Oracle SQL 消耗大量临时空间答案

【问题标题】：Oracle SQL consumes huge temp spaceOracle SQL 消耗大量临时空间
【发布时间】：2014-03-03 06:49:56
【问题描述】：

我面临临时空间和查询性能之间的权衡问题。

我的场景是这样的：我有一个巨大的事务表（跨越 25 个分区的 200 亿条记录）和一个包含 7 条记录的小型指标查找表。我需要处理每个指标记录的每个事务记录。基本上输出将是 7 * 200 亿条记录。此输出必须基于 5-6 列进行聚合。

我考虑了两种选择：

交叉连接这两个表并使用“case when”指定处理逻辑wrt metric并进行“group by”操作。
对每个指标 id 有 7 个不同的查询，结果是“UNION ALL”。

#1 消耗了大约 250 GB 的巨大临时空间，而#2 运行了大约 230 分钟。

有没有办法，我可以优化这些选项之一？我需要在 60 分钟内完成此查询。

添加查询

@david 查询粘贴在下面

WITH IDQ_LKP AS 
    (SELECT '703' AS METRIC_ID,'desc1' AS EN_METRIC_1_NM
    FROM DUAL
    UNION ALL
    SELECT '702' AS METRIC_ID,'desc1' AS EN_METRIC_1_NM
    FROM DUAL
    UNION ALL
    SELECT '704' AS METRIC_ID,'% desc1' AS EN_METRIC_1_NM
    FROM DUAL
    UNION ALL 
    SELECT '705' AS METRIC_ID,'desc2' AS EN_METRIC_1_NM
    FROM DUAL
    UNION ALL 
    SELECT '706' AS METRIC_ID,'desc3' AS EN_METRIC_1_NM
    FROM DUAL
    UNION ALL
    SELECT '707' AS METRIC_ID,'desc5' AS EN_METRIC_1_NM
    FROM DUAL
    UNION ALL
    SELECT '701' AS METRIC_ID,'desc4' AS EN_METRIC_1_NM
    FROM DUAL)
SELECT /*+ parallel(16) USE_HASH_AGGREGATION */ col1 ,
         col2 ,
         'Monthly Snapshots' AS Time_Rollup , col3 , date_pk , colr , col5 , colr_DESC , col5_DESC , metric_id , EN_METRIC_1_NM , sum (
    CASE
    WHEN (metric_id='704'
        AND record_identifier=17 )
        OR (metric_id='705'
        AND record_identifier=123)
        OR (metric_id='706'
        AND record_identifier=43)
        OR (metric_id='707'
        AND record_identifier=34) THEN
    nvl ( record_count,0 )
    WHEN metric_id NOT IN ('704','705','706','707') THEN
    NULL
    ELSE 0
    END ) AS METRIC_1_CY , NULL AS METRIC_1_LY , sum (
    CASE
    WHEN (metric_id='703'
        AND record_identifier=17)
        OR (metric_id='705'
        AND record_identifier=777 )
        OR (metric_id='702'
        AND record_identifier=123 )
        OR (metric_id='704'
        AND record_identifier=17 )
        OR (metric_id='706'
        AND record_identifier=99999997 )
        OR (metric_id='707'
        AND record_identifier=99999996) THEN
    nvl ( record_count,0 )
    WHEN metric_id NOT IN ('702','703','704','705','706','707') THEN
    NULL
    ELSE 0
    END ) AS METRIC_2_CY , NULL AS METRIC_2_LY , NULL AS METRIC_3_CY , NULL AS METRIC_3_LY
FROM TXN,LKP
WHERE col1=2
GROUP BY  col1 , col2 , col3 , date_pk , colr , col5 , colr_DESC , col5_DESC, metric_id , EN_METRIC_1_NM

你好，

我仍然在解释计划中看到需要 252 GB 的临时空间...

-------------------------------------------------------------------------------------------------------------------------------------------------
| Id  | Operation                      | Name                      | Rows  | Bytes |TempSpc| Cost  | Pstart| Pstop |    TQ  |IN-OUT| PQ Distrib |
-------------------------------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT               |                           |       |       |       |    17M|       |       |        |      |            |
|   1 |  PX COORDINATOR                |                           |       |       |       |       |       |       |        |      |            |
|   2 |   PX SEND QC (RANDOM)          | :TQ10003                  |  1894M|   217G|       |    17M|       |       |  Q1,03 | P->S | QC (RAND)  |
|   3 |    HASH GROUP BY               |                           |  1894M|   217G|   262G|    17M|       |       |  Q1,03 | PCWP |            |
|   4 |     PX RECEIVE                 |                           |  1894M|   217G|       |    17M|       |       |  Q1,03 | PCWP |            |
|   5 |      PX SEND HASH              | :TQ10002                  |  1894M|   217G|       |    17M|       |       |  Q1,02 | P->P | HASH       |
|   6 |       HASH GROUP BY            |                           |  1894M|   217G|   262G|    17M|       |       |  Q1,02 | PCWP |            |
|   7 |        MERGE JOIN CARTESIAN    |                           |  1894M|   217G|       |   149K|       |       |  Q1,02 | PCWP |            |
|   8 |         BUFFER SORT            |                           |       |       |       |       |       |       |  Q1,02 | PCWC |            |
|   9 |          PX RECEIVE            |                           |     7 |   154 |       |    14 |       |       |  Q1,02 | PCWP |            |
|  10 |           PX SEND BROADCAST    | :TQ10000                  |     7 |   154 |       |    14 |       |       |        | S->P | BROADCAST  |
|  11 |            VIEW                |                           |     7 |   154 |       |    14 |       |       |        |      |            |
|  12 |             UNION-ALL          |                           |       |       |       |       |       |       |        |      |            |
|  13 |              FAST DUAL         |                           |     1 |       |       |     2 |       |       |        |      |            |
|  14 |              FAST DUAL         |                           |     1 |       |       |     2 |       |       |        |      |            |
|  15 |              FAST DUAL         |                           |     1 |       |       |     2 |       |       |        |      |            |
|  16 |              FAST DUAL         |                           |     1 |       |       |     2 |       |       |        |      |            |
|  17 |              FAST DUAL         |                           |     1 |       |       |     2 |       |       |        |      |            |
|  18 |              FAST DUAL         |                           |     1 |       |       |     2 |       |       |        |      |            |
|  19 |              FAST DUAL         |                           |     1 |       |       |     2 |       |       |        |      |            |
|  20 |         BUFFER SORT            |                           |   270M|    25G|       |    17M|       |       |  Q1,02 | PCWP |            |
|  21 |          VIEW                  |                           |   270M|    25G|       |       |       |       |  Q1,02 | PCWP |            |
|  22 |           HASH GROUP BY        |                           |   270M|    22G|    29G|   115K|       |       |  Q1,02 | PCWP |            |
|  23 |            PX RECEIVE          |                           |   270M|    22G|       |   843 |       |       |  Q1,02 | PCWP |            |
|  24 |             PX SEND HASH       | :TQ10001                  |   270M|    22G|       |   843 |       |       |  Q1,01 | P->P | HASH       |
|  25 |              PX BLOCK ITERATOR |                           |   270M|    22G|       |   843 |    28 |    55 |  Q1,01 | PCWC |            |
|* 26 |               TABLE ACCESS FULL| TXN                       |   270M|    22G|       |   843 |    28 |    55 |  Q1,01 | PCWP |            |
---------------------------------------------------------------------------------------------------------

它现在正在运行......我怀疑它可能会陷入同样的问题......

计划“UNION ALL”方法..

-------------------------------------------------------------------------------------------------------------------------------------------
| Id  | Operation                | Name                      | Rows  | Bytes |TempSpc| Cost  | Pstart| Pstop |    TQ  |IN-OUT| PQ Distrib |
-------------------------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT         |                           |       |       |       |   774K|       |       |        |      |            |
|   1 |  UNION-ALL               |                           |       |       |       |       |       |       |        |      |            |
|   2 |   PX COORDINATOR         |                           |       |       |       |       |       |       |        |      |            |
|   3 |    PX SEND QC (RANDOM)   | :TQ10001                  |   270M|    18G|       |   100K|       |       |  Q1,01 | P->S | QC (RAND)  |
|   4 |     HASH GROUP BY        |                           |   270M|    18G|    24G|   100K|       |       |  Q1,01 | PCWP |            |
|   5 |      PX RECEIVE          |                           |   270M|    18G|       |   843 |       |       |  Q1,01 | PCWP |            |
|   6 |       PX SEND HASH       | :TQ10000                  |   270M|    18G|       |   843 |       |       |  Q1,00 | P->P | HASH       |
|   7 |        PX BLOCK ITERATOR |                           |   270M|    18G|       |   843 |    28 |    55 |  Q1,00 | PCWC |            |
|*  8 |         TABLE ACCESS FULL| TXN                       |   270M|    18G|       |   843 |    28 |    55 |  Q1,00 | PCWP |            |
|   9 |   PX COORDINATOR         |                           |       |       |       |       |       |       |        |      |            |
|  10 |    PX SEND QC (RANDOM)   | :TQ20001                  |   270M|    21G|       |   112K|       |       |  Q2,01 | P->S | QC (RAND)  |
|  11 |     HASH GROUP BY        |                           |   270M|    21G|    28G|   112K|       |       |  Q2,01 | PCWP |            |
|  12 |      PX RECEIVE          |                           |   270M|    21G|       |   843 |       |       |  Q2,01 | PCWP |            |
|  13 |       PX SEND HASH       | :TQ20000                  |   270M|    21G|       |   843 |       |       |  Q2,00 | P->P | HASH       |
|  14 |        PX BLOCK ITERATOR |                           |   270M|    21G|       |   843 |    28 |    55 |  Q2,00 | PCWC |            |
|* 15 |         TABLE ACCESS FULL| TXN                       |   270M|    21G|       |   843 |    28 |    55 |  Q2,00 | PCWP |            |
|  16 |   PX COORDINATOR         |                           |       |       |       |       |       |       |        |      |            |
|  17 |    PX SEND QC (RANDOM)   | :TQ30001                  |   270M|    21G|       |   112K|       |       |  Q3,01 | P->S | QC (RAND)  |
|  18 |     HASH GROUP BY        |                           |   270M|    21G|    28G|   112K|       |       |  Q3,01 | PCWP |            |
|  19 |      PX RECEIVE          |                           |   270M|    21G|       |   843 |       |       |  Q3,01 | PCWP |            |
|  20 |       PX SEND HASH       | :TQ30000                  |   270M|    21G|       |   843 |       |       |  Q3,00 | P->P | HASH       |
|  21 |        PX BLOCK ITERATOR |                           |   270M|    21G|       |   843 |    28 |    55 |  Q3,00 | PCWC |            |
|* 22 |         TABLE ACCESS FULL| TXN                       |   270M|    21G|       |   843 |    28 |    55 |  Q3,00 | PCWP |            |
|  23 |   PX COORDINATOR         |                           |       |       |       |       |       |       |        |      |            |
|  24 |    PX SEND QC (RANDOM)   | :TQ40001                  |   270M|    21G|       |   112K|       |       |  Q4,01 | P->S | QC (RAND)  |
|  25 |     HASH GROUP BY        |                           |   270M|    21G|    28G|   112K|       |       |  Q4,01 | PCWP |            |
|  26 |      PX RECEIVE          |                           |   270M|    21G|       |   843 |       |       |  Q4,01 | PCWP |            |
|  27 |       PX SEND HASH       | :TQ40000                  |   270M|    21G|       |   843 |       |       |  Q4,00 | P->P | HASH       |
|  28 |        PX BLOCK ITERATOR |                           |   270M|    21G|       |   843 |    28 |    55 |  Q4,00 | PCWC |            |
|* 29 |         TABLE ACCESS FULL| TXN                       |   270M|    21G|       |   843 |    28 |    55 |  Q4,00 | PCWP |            |
|  30 |   PX COORDINATOR         |                           |       |       |       |       |       |       |        |      |            |
|  31 |    PX SEND QC (RANDOM)   | :TQ50001                  |   270M|    21G|       |   112K|       |       |  Q5,01 | P->S | QC (RAND)  |
|  32 |     HASH GROUP BY        |                           |   270M|    21G|    28G|   112K|       |       |  Q5,01 | PCWP |            |
|  33 |      PX RECEIVE          |                           |   270M|    21G|       |   843 |       |       |  Q5,01 | PCWP |            |
|  34 |       PX SEND HASH       | :TQ50000                  |   270M|    21G|       |   843 |       |       |  Q5,00 | P->P | HASH       |
|  35 |        PX BLOCK ITERATOR |                           |   270M|    21G|       |   843 |    28 |    55 |  Q5,00 | PCWC |            |
|* 36 |         TABLE ACCESS FULL| TXN                       |   270M|    21G|       |   843 |    28 |    55 |  Q5,00 | PCWP |            |
|  37 |   PX COORDINATOR         |                           |       |       |       |       |       |       |        |      |            |
|  38 |    PX SEND QC (RANDOM)   | :TQ60001                  |   270M|    21G|       |   112K|       |       |  Q6,01 | P->S | QC (RAND)  |
|  39 |     HASH GROUP BY        |                           |   270M|    21G|    28G|   112K|       |       |  Q6,01 | PCWP |            |
|  40 |      PX RECEIVE          |                           |   270M|    21G|       |   843 |       |       |  Q6,01 | PCWP |            |
|  41 |       PX SEND HASH       | :TQ60000                  |   270M|    21G|       |   843 |       |       |  Q6,00 | P->P | HASH       |
|  42 |        PX BLOCK ITERATOR |                           |   270M|    21G|       |   843 |    28 |    55 |  Q6,00 | PCWC |            |
|* 43 |         TABLE ACCESS FULL| TXN                       |   270M|    21G|       |   843 |    28 |    55 |  Q6,00 | PCWP |            |
|  44 |   PX COORDINATOR         |                           |       |       |       |       |       |       |        |      |            |
|  45 |    PX SEND QC (RANDOM)   | :TQ70001                  |   270M|    21G|       |   112K|       |       |  Q7,01 | P->S | QC (RAND)  |
|  46 |     SORT GROUP BY        |                           |   270M|    21G|    28G|   112K|       |       |  Q7,01 | PCWP |            |
|  47 |      PX RECEIVE          |                           |   270M|    21G|       |   843 |       |       |  Q7,01 | PCWP |            |
|  48 |       PX SEND HASH       | :TQ70000                  |   270M|    21G|       |   843 |       |       |  Q7,00 | P->P | HASH       |
|  49 |        PX BLOCK ITERATOR |                           |   270M|    21G|       |   843 |    28 |    55 |  Q7,00 | PCWC |            |
|* 50 |         TABLE ACCESS FULL| TXN                       |   270M|    21G|       |   843 |    28 |    55 |  Q7,00 | PCWP |            |
-------------------------------------------------------------------------------------------------------------------------------------------

【问题讨论】：

在230分钟的运行时间中，读写临时空间使用了多少？桌子本身占用多少空间？表的分区键列是分组列之一吗？排序是最优的、单通道还是多通道？分组操作总共需要多少行？
在进行度量表连接之前有没有机会聚合事务表？
表本身占用多少空间？ 18 GB 是的，表的分区键也用于聚合，分组后 - 我预计接近 70 亿条记录....如何找到排序是否最佳？
我很想知道查询是否在分区级别运行聚合——请显示查询和查询的解释计划，以及表的 DDL。您使用 V$SQL_WORKAREA 或 V$SQL_WORKAREA_ACTIVE 监控临时空间操作的使用。
@david - 我将分享这个计划......还有一个观察结果是，它在“缓冲排序”上花费了大量时间......有什么办法可以避免这种情况吗？跨度>

标签： performance oracle space temp

【解决方案1】：

为每个分区创建一个查询。由于分区键是聚合列之一，因此每个分区都会生成单独的数据。

将单个语句分成多个较小的语句几乎总是效率较低。但是分区整个表的数据只会被读取一次，即使它被查询了 25 次。此更改应该只比您原来的方法效率稍低，但应该使用更少的临时表空间。除非分区严重倾斜。

begin
    --Loop through all partitions.
    for partition_names in
    (
        select partition_name
        from user_tab_partitions
        where table_name = 'TXN'
    ) loop
        --Execute the statement.
        execute immediate q'<
            WITH IDQ_LKP AS
            ...
            FROM TXN partition (>'||partition_names.partition_name||q'<),LKP
            ...
        >';

        --Normally commits should not be in DML loops, but a commit is required
        --if the statement uses direct-path writes.
        commit;
    end loop;
end;
/

更新 - 单一查询方法和证明它可能有效的证据

每个分区上的查询可以组合成一条 SQL 语句。这应该仍然表现良好并且使用较少的临时表空间，尽管它将是一个非常大的 SQL 语句。

基本思路是：

with lookup as ...
select txn partition (partition1), lookup ... union all
select txn partition (partition2), lookup ... union all
...
select txn partition (partition25), lookup ... union all

这是示例表、示例数据和虚假统计数据：

create table txn(date_pk date, col1 number, col2 number, col3 number, colr number
    ,col5 number, colr_desc number, col5_desc number, record_count number
    ,record_identifier number)
partition by hash (col2)
(
    partition p01,partition p02,partition p03,partition p04,partition p05,
    partition p06,partition p07,partition p08,partition p09,partition p10,
    partition p11,partition p12,partition p13,partition p14,partition p15,
    partition p16,partition p17,partition p18,partition p19,partition p20,
    partition p21,partition p22,partition p23,partition p24,partition p25
);

--A few fake rows just to create a column censity for GROUP BY 
insert into txn
select sysdate, 2, level, level, level, level, level, level, level, level
from dual connect by level <= 100000;

begin
    --Gather mostly for column density.
    --Use GLOBAL because I don't know how to fake partition stats.
    dbms_stats.gather_table_stats(user, 'txn', granularity => 'global');
    --Fake 452M rows.  This number will generate 262G of TempSpc.
    --I can't reproduce it with 20G because I don't know the column densities.
    dbms_stats.set_table_stats(user, 'TXN', numrows => 452000000);
end;
/

这是原始查询，经过一些修饰以使其更小。它仍然包含相同的列、条件和分组。请注意，优化器估计它将使用 262GB 的临时表空间，并且执行与您的非常相似。

explain plan for
WITH IDQ_LKP AS 
(
    SELECT '703' AS METRIC_ID,'desc1' AS EN_METRIC_1_NM FROM DUAL UNION ALL
    SELECT '702' AS METRIC_ID,'desc1' AS EN_METRIC_1_NM FROM DUAL UNION ALL
    SELECT '704' AS METRIC_ID,'% desc1' AS EN_METRIC_1_NM FROM DUAL UNION ALL 
    SELECT '705' AS METRIC_ID,'desc2' AS EN_METRIC_1_NM FROM DUAL UNION ALL 
    SELECT '706' AS METRIC_ID,'desc3' AS EN_METRIC_1_NM FROM DUAL UNION ALL
    SELECT '707' AS METRIC_ID,'desc5' AS EN_METRIC_1_NM FROM DUAL UNION ALL
    SELECT '701' AS METRIC_ID,'desc4' AS EN_METRIC_1_NM FROM DUAL
)
SELECT /*+ parallel(16) */
    col1,col2,'Monthly Snapshots' Time_Rollup,col3,date_pk,colr,col5,colr_DESC,col5_DESC,metric_id,EN_METRIC_1_NM,NULL METRIC_1_LY,NULL METRIC_2_LY,NULL METRIC_3_CY,NULL METRIC_3_LY
    ,sum (CASE WHEN (metric_id='704' AND record_identifier=17 ) THEN nvl ( record_count,0 ) ELSE 0 END ) AS METRIC_1_CY
    ,sum (CASE WHEN (metric_id='703' AND record_identifier=17) THEN nvl ( record_count,0 ) ELSE 0 END ) AS METRIC_2_CY 
FROM TXN,IDQ_LKP
WHERE col1=2
GROUP BY  col1 , col2 , col3 , date_pk , colr , col5 , colr_DESC , col5_DESC, metric_id , EN_METRIC_1_NM;

select * from table(dbms_xplan.display);


Plan hash value: 2764457837

--------------------------------------------------------------------------------------------------------------------------------------------
| Id  | Operation                  | Name     | Rows  | Bytes |TempSpc| Cost (%CPU)| Time     | Pstart| Pstop |    TQ  |IN-OUT| PQ Distrib |
--------------------------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT           |          |  3163M|   179G|       |    67M  (1)| 00:43:46 |       |       |        |      |            |
|   1 |  PX COORDINATOR            |          |       |       |       |            |          |       |       |        |      |            |
|   2 |   PX SEND QC (RANDOM)      | :TQ10002 |  3163M|   179G|       |    67M  (1)| 00:43:46 |       |       |  Q1,02 | P->S | QC (RAND)  |
|   3 |    HASH GROUP BY           |          |  3163M|   179G|   262G|    67M  (1)| 00:43:46 |       |       |  Q1,02 | PCWP |            |
|   4 |     PX RECEIVE             |          |  3163M|   179G|       |    67M  (1)| 00:43:46 |       |       |  Q1,02 | PCWP |            |
|   5 |      PX SEND HASH          | :TQ10001 |  3163M|   179G|       |    67M  (1)| 00:43:46 |       |       |  Q1,01 | P->P | HASH       |
|   6 |       HASH GROUP BY        |          |  3163M|   179G|   262G|    67M  (1)| 00:43:46 |       |       |  Q1,01 | PCWP |            |
|   7 |        MERGE JOIN CARTESIAN|          |  3163M|   179G|       |   488K  (1)| 00:00:20 |       |       |  Q1,01 | PCWP |            |
|   8 |         PX RECEIVE         |          |     7 |    70 |       |    14   (0)| 00:00:01 |       |       |  Q1,01 | PCWP |            |
|   9 |          PX SEND BROADCAST | :TQ10000 |     7 |    70 |       |    14   (0)| 00:00:01 |       |       |  Q1,00 | S->P | BROADCAST  |
|  10 |           PX SELECTOR      |          |       |       |       |            |          |       |       |  Q1,00 | SCWC |            |
|  11 |            VIEW            |          |     7 |    70 |       |    14   (0)| 00:00:01 |       |       |  Q1,00 | SCWC |            |
|  12 |             UNION-ALL      |          |       |       |       |            |          |       |       |  Q1,00 | SCWC |            |
|  13 |              FAST DUAL     |          |     1 |       |       |     2   (0)| 00:00:01 |       |       |  Q1,00 | SCWP |            |
|  14 |              FAST DUAL     |          |     1 |       |       |     2   (0)| 00:00:01 |       |       |  Q1,00 | SCWP |            |
|  15 |              FAST DUAL     |          |     1 |       |       |     2   (0)| 00:00:01 |       |       |  Q1,00 | SCWP |            |
|  16 |              FAST DUAL     |          |     1 |       |       |     2   (0)| 00:00:01 |       |       |  Q1,00 | SCWP |            |
|  17 |              FAST DUAL     |          |     1 |       |       |     2   (0)| 00:00:01 |       |       |  Q1,00 | SCWP |            |
|  18 |              FAST DUAL     |          |     1 |       |       |     2   (0)| 00:00:01 |       |       |  Q1,00 | SCWP |            |
|  19 |              FAST DUAL     |          |     1 |       |       |     2   (0)| 00:00:01 |       |       |  Q1,00 | SCWP |            |
|  20 |         BUFFER SORT        |          |   451M|    21G|       |    67M  (1)| 00:43:46 |       |       |  Q1,01 | PCWP |            |
|  21 |          PX BLOCK ITERATOR |          |   451M|    21G|       |   570  (95)| 00:00:01 |     1 |    25 |  Q1,01 | PCWC |            |
|* 22 |           TABLE ACCESS FULL| TXN      |   451M|    21G|       |   570  (95)| 00:00:01 |     1 |    25 |  Q1,01 | PCWP |            |
--------------------------------------------------------------------------------------------------------------------------------------------

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

  22 - filter("COL1"=2)

Note
-----
   - Degree of Parallelism is 16 because of hint

用多个txn partition (pXX),idq_lkp 替换单个txn,idq_lkp 将最大临时表空间估计从262G 减少到10G。此示例仅包含 25 个分区中的 2 个，但添加更多分区不会增加所需的临时表空间。

explain plan for
WITH IDQ_LKP AS 
(
    SELECT '703' AS METRIC_ID,'desc1' AS EN_METRIC_1_NM FROM DUAL UNION ALL
    SELECT '702' AS METRIC_ID,'desc1' AS EN_METRIC_1_NM FROM DUAL UNION ALL
    SELECT '704' AS METRIC_ID,'% desc1' AS EN_METRIC_1_NM FROM DUAL UNION ALL 
    SELECT '705' AS METRIC_ID,'desc2' AS EN_METRIC_1_NM FROM DUAL UNION ALL 
    SELECT '706' AS METRIC_ID,'desc3' AS EN_METRIC_1_NM FROM DUAL UNION ALL
    SELECT '707' AS METRIC_ID,'desc5' AS EN_METRIC_1_NM FROM DUAL UNION ALL
    SELECT '701' AS METRIC_ID,'desc4' AS EN_METRIC_1_NM FROM DUAL
)
SELECT /*+ parallel(16) */
    col1,col2,'Monthly Snapshots' Time_Rollup,col3,date_pk,colr,col5,colr_DESC,col5_DESC,metric_id,EN_METRIC_1_NM,NULL METRIC_1_LY,NULL METRIC_2_LY,NULL METRIC_3_CY,NULL METRIC_3_LY
    ,sum (CASE WHEN (metric_id='704' AND record_identifier=17 ) THEN nvl ( record_count,0 ) ELSE 0 END ) AS METRIC_1_CY
    ,sum (CASE WHEN (metric_id='703' AND record_identifier=17) THEN nvl ( record_count,0 ) ELSE 0 END ) AS METRIC_2_CY 
FROM TXN partition (p01),IDQ_LKP
WHERE col1=2
GROUP BY  col1 , col2 , col3 , date_pk , colr , col5 , colr_DESC , col5_DESC, metric_id , EN_METRIC_1_NM
union all
SELECT /*+ parallel(16) */
    col1,col2,'Monthly Snapshots' Time_Rollup,col3,date_pk,colr,col5,colr_DESC,col5_DESC,metric_id,EN_METRIC_1_NM,NULL METRIC_1_LY,NULL METRIC_2_LY,NULL METRIC_3_CY,NULL METRIC_3_LY
    ,sum (CASE WHEN (metric_id='704' AND record_identifier=17 ) THEN nvl ( record_count,0 ) ELSE 0 END ) AS METRIC_1_CY
    ,sum (CASE WHEN (metric_id='703' AND record_identifier=17) THEN nvl ( record_count,0 ) ELSE 0 END ) AS METRIC_2_CY 
FROM TXN partition (p02),IDQ_LKP
WHERE col1=2
GROUP BY  col1 , col2 , col3 , date_pk , colr , col5 , colr_DESC , col5_DESC, metric_id , EN_METRIC_1_NM;


select * from table(dbms_xplan.display);

Plan hash value: 260310120

-----------------------------------------------------------------------------------------------------------------------------------------------------------------
| Id  | Operation                      | Name                      | Rows  | Bytes |TempSpc| Cost (%CPU)| Time     | Pstart| Pstop |    TQ  |IN-OUT| PQ Distrib |
-----------------------------------------------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT               |                           |   253M|    14G|       |  3923K (51)| 00:02:34 |       |       |        |      |            |
|   1 |  TEMP TABLE TRANSFORMATION     |                           |       |       |       |            |          |       |       |        |      |            |
|   2 |   LOAD AS SELECT               | SYS_TEMP_0FD9D66A0_D66798 |       |       |       |            |          |       |       |        |      |            |
|   3 |    UNION-ALL                   |                           |       |       |       |            |          |       |       |        |      |            |
|   4 |     FAST DUAL                  |                           |     1 |       |       |     2   (0)| 00:00:01 |       |       |        |      |            |
|   5 |     FAST DUAL                  |                           |     1 |       |       |     2   (0)| 00:00:01 |       |       |        |      |            |
|   6 |     FAST DUAL                  |                           |     1 |       |       |     2   (0)| 00:00:01 |       |       |        |      |            |
|   7 |     FAST DUAL                  |                           |     1 |       |       |     2   (0)| 00:00:01 |       |       |        |      |            |
|   8 |     FAST DUAL                  |                           |     1 |       |       |     2   (0)| 00:00:01 |       |       |        |      |            |
|   9 |     FAST DUAL                  |                           |     1 |       |       |     2   (0)| 00:00:01 |       |       |        |      |            |
|  10 |     FAST DUAL                  |                           |     1 |       |       |     2   (0)| 00:00:01 |       |       |        |      |            |
|  11 |   UNION-ALL                    |                           |       |       |       |            |          |       |       |        |      |            |
|  12 |    PX COORDINATOR              |                           |       |       |       |            |          |       |       |        |      |            |
|  13 |     PX SEND QC (RANDOM)        | :TQ10002                  |   126M|  7362M|       |  1961K  (1)| 00:01:17 |       |       |  Q1,02 | P->S | QC (RAND)  |
|  14 |      HASH GROUP BY             |                           |   126M|  7362M|    10G|  1961K  (1)| 00:01:17 |       |       |  Q1,02 | PCWP |            |
|  15 |       PX RECEIVE               |                           |   126M|  7362M|       |  1961K  (1)| 00:01:17 |       |       |  Q1,02 | PCWP |            |
|  16 |        PX SEND HASH            | :TQ10001                  |   126M|  7362M|       |  1961K  (1)| 00:01:17 |       |       |  Q1,01 | P->P | HASH       |
|  17 |         HASH GROUP BY          |                           |   126M|  7362M|    10G|  1961K  (1)| 00:01:17 |       |       |  Q1,01 | PCWP |            |
|  18 |          MERGE JOIN CARTESIAN  |                           |   126M|  7362M|       | 19567   (1)| 00:00:01 |       |       |  Q1,01 | PCWP |            |
|  19 |           PX RECEIVE           |                           |     7 |    70 |       |     2   (0)| 00:00:01 |       |       |  Q1,01 | PCWP |            |
|  20 |            PX SEND BROADCAST   | :TQ10000                  |     7 |    70 |       |     2   (0)| 00:00:01 |       |       |  Q1,00 | P->P | BROADCAST  |
|  21 |             VIEW               |                           |     7 |    70 |       |     2   (0)| 00:00:01 |       |       |  Q1,00 | PCWP |            |
|  22 |              PX BLOCK ITERATOR |                           |     7 |    70 |       |     2   (0)| 00:00:01 |       |       |  Q1,00 | PCWC |            |
|  23 |               TABLE ACCESS FULL| SYS_TEMP_0FD9D66A0_D66798 |     7 |    70 |       |     2   (0)| 00:00:01 |       |       |  Q1,00 | PCWP |            |
|  24 |           BUFFER SORT          |                           |    18M|   879M|       |  1961K  (1)| 00:01:17 |       |       |  Q1,01 | PCWP |            |
|  25 |            PX BLOCK ITERATOR   |                           |    18M|   879M|       |    23  (92)| 00:00:01 |     1 |     1 |  Q1,01 | PCWC |            |
|* 26 |             TABLE ACCESS FULL  | TXN                       |    18M|   879M|       |    23  (92)| 00:00:01 |     1 |     1 |  Q1,01 | PCWP |            |
|  27 |    PX COORDINATOR              |                           |       |       |       |            |          |       |       |        |      |            |
|  28 |     PX SEND QC (RANDOM)        | :TQ20002                  |   126M|  7362M|       |  1961K  (1)| 00:01:17 |       |       |  Q2,02 | P->S | QC (RAND)  |
|  29 |      HASH GROUP BY             |                           |   126M|  7362M|    10G|  1961K  (1)| 00:01:17 |       |       |  Q2,02 | PCWP |            |
|  30 |       PX RECEIVE               |                           |   126M|  7362M|       |  1961K  (1)| 00:01:17 |       |       |  Q2,02 | PCWP |            |
|  31 |        PX SEND HASH            | :TQ20001                  |   126M|  7362M|       |  1961K  (1)| 00:01:17 |       |       |  Q2,01 | P->P | HASH       |
|  32 |         HASH GROUP BY          |                           |   126M|  7362M|    10G|  1961K  (1)| 00:01:17 |       |       |  Q2,01 | PCWP |            |
|  33 |          MERGE JOIN CARTESIAN  |                           |   126M|  7362M|       | 19567   (1)| 00:00:01 |       |       |  Q2,01 | PCWP |            |
|  34 |           PX RECEIVE           |                           |     7 |    70 |       |     2   (0)| 00:00:01 |       |       |  Q2,01 | PCWP |            |
|  35 |            PX SEND BROADCAST   | :TQ20000                  |     7 |    70 |       |     2   (0)| 00:00:01 |       |       |  Q2,00 | P->P | BROADCAST  |
|  36 |             VIEW               |                           |     7 |    70 |       |     2   (0)| 00:00:01 |       |       |  Q2,00 | PCWP |            |
|  37 |              PX BLOCK ITERATOR |                           |     7 |    70 |       |     2   (0)| 00:00:01 |       |       |  Q2,00 | PCWC |            |
|  38 |               TABLE ACCESS FULL| SYS_TEMP_0FD9D66A0_D66798 |     7 |    70 |       |     2   (0)| 00:00:01 |       |       |  Q2,00 | PCWP |            |
|  39 |           BUFFER SORT          |                           |    18M|   879M|       |  1961K  (1)| 00:01:17 |       |       |  Q2,01 | PCWP |            |
|  40 |            PX BLOCK ITERATOR   |                           |    18M|   879M|       |    23  (92)| 00:00:01 |     2 |     2 |  Q2,01 | PCWC |            |
|* 41 |             TABLE ACCESS FULL  | TXN                       |    18M|   879M|       |    23  (92)| 00:00:01 |     2 |     2 |  Q2,01 | PCWP |            |
-----------------------------------------------------------------------------------------------------------------------------------------------------------------

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

  26 - filter("COL1"=2)
  41 - filter("COL1"=2)

Note
-----
   - Degree of Parallelism is 16 because of hint

【讨论】：

对不起，我必须在纯 SQL 中实现这一点......这是我们内部工具的限制......
您可以使用 25 个不同查询中的 UNION ALL 来完成此操作。这将是一个非常庞大的查询，但我认为它会很快并且使用更少的表空间。明天我会尝试发布更多细节。
嗨 Joanearles，谢谢....我将尝试我的方案并回复给您...后续问题 - 我的原始查询能够实现分区修剪...是这样吗相当于在“UNION ALL”模式下查询单个分区？
是的，我相信是的。但是分区修剪是不够的。为了减少临时表空间，必须一次处理一个分区。通常这可以通过分区连接来实现。但由于此查询连接到如此小的表，因此没有简单的方法来实现。

【解决方案2】：

我对您的请求的评论不知何故没有被听到。再说一遍：为了避免巨大的中间数据，请事先减少它。请尝试以下方法。首先大表被预先聚合，然后交叉连接，然后再次聚合。这减少了笛卡尔积中的中间数据。这可能会解决您的问题。

select 
  col1, col2, 'Monthly Snapshots' AS Time_Rollup, col3, date_pk, colr, col5, colr_DESC, col5_DESC, metric_id, en_metric_1_nm
  , sum 
  (
    case
    when (metric_id='704' and record_identifier=17 )
     or (metric_id='705' and record_identifier=123)
     or (metric_id='706' and record_identifier=43)
     or (metric_id='707' and record_identifier=34) then
      sum_record_count
    when metric_id not in ('704','705','706','707') then
      null
    else 
      0
    end
  ) as metric_1_cy
  , null as metric_1_ly 
  , sum 
  (
    case
    when (metric_id='703' and record_identifier=17)
     or (metric_id='705' and record_identifier=777 )
     or (metric_id='702' and record_identifier=123 )
     or (metric_id='704' and record_identifier=17 )
     or (metric_id='706' and record_identifier=99999997 )
     or (metric_id='707' and record_identifier=99999996) then
      sum_record_count
    when metric_id not in ('702','703','704','705','706','707') then
      null
    else 
      0
    end
  ) as metric_2_cy
  , null as metric_2_ly
  , null as metric_3_cy 
  , null as metric_3_ly
from
(
  select col1, col2, col3, date_pk, colr, col5, colr_desc, col5_desc, record_identifier, 
    sum(nvl(record_count,0)) as sum_record_count
  from txn
  where col1=2
  group by col1, col2, col3, date_pk, colr, col5, colr_desc, col5_desc, record_identifier
) pre_aggregate
cross join 
(
  select '703' as metric_id,'desc1' as en_metric_1_nm from dual
  union all
  select '702' as metric_id,'desc1' as en_metric_1_nm from dual
  ...
) lkp 
group by col1, col2, col3, date_pk, colr, col5, colr_DESC, col5_DESC, metric_id, en_metric_1_nm;

【讨论】：

谢谢...我现在正在测试它...我会恢复的
我是这个论坛的新手，有什么方法可以格式化和粘贴查询/计划吗？
我试过了，失败了，因为它消耗了超过 150 GB 的临时空间
很抱歉听到这个消息。好吧，150 GB 比 250 GB 好，不是吗 :-) 无论如何，交叉连接似乎太贵了。您是否尝试过使用单独的语句和联合所有的预聚合技术？

【解决方案3】：

仅查看查询，我考虑尝试的一种方法是改变这种实现方法：

将大表连接到小表
计算指标值
聚合到所需级别

...到这个...

将大表聚合到所需级别（如果可能，应用过滤器以删除不需要的行）。
加入小表
计算指标
可能再次聚合

这应该需要一个较小的临时数据集。

【讨论】：

获取两种方法的解释计划
我已经粘贴了新方法的解释，请看一下并提出建议......提前致谢......
三个分组操作？
如果我使用全局临时表会有帮助吗？

【解决方案4】：

看起来您可以让选项 2 的七个独立查询在不同的 CPU 上并行运行。也许设置某种视图来解决合并结果的需要？

【讨论】：

它已经并行运行...它是一个提取作业..所以视图不会有帮助
是的，我在提交后看到了 Oracle 标记。我认为你的硬件可能是有能力的，因为只有七个线程。