使用groupby和where子句在提交时快速刷新

Question

我能够成功创建如下的实例化视图，但是当我查看MV_CAPABILITIES_TABLE时，它告诉我REFRESH_FAST_AFTER_ONETAB_DML和REFRESH_FAST_ANY_DML是不可能的。

CREATE MATERIALIZED VIEW MV_contacts_table
BUILD IMMEDIATE
REFRESH FAST ON COMMIT AS
SELECT t.ID AS ID,
MAX(DECODE(t.FieldName, 'FirstName', t.FieldValue)) FirstName, 
MAX(DECODE(t.FieldName, 'LastName', t.FieldValue)) LastName,
COUNT(*) AS NUM_FIELDS FROM Contacts_Table t
WHERE t.FieldName = 'FirstName' OR t.FieldName = 'LastName'
GROUP BY t.ID

这是MV_CAPABILITIES_TABLE

PCT                             N               
REFRESH_COMPLETE                Y               
REFRESH_FAST                    Y               
REWRITE                         N               
PCT_TABLE                       N   CONTACTS_TABLE  675 2068    relation is not a partitioned table
REFRESH_FAST_AFTER_INSERT       Y               
REFRESH_FAST_AFTER_ONETAB_DML   N                       2086    mv uses the MIN or MAX aggregate functions
REFRESH_FAST_AFTER_ANY_DML      N                       2161    see the reason why REFRESH_FAST_AFTER_ONETAB_DML is disabled
REFRESH_FAST_PCT                N                       2157    PCT is not possible on any of the detail tables in the materialized view
REWRITE_FULL_TEXT_MATCH         N                       2159    query rewrite is disabled on the materialized view
REWRITE_PARTIAL_TEXT_MATCH      N                       2159    query rewrite is disabled on the materialized view
REWRITE_GENERAL                 N                       2159    query rewrite is disabled on the materialized view
REWRITE_PCT                     N                       2158    general rewrite is not possible or PCT is not possible on any of the detail tables
PCT_TABLE_REWRITE               N   CONTACTS_TABLE  675 2068    relation is not a partitioned table

如果删除where子句，则可以使用REFRESH_FAST_AFTER_ANY_DML。是否有可能可以对该SQL查询进行调整，以使我的实例化视图设置为REFRESH_FAST_AFTER_ANY_DML并包含Where子句？

Answer 1

这是restriction of materialized views：

  

删除后可快速刷新具有MAX或MIN的实例化视图   或混合的DML语句如果没有WHERE子句。

     

删除或混合DML后的最大/最小快速刷新没有   与仅插入情况相同的行为。它删除并重新计算   受影响组的最大值/最小值。您需要知道它的   性能影响。

（重点是我的）。

因此，您需要找到其他方法来实现自己的目标。