甲骨文预处理语句挂起

有下一个分区表：甲骨文预处理语句挂起

CREATE TABLE "ERMB_LOG_TEST_BF"."OUT_SMS"(
    "TRX_ID" NUMBER(19,0) NOT NULL ENABLE, 
    "CREATE_TS" TIMESTAMP (3) DEFAULT systimestamp NOT NULL ENABLE, 
    /* other fields... */ 
) PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 
    STORAGE(BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) 
    TABLESPACE "ERMB_LOG_TEST_BF" 
    PARTITION BY RANGE ("TRX_ID") INTERVAL (281474976710656) 
    (PARTITION "SYS_P1358" VALUES LESS THAN (59109745109237760) SEGMENT CREATION IMMEDIATE 
    PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 
    NOCOMPRESS LOGGING 
    STORAGE(INITIAL 8388608 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 
    PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 
    BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) 
    TABLESPACE "ERMB_LOG_TEST_BF"); 

CREATE INDEX "ERMB_LOG_TEST_BF"."OUT_SMS_CREATE_TS_TRX_ID_IX" ON "ERMB_LOG_TEST_BF"."OUT_SMS" ("CREATE_TS" DESC, "TRX_ID" DESC) 
    PCTFREE 10 INITRANS 2 MAXTRANS 255 
    STORAGE(
    BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) LOCAL 
    (PARTITION "SYS_P1358" 
    PCTFREE 10 INITRANS 2 MAXTRANS 255 LOGGING 
    STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 
    PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 
    BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT) 
    TABLESPACE "ERMB_LOG_TEST_BF");

我有SQL查询，其中选择20条记录按日期和交易下令：

select rd from (
    select /*+ INDEX(OUT_SMS OUT_SMS_CREATE_TS_TRX_ID_IX) */ rowid rd 
    from OUT_SMS  
    where TRX_ID between 34621422135410688 and 72339069014638591  
     and CREATE_TS between to_timestamp('2013-02-01 00:00:00', 'yyyy-mm-dd hh24:mi:ss') 
         and to_timestamp('2013-03-06 08:57:00', 'yyyy-mm-dd hh24:mi:ss')  
    order by CREATE_TS DESC, TRX_ID DESC 
) where rownum <= 20

甲骨文产生了下一步的计划：

----------------------------------------------------------------------------------------------------------------------------------- 
    | Id | Operation     | Name      | Rows | Bytes |TempSpc| Cost (%CPU)| Time  | Pstart| Pstop | 
    ----------------------------------------------------------------------------------------------------------------------------------- 
    | 0 | SELECT STATEMENT   |        | 20 | 240 |  | 4788K (1)| 00:05:02 |  |  | 
    |* 1 | COUNT STOPKEY    |        |  |  |  |   |   |  |  | 
    | 2 | VIEW      |        | 312M| 3576M|  | 4788K (1)| 00:05:02 |  |  | 
    |* 3 | SORT ORDER BY STOPKEY |        | 312M|  9G| 12G| 4788K (1)| 00:05:02 |  |  | 
    | 4 |  PARTITION RANGE ITERATOR|        | 312M|  9G|  | 19 (0)| 00:00:01 |  1 | 48 | 
    |* 5 |  COUNT STOPKEY   |        |  |  |  |   |   |  |  | 
    |* 6 |  INDEX RANGE SCAN  | OUT_SMS_CREATE_TS_TRX_ID_IX | 312M|  9G|  | 19 (0)| 00:00:01 |  1 | 48 | 
    ----------------------------------------------------------------------------------------------------------------------------------- 

    Predicate Information (identified by operation id): 
    --------------------------------------------------- 

    1 - filter(ROWNUM<=20) 
    3 - filter(ROWNUM<=20) 
    5 - filter(ROWNUM<=20) 
    6 - access(SYS_OP_DESCEND("CREATE_TS")>=HEXTORAW('878EFCF9F6C5FEFAFF') AND 
    SYS_OP_DESCEND("TRX_ID")>=HEXTORAW('36F7E7D7F8A4F0BFA9A3FF') AND 
    SYS_OP_DESCEND("CREATE_TS")<=HEXTORAW('878EFDFEF8FEF8FF') AND 
    SYS_OP_DESCEND("TRX_ID")<=HEXTORAW('36FBD0E9D4E9DBD5F8A6FF')) 
    filter(SYS_OP_UNDESCEND(SYS_OP_DESCEND("CREATE_TS"))<=TIMESTAMP' 2013-03-06 08:57:00,000000000' AND 
    SYS_OP_UNDESCEND(SYS_OP_DESCEND("TRX_ID"))<=72339069014638591 AND 
    SYS_OP_UNDESCEND(SYS_OP_DESCEND("TRX_ID"))>=34621422135410688 AND 
    SYS_OP_UNDESCEND(SYS_OP_DESCEND("CREATE_TS"))>=TIMESTAMP' 2013-02-01 00:00:00,000000000')

它完美地工作。

顺便说一句，表OUT_SMS是通过TRX_ID字段分配和OUT_SMS_CREATE_TS_TRX_ID_IX是在每个分区上本地索引(CREATE_TS DESC, TRX_ID DESC)。

但如果我这个查询转换为准备好的语句：

select rd from (
    select /*+ INDEX(OUT_SMS OUT_SMS_CREATE_TS_TRX_ID_IX) */ rowid rd 
    from OUT_SMS  
    where TRX_ID between ? and ?  
     and CREATE_TS between ? and ? 
    order by CREATE_TS DESC, TRX_ID DESC 
) where rownum <= 20

甲骨文产生的下一个计划：

---------------------------------------------------------------------------------------------------------------------------- 
    | Id | Operation     | Name      | Rows | Bytes | Cost (%CPU)| Time  | Pstart| Pstop | 
    ---------------------------------------------------------------------------------------------------------------------------- 
    | 0 | SELECT STATEMENT    |        | 20 | 240 | 14743 (1)| 00:00:01 |  |  | 
    |* 1 | COUNT STOPKEY    |        |  |  |   |   |  |  | 
    | 2 | VIEW      |        | 1964 | 23568 | 14743 (1)| 00:00:01 |  |  | 
    |* 3 | SORT ORDER BY STOPKEY  |        | 1964 | 66776 | 14743 (1)| 00:00:01 |  |  | 
    |* 4 |  FILTER     |        |  |  |   |   |  |  | 
    | 5 |  PARTITION RANGE ITERATOR|        | 1964 | 66776 | 14742 (1)| 00:00:01 | KEY | KEY | 
    |* 6 |  INDEX RANGE SCAN  | OUT_SMS_CREATE_TS_TRX_ID_IX | 1964 | 66776 | 14742 (1)| 00:00:01 | KEY | KEY | 
    ---------------------------------------------------------------------------------------------------------------------------- 

    Predicate Information (identified by operation id): 
    --------------------------------------------------- 

    1 - filter(ROWNUM<=20) 
    3 - filter(ROWNUM<=20) 
    4 - filter(TO_TIMESTAMP(:RR,'yyyy-mm-dd hh24:mi:ss')<=TO_TIMESTAMP(:T,'yyyy-mm-dd hh24:mi:ss') AND 
    TO_NUMBER(:ABC)<=TO_NUMBER(:EBC)) 
    6 - access(SYS_OP_DESCEND("CREATE_TS")>=SYS_OP_DESCEND(TO_TIMESTAMP(:T,'yyyy-mm-dd hh24:mi:ss')) AND 
    SYS_OP_DESCEND("TRX_ID")>=SYS_OP_DESCEND(TO_NUMBER(:EBC)) AND 
    SYS_OP_DESCEND("CREATE_TS")<=SYS_OP_DESCEND(TO_TIMESTAMP(:RR,'yyyy-mm-dd hh24:mi:ss')) AND 
    SYS_OP_DESCEND("TRX_ID")<=SYS_OP_DESCEND(TO_NUMBER(:ABC))) 
    filter(SYS_OP_UNDESCEND(SYS_OP_DESCEND("TRX_ID"))>=TO_NUMBER(:ABC) AND 
    SYS_OP_UNDESCEND(SYS_OP_DESCEND("TRX_ID"))<=TO_NUMBER(:EBC) AND 
    SYS_OP_UNDESCEND(SYS_OP_DESCEND("CREATE_TS"))>=TO_TIMESTAMP(:RR,'yyyy-mm-dd hh24:mi:ss') AND 
    SYS_OP_UNDESCEND(SYS_OP_DESCEND("CREATE_TS"))<=TO_TIMESTAMP(:T,'yyyy-mm-dd hh24:mi:ss'))

操作COUNT STOPKEY从计划中消失。此操作应在分析索引后从每个分区获取20行（如第一个查询）之后进行。

如何编写准备好的语句以在计划中使用COUNT STOPKEY？

来源

2013-03-12 Tsimon D

什么是准备好的语句和'？'在'之间？和？' ？只能给你一个有关日期的建议。要比较日期，请使用trunc（）删除时间部分，除非您确实需要与秒进行比较。使用row_number（）而不是rownum。 – Art 2013-03-12 12:52:17

这里涉及什么类型的分区？最好显示表格和索引DDL。另外，请使用DBMS_Xplan获取执行计划并将其粘贴到问题中，而不是链接到图像。 – 2013-03-15 10:59:03

“查询是否只检索单个分区中的行？” - 不，我必须从几个分区获取数据。 – 2013-03-15 12:16:32

动态SQL是一个选项吗？这样你就可以“注入”TRX_ID和CREATE_TS过滤器的值，而不需要使用绑定变量。也许那么生成的计划将包括COUNT STOPKEY。

动态SQL我的意思是让你动态地构造SQL，然后用EXECUTE IMMEDIATE或OPEN调用它。通过使用这个，你可以直接使用你的过滤器而无需绑定变量。例如：

v_sql VARCHAR2(1000) := 
    'select rd from (
     select /*+ INDEX(OUT_SMS OUT_SMS_CREATE_TS_TRX_ID_IX) */ rowid rd 
     from OUT_SMS  
     where TRX_ID between ' || v_trx_id_min || ' and ' || v_trx_id_maxb || '  
      and CREATE_TS between ' || v_create_ts_min|| ' and ' || v_create_ts_max || ' 
     order by CREATE_TS DESC, TRX_ID DESC 
    ) where rownum <= 20';

然后使用调用它：

EXECUTE IMMEDIATE v_sql;

甚至：

OPEN cursor_out FOR v_sql;

来源

2013-03-18 16:43:11

模拟绑定变量对于性能没有意义。对不起，我不明白你的问题。 – 2013-03-19 17:15:02

请参阅编辑答案。这个想法不是使用绑定变量。你如何分析表格？ – 2013-03-19 17:40:02

当您使用绑定变量，甲骨文被迫使用dynamic partition pruning而不是static partition pruning。这样做的结果是，Oracle在分析时不知道哪些分区将被访问，因为这会根据您的输入变量而改变。

这意味着当使用文字值（而不是绑定变量）时，我们知道哪些分区将被本地索引访问。因此，在删除分区之前，可以将count stopkey应用于索引的输出。

当使用绑定变量时，partition range iterator必须找出您正在访问的分区。然后进行检查，以确保两个操作之间的第一个变量实际上具有较低的值，然后是第二个（第二个计划中的filter操作）。

这可以很容易地再现，如下面的测试情况表明：

create table tab (
    x date, 
    y integer, 
    filler varchar2(100) 
) partition by range(x) (
    partition p1 values less than (date'2013-01-01'), 
    partition p2 values less than (date'2013-02-01'), 
    partition p3 values less than (date'2013-03-01'), 
    partition p4 values less than (date'2013-04-01'), 
    partition p5 values less than (date'2013-05-01'), 
    partition p6 values less than (date'2013-06-01') 
); 


insert into tab (x, y) 
    select add_months(trunc(sysdate, 'y'), mod(rownum, 5)), rownum, dbms_random.string('x', 50) 
    from dual 
    connect by level <= 1000; 

create index i on tab(x desc, y desc) local; 

exec dbms_stats.gather_table_stats(user, 'tab', cascade => true); 

explain plan for 
SELECT * FROM (
    SELECT rowid FROM tab 
    where x between date'2013-01-01' and date'2013-02-02' 
    and y between 50 and 100 
    order by x desc, y desc 
) 
where rownum <= 5; 

SELECT * FROM table(dbms_xplan.display(null, null, 'BASIC +ROWS +PARTITION')); 

--------------------------------------------------------------------                                                           
| Id | Operation     | Name | Rows | Pstart| Pstop |                                                           
--------------------------------------------------------------------                                                           
| 0 | SELECT STATEMENT   |  |  1 |  |  |                                                           
| 1 | COUNT STOPKEY    |  |  |  |  |                                                           
| 2 | VIEW      |  |  1 |  |  |                                                           
| 3 | SORT ORDER BY STOPKEY |  |  1 |  |  |                                                           
| 4 |  PARTITION RANGE ITERATOR|  |  1 |  2 |  3 |                                                           
| 5 |  COUNT STOPKEY   |  |  |  |  |                                                           
| 6 |  INDEX RANGE SCAN  | I |  1 |  2 |  3 |                                                           
-------------------------------------------------------------------- 

explain plan for 
SELECT * FROM (
    SELECT rowid FROM tab 
    where x between to_date(:st, 'dd/mm/yyyy') and to_date(:en, 'dd/mm/yyyy') 
    and y between :a and :b 
    order by x desc, y desc 
) 
where rownum <= 5; 

SELECT * FROM table(dbms_xplan.display(null, null, 'BASIC +ROWS +PARTITION')); 

---------------------------------------------------------------------                                                           
| Id | Operation     | Name | Rows | Pstart| Pstop |                                                           
---------------------------------------------------------------------                                                           
| 0 | SELECT STATEMENT    |  |  1 |  |  |                                                           
| 1 | COUNT STOPKEY    |  |  |  |  |                                                           
| 2 | VIEW      |  |  1 |  |  |                                                           
| 3 | SORT ORDER BY STOPKEY  |  |  1 |  |  |                                                           
| 4 |  FILTER     |  |  |  |  |                                                           
| 5 |  PARTITION RANGE ITERATOR|  |  1 | KEY | KEY |                                                           
| 6 |  INDEX RANGE SCAN  | I |  1 | KEY | KEY |                                                           
---------------------------------------------------------------------

如在示例中，第二查询只能在分析时过滤分区到key，而不是精确的分区作为在第一个例子中。

这是少数情况下文字值可以提供比绑定变量更好的性能之一。你应该调查这对你是否有可能。

最后，你说你想从每个分区20行。您的查询不会做到这一点，它会根据您的订购返回前20行。对于20行/分区，你需要做的是这样的：

select rd from (
    select rowid rd, 
      row_number() over (partition by trx_id order by create_ts desc) rn 
    from OUT_SMS  
    where TRX_ID between ? and ?  
     and CREATE_TS between ? and ? 
    order by CREATE_TS DESC, TRX_ID DESC 
) where rn <= 20

UPDATE

你没有得到的count stopkey的原因是与filter运做中的4号线“坏“计划。如果重复上述示例，但没有分区，则可以更清楚地看到这一点。

这给你如下图：

----------------------------------------                                                                  
| Id | Operation    | Name |                                                                  
----------------------------------------                                                                  
| 0 | SELECT STATEMENT  |  |                                                                  
|* 1 | COUNT STOPKEY   |  |                                                                  
| 2 | VIEW     |  |                                                                  
|* 3 | SORT ORDER BY STOPKEY|  |                                                                  
|* 4 |  TABLE ACCESS FULL | TAB |                                                                  
----------------------------------------                                                                  

Predicate Information (identified by operation id):                                                               
---------------------------------------------------                                                               

    1 - filter(ROWNUM<=5)                                                                      
    3 - filter(ROWNUM<=5)                                                                      
    4 - filter("X">=TO_DATE(' 2013-01-01 00:00:00', 'syyyy-mm-dd                                                            
       hh24:mi:ss') AND "X"<=TO_DATE(' 2013-02-02 00:00:00', 'syyyy-mm-dd                                                        
       hh24:mi:ss') AND "Y">=50 AND "Y"<=100)                                                                                                                                  

----------------------------------------                                                                  
| Id | Operation    | Name |                                                                  
----------------------------------------                                                                  
| 0 | SELECT STATEMENT  |  |                                                                  
|* 1 | COUNT STOPKEY   |  |                                                                  
| 2 | VIEW     |  |                                                                  
|* 3 | SORT ORDER BY STOPKEY|  |                                                                  
|* 4 |  FILTER    |  |                                                                  
|* 5 |  TABLE ACCESS FULL | TAB |                                                                  
----------------------------------------                                                                  

Predicate Information (identified by operation id):                                                               
---------------------------------------------------                                                               

    1 - filter(ROWNUM<=5)                                                                      
    3 - filter(ROWNUM<=5)                                                                      
    4 - filter(TO_NUMBER(:A)<=TO_NUMBER(:B) AND                                                                
       TO_DATE(:ST,'dd/mm/yyyy')<=TO_DATE(:EN,'dd/mm/yyyy'))                                                           
    5 - filter("Y">=TO_NUMBER(:A) AND "Y"<=TO_NUMBER(:B) AND                                                             
       "X">=TO_DATE(:ST,'dd/mm/yyyy') AND "X"<=TO_DATE(:EN,'dd/mm/yyyy'))

正如你可以看到，有一个额外的filter操作时使用sort order by stopkey出庭绑定变量。访问索引后会发生这种情况。这将检查变量的值是否允许返回数据（第一个变量实际上具有比第二个变量更小的值）。当使用文字时，这是不必要的，因为优化器已经知道50小于100（在这种情况下）。它不知道：a是否小于：b在解析时间。

为什么这是我不知道的。这可能是由Oracle有意设计的 - 如果为变量设置的值导致零行 - 或仅仅是疏忽，做停机检查没有意义。

来源

2013-03-18 17:48:41

区别在于，在第一种情况下，COUNT STOPKEY在**分区范围索引扫描内部被推**，这意味着Oracle足够聪明地认识到为了总共获得20行，它不需要超过每个分区20行。使用绑定变量时，这种微妙之处会丢失。我不明白为什么动态分区修剪无法增强以在每个分区扫描中推送rownum谓词。你并没有真正给出这种行为的有效理由，也没有一个好的解决方法=） – 2013-03-19 09:31:03

@VincentMalgrat - 嗯，我认为“不使用绑定变量”是一种解决方法，尽管不一定合意！如果查询不经常执行和/或在'trx_id'的过滤器中使用的值有限，那么额外的解析开销应该是最小的，这使得这是一种可能的方法。 – 2013-03-20 11:38:42

我同意你的解决方法，不幸的是OP似乎想要使用绑定变量。我不同意你的解释，虽然=）“FILTER”不能代替“COUNT STOPKEY”，因为它们是根本不同的操作。正如你所解释的，“FILTER”允许Oracle分支出不可能的操作。 COUNT STOPKEY是一种优化，Oracle允许每个分区仅提取20行，因为它总共需要20行。当使用绑定变量时，这种优化不存在，这可能是一个错误（请参阅相关的metalink错误12873183和8500130）。 – 2013-03-20 13:16:33

我可以在11.2.0.3上重现您的发现。这里是我的测试案例：

SQL> -- Table with 100 partitions of 100 rows 
SQL> CREATE TABLE out_sms 
    2 PARTITION BY RANGE (trx_id) 
    3  INTERVAL (100) (PARTITION p0 VALUES LESS THAN (0)) 
    4 AS 
    5 SELECT ROWNUM trx_id, 
    6   trunc(SYSDATE) + MOD(ROWNUM, 50) create_ts 
    7 FROM dual CONNECT BY LEVEL <= 10000; 

Table created 

SQL> CREATE INDEX OUT_SMS_IDX ON out_sms (create_ts desc, trx_id desc) LOCAL; 

Index created 

[static plan] 

SELECT rd 
    FROM (SELECT /*+ INDEX(OUT_SMS OUT_SMS_IDX) */ 
     rowid rd 
      FROM out_sms 
     WHERE create_ts BETWEEN systimestamp AND systimestamp + 10 
      AND trx_id BETWEEN 1 AND 500 
     ORDER BY create_ts DESC, trx_id DESC) 
WHERE rownum <= 20;  
--------------------------------------------------------------------------- 
| Id | Operation     | Name  | Rows | Pstart| Pstop | 
--------------------------------------------------------------------------- 
| 0 | SELECT STATEMENT   |    |  1 |  |  | 
|* 1 | COUNT STOPKEY    |    |  |  |  | 
| 2 | VIEW      |    |  1 |  |  | 
|* 3 | SORT ORDER BY STOPKEY |    |  1 |  |  | 
| 4 |  PARTITION RANGE ITERATOR|    |  1 |  2 |  7 | 
|* 5 |  COUNT STOPKEY   |    |  |  |  | 
|* 6 |  INDEX RANGE SCAN  | OUT_SMS_IDX |  1 |  2 |  7 | 
--------------------------------------------------------------------------- 

[dynamic]  
---------------------------------------------------------------------------- 
| Id | Operation     | Name  | Rows | Pstart| Pstop | 
---------------------------------------------------------------------------- 
| 0 | SELECT STATEMENT    |    |  1 |  |  | 
|* 1 | COUNT STOPKEY    |    |  |  |  | 
| 2 | VIEW      |    |  1 |  |  | 
|* 3 | SORT ORDER BY STOPKEY  |    |  1 |  |  | 
|* 4 |  FILTER     |    |  |  |  | 
| 5 |  PARTITION RANGE ITERATOR|    |  1 | KEY | KEY | 
|* 6 |  INDEX RANGE SCAN  | OUT_SMS_IDX |  1 | KEY | KEY | 
----------------------------------------------------------------------------

如您的示例ROWNUM谓语推内分区索引范围扫描在第一种情况下，不会在第二种情况下。当使用静态变量时，计划显示Oracle每个分区仅提取20行，而使用动态变量时，Oracle将提取所有行，以满足每个分区中的WHERE子句。我找不到可以在使用绑定变量时推送谓词的设置或统计配置。

我希望你可以使用动态过滤器与更广泛的静态极限赛制，但似乎ROWNUM谓词不是单个分区里面，只要不存在动态变量使用：

SELECT rd 
    FROM (SELECT /*+ INDEX(OUT_SMS OUT_SMS_IDX) */ 
     rowid rd 
      FROM out_sms 
     WHERE nvl(create_ts+:5, sysdate) BETWEEN :1 AND :2 
      AND nvl(trx_id+:6, 0) BETWEEN :3 AND :4 
      AND trx_id BETWEEN 1 AND 500 
      AND create_ts BETWEEN systimestamp AND systimestamp + 10 
     ORDER BY create_ts DESC, trx_id DESC) 
WHERE rownum <= 20 

Plan hash value: 2740263591 

---------------------------------------------------------------------------- 
| Id | Operation     | Name  | Rows | Pstart| Pstop | 
---------------------------------------------------------------------------- 
| 0 | SELECT STATEMENT    |    |  1 |  |  | 
|* 1 | COUNT STOPKEY    |    |  |  |  | 
| 2 | VIEW      |    |  1 |  |  | 
|* 3 | SORT ORDER BY STOPKEY  |    |  1 |  |  | 
|* 4 |  FILTER     |    |  |  |  | 
| 5 |  PARTITION RANGE ITERATOR|    |  1 |  2 |  7 | 
|* 6 |  INDEX RANGE SCAN  | OUT_SMS_IDX |  1 |  2 |  7 | 
----------------------------------------------------------------------------

如果此查询很重要并且其性能至关重要，则可以将该索引转换为全局索引。它会增加分区维护，但大多数分区操作可以在最新的Oracle版本中在线使用。在这种情况下，全局索引将与标准非分区表一样工作：

SQL> drop index out_sms_idx; 

Index dropped 

SQL> CREATE INDEX OUT_SMS_IDX ON out_sms (create_ts DESC, trx_id desc); 

Index created 

SELECT rd 
    FROM (SELECT 
     rowid rd 
      FROM out_sms 
     WHERE create_ts BETWEEN :1 AND :2 
      AND trx_id BETWEEN :3 AND :4 
     ORDER BY create_ts DESC, trx_id DESC) 
WHERE rownum <= 20 

------------------------------------------------------------------------ 
| Id | Operation   | Name  | Rows | Bytes | Cost (%CPU)| 
------------------------------------------------------------------------ 
| 0 | SELECT STATEMENT |    |  1 | 12 |  2 (0)| 
|* 1 | COUNT STOPKEY  |    |  |  |   | 
| 2 | VIEW    |    |  1 | 12 |  2 (0)| 
|* 3 | FILTER   |    |  |  |   | 
|* 4 |  INDEX RANGE SCAN| OUT_SMS_IDX |  1 | 34 |  2 (0)| 
------------------------------------------------------------------------

来源

2013-03-19 10:27:17

我对全局索引有了一些了解，但行数可能非常大，我将失去分区优势。 – 2013-03-19 17:08:10

甲骨文预处理语句挂起

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