关于sql_profile中的绑定变量(r4笔记第57天)

使用sql_profile来调优一些紧急的性能sql可以起到立竿见影的效果，如果sql语句本身结构就很清晰，简单，略作修改就能得到调优后的sql语句。但是如果语句中含有绑定变量，如果要得到调优后的sql_id就有些困难了。比如我们存在下面的sql语句。

SELECT NVL(SUM(CUST.WEIGHT), 0) TOTAL_WEIGHT
  FROM BL1_CUSTOMER CUST, BL1_CYCLE_CUSTOMERS CYC_CUST
 WHERE CYC_CUST.PERIOD_KEY = :periodKey
   AND CYC_CUST.CYCLE_SEQ_NO = :cycleSeqNo
   AND CYC_CUST.CUSTOMER_NO = CUST.CUSTOMER_ID
   AND (CYC_CUST.UNDO_REQ_TYPE = 'N' OR CYC_CUST.UNDO_REQ_TYPE IS NULL)
   AND EXISTS
 (SELECT 1
          FROM BL1_CYC_PAYER_POP PAYER, BL1_DOCUMENT DOC
         WHERE PAYER.PERIOD_KEY = :periodKey
           AND PAYER.CYCLE_SEQ_NO = :cycleSeqNo
           AND PAYER.CYCLE_SEQ_RUN = :cycleSeqRun
           AND PAYER.CUSTOMER_NO = CYC_CUST.CUSTOMER_NO
           AND PAYER.DB_STATUS = 'BL'
           AND (PAYER.UNDO_REQ_TYPE = 'N' OR PAYER.UNDO_REQ_TYPE IS NULL)
           AND PAYER.FORMAT_EXT_DATE IS NULL
           AND DOC.PERIOD_KEY = :periodKey
           AND DOC.CYCLE_SEQ_NO = :cycleSeqNo
           AND DOC.CYCLE_SEQ_RUN = :cycleSeqRun
           AND PAYER.BA_NO = DOC.BA_NO
           AND doc.DOC_PRODUCE_IND IN ('Y', 'E'))

需要添加一个hint 得到一个新的sql_id.

SELECT NVL(SUM(CUST.WEIGHT), 0) TOTAL_WEIGHT
  FROM BL1_CUSTOMER CUST, BL1_CYCLE_CUSTOMERS CYC_CUST
 WHERE CYC_CUST.PERIOD_KEY = :periodKey
   AND CYC_CUST.CYCLE_SEQ_NO = :cycleSeqNo
   AND CYC_CUST.CUSTOMER_NO = CUST.CUSTOMER_ID
   AND (CYC_CUST.UNDO_REQ_TYPE = 'N' OR CYC_CUST.UNDO_REQ_TYPE IS NULL)
   AND EXISTS
 (SELECT /*+ unnest parallel(payer,4) full(payer)*/1
          FROM BL1_CYC_PAYER_POP PAYER, BL1_DOCUMENT DOC
         WHERE PAYER.PERIOD_KEY = :periodKey
           AND PAYER.CYCLE_SEQ_NO = :cycleSeqNo
           AND PAYER.CYCLE_SEQ_RUN = :cycleSeqRun
           AND PAYER.CUSTOMER_NO = CYC_CUST.CUSTOMER_NO
           AND PAYER.DB_STATUS = 'BL'
           AND (PAYER.UNDO_REQ_TYPE = 'N' OR PAYER.UNDO_REQ_TYPE IS NULL)
           AND PAYER.FORMAT_EXT_DATE IS NULL
           AND DOC.PERIOD_KEY = :periodKey
           AND DOC.CYCLE_SEQ_NO = :cycleSeqNo
           AND DOC.CYCLE_SEQ_RUN = :cycleSeqRun
           AND PAYER.BA_NO = DOC.BA_NO
           AND doc.DOC_PRODUCE_IND IN ('Y', 'E'))

如果使用explain plan可以得到包含绑定变量的执行计划，但是却无法得到对应的sql_id 比如sql_id 为74pzzzjddkyd4


74pzzzjddkyd4 SELECT NVL(SUM(CUST.WEIGHT), 0) TOTAL_WEIGHT FROM   BL1_CUSTOMER CUST        ,BL1_CYCLE_CUSTOMERS CY             
                        ...
              Q_TYPE IS NULL)   AND  EXISTS (SELECT 1                FROM   BL1_CYC_PAYER_POP PAYER
                     ...

使用explain plan for之后可以得到一个执行计划情况，但是sql_id却是不同的。

73d1q5xd835kt explain plan for
              SELECT NVL(SUM(CUST.WEIGHT), 0) TOTAL_WEIGHT
                ...
 AND EXISTS
               (SELECT 1
                ...

对于这种情况，可以使用variable 来实现。存在几个变量，然后手工赋值，执行一下，也可以中途停止，就能够从v$sql里面抓到对应的sql_id variable periodKey number; variable cycleSeqNo number; variable cycleSeqRun number; exec :periodKey:=61; exec :cycleSeqNo:=4106; exec :cycleSeqRun:=0; 然后执行修改后的语句，这样我们就得到了添加了Hint之后的sql语句。如果我们需要修改的sql语句中的变量是:1 :2之类的，比如： select /*+ leading(s) index(s TABLE_BPM_STEP_INST_5IX) use_nl(s p step) */ ... s.WORKER FROM TABLE_BPM_STEP_INST s, TABLE_BPM_STEP step WHERE s.root2proc_inst = :1 AND s.step2step = step.objid AND ( NOT (step.step_type = 4)) AND ( s.assignee = 'BpmInServer' OR s.assignee = 'BpmInServerSmThr' OR s.assignee = 'BpmJms') AND s.committer is NOT NULL AND ( s.status in (50 )) 这样通过variable就会出错了。只使用数字来作为变量还是不合规则的。我们可以尝试使用如下的一个简单pl/sql来实现。比如存在一个变量，我们就在 cursor中定义一个字段，存在多个变量就定义多个字段，最后在execute immediate的后面使用using子句来完成。


declare
cursor temp_cur is select '100' id from dual;
begin
for i in temp_cur loop
execute immediate 'select  /*+ leading(s) index(s TABLE_BPM_STEP_INST_1IX) use_nl(s step) */ 
s.ALLOW_CREATE, s.ASSIGNEE, s.ASYNC_RETURNED_PARAMS,
s.ATTACHER2STEP_INST, s.COMMITTER, s.CONTROL_COUNT,
s.CURR_FAULT2FAULT_INFO, s.DO_AVAIL_ON_RESUM, s.DO_FIN_ON_RESUM,
s.HAS_DEPENDENTS, s.HAS_MARCH_REND, s.HAS_REND, s.INFLOW_BITS,
s.ITER_COUNT, s.NUM_OR_PREREQS, s.NUM_PENDING, s.NUM_PENDING_PREREQS,
s.OBJID, s.OUTFLOW_BITS, s.PARAMS, s.PARENT2PROC_INST,
s.ROOT2PROC_INST, s.START_TIME, s.STATUS, s.STATUS_CHANGE_TIME,
s.STEP2STEP, s.TARGETED_BY_ALARMS, s.TRIGGERS_ALARMS, s.WAIT_TIME,
s.WORKER  FROM TABLE_BPM_STEP_INST s, TABLE_BPM_STEP step WHERE
s.root2proc_inst = :1  AND s.step2step = step.objid AND ( NOT
(step.step_type = 4)) AND ( s.assignee = ''BpmInServer''       OR
s.assignee = ''BpmInServerSmThr''       OR s.assignee = ''BpmJms'') AND
s.committer is NOT NULL AND ( s.status in (50                    ))' using i.id;
end loop;
end;
/

通过v$sql即可得到对应的sql_id 目前自己使用的是这两种方式来解决绑定变量的问题，如果有更好的，希望拍砖。