UPDATE查询已挂起

Question

我有以下查询

UPDATE rec_analyst
           SET analyst_name = (SELECT DISTINCT min (LIQA_ANALYST_LAST_NAME)
                                 FROM LIQA
                                WHERE LIQA_ANALYST_ID = analyst_extern_id
                                      AND LIQA_TS_INSERT = '15.09.2011'

                               )
         WHERE analyst_provider_id = 4

解释计划显示大约4000的成本，但数据库负载是100％，甚至一小时后这个工作还没有准备好。 这里的解释计划输出：

------------------------------------------------------------------------------------
DESC                            |OBJECT NAME                    |COST| #    |BYTES  | 
------------------------------------------------------------------------------------
UPDATE STATEMENT, GOAL =ALL_ROWS|                               |  34| 16572| 331440|
-------------------------------------------------------------------------------------
  UPDATE                        |REC_ANALYST                    |    |      |       |
-------------------------------------------------------------------------------------
   TABLE ACCESS FULL            |REC_ANALYST                    |  34| 16572|331440 |
-------------------------------------------------------------------------------------
  SORT AGGREGATE                |                               |    |      |24     |
-------------------------------------------------------------------------------------
   TABLE ACCESS FULL            |REC_LIQA_LOAD_INQUIRY_ANALYST  |3965|1     |24     |
-------------------------------------------------------------------------------------

我该如何优化它？

Answer 1

你可以尝试：

MERGE INTO rec_analyst ra
USING ( SELECT LIQA_ANALYST_ID analyst_id, MIN(LIQA_ANALYST_LAST_NAME) min_name
          FROM LIQA
         WHERE LIQA_TS_INSERT = '15.09.2011'
         GROUP BY LIQA_ANALYST_ID
      ) liqa_extract
   ON ( liqa_extract.analyst_id = ra.analyst_extern_id
        AND ra.analyst_provider_id = 4
      )
 WHEN MATCHED THEN UPDATE SET ra.analyst_name = liqa_extract.min_name;

Answer 2

询问您的DBA是否有可能/有利于在以下任何一个（最好是两个）上添加索引：

表：rec_analyst列：analyst_provider_id 表：LIQA列：LIQA_TS_INSERT

理想情况下，LIQA.analyst_id和rec_analyst.analyst_extern_id上有PK / FK索引，不知道您的架构认为很难说哪些索引会对整个系统有所帮助。