SELECT TMP_PAGE.*, ROWNUM ROW_ID
          FROM (  SELECT LG.MESSAGE_ID messageId,
                         LG.PRODUCTION_ID productionId,
                         NVL (LG.PRODUCTION_NAME, '汇总控制')
                            productionName,
                         LG.RULE_ID ruleId,
                         LG.RULE_NAME ruleName,
                         LG.MESSAGE_CONTENT messageContent,
                         SUBSTR (LG.MESSAGE_CONTENT,
                                 0,
                                   INSTR (LG.MESSAGE_CONTENT,
                                          'br/>',
                                          1,
                                          1)
                                 - 2)
                            messageHead,
                         DECODE (LG.STEP,
                                 '0', '事前风控',
                                 '1', '事中监控',
                                 '过后巡检')
                            step,
                         LG.COMUPTE_DATE computeDate,
                         TO_CHAR (SG.SEND_TIME, 'yyyy/MM/dd HH24:mi:ss')
                            sendDate
                    FROM RC_MESSAGE_LOG LG
                         INNER JOIN RC_SEND_MESSAGE_LOG SG
                            ON LG.MESSAGE_SEND_LOG = SG.MESSAGE_SEND_LOG
                   WHERE     1 = 1
                         AND LG.STEP IN ('1', '2')
                         AND LG.COMUPTE_DATE >= 20171225
                         AND LG.COMUPTE_DATE <= 20180201
                        -- AND LG.STEP IN (?, ?)
                ORDER BY messageId DESC) TMP_PAGE
         WHERE ROWNUM <= 31570)
 WHERE ROW_ID > 31560

换一种思路：先根据条件取出rowId，而后根据rowId关联出对应的记录

SELECT LG.MESSAGE_ID messageId,
         LG.PRODUCTION_ID productionId,
         NVL (LG.PRODUCTION_NAME, '汇总控制')
            productionName,
         LG.RULE_ID ruleId,
         LG.RULE_NAME ruleName,
         LG.MESSAGE_CONTENT messageContent,
         SUBSTR (LG.MESSAGE_CONTENT,
                 0,
                   INSTR (LG.MESSAGE_CONTENT,
                          'br/>',
                          1,
                          1)
                 - 2)
            messageHead,
         DECODE (LG.STEP,
                 '0', '事前风控',
                 '1', '事中监控',
                 '过后巡检')
            step,
         LG.COMUPTE_DATE computeDate,
         TO_CHAR (SG.SEND_TIME, 'yyyy/MM/dd HH24:mi:ss')
            sendDate
    FROM RC_MESSAGE_LOG LG
         INNER JOIN RC_SEND_MESSAGE_LOG SG
            ON LG.MESSAGE_SEND_LOG = SG.MESSAGE_SEND_LOG,  
        (SELECT rid
          FROM (SELECT ROWNUM rn, t.rid
                  FROM (  SELECT LG1.ROWID rid
                            FROM RC_MESSAGE_LOG LG1
                                INNER JOIN RC_SEND_MESSAGE_LOG SG
                                ON LG1.MESSAGE_SEND_LOG = SG.MESSAGE_SEND_LOG
                           where LG1.STEP IN ('1', '2')
                            AND LG1.COMUPTE_DATE >= 20171225
                            AND LG1.COMUPTE_DATE <= 20180201
                        ORDER BY LG1.MESSAGE_ID DESC) t
                 WHERE ROWNUM <= 31570)
         WHERE rn > 31560) t2
 WHERE LG.ROWID = t2.rid        
   and 1 = 1
   order by LG.MESSAGE_ID desc