使用 groupby 和 where 子句在提交时快速刷新
Refresh fast on commit with groupby and where clause
我能够成功创建如下所示的实体化视图，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
这里是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
如果我删除 where 子句，则 REFRESH_FAST_AFTER_ANY_DML 是可能的。是否有可能调整此 SQL 查询，以便我的物化视图设置为 REFRESH_FAST_AFTER_ANY_DML 并包含 Where 子句？
这是一个restriction of materialized views:
A materialized view with MAX or MIN is fast refreshable after delete
or mixed DML statements if it does not have a WHERE clause.
The max/min fast refresh after delete or mixed DML does not have the
same behavior as the insert-only case. It deletes and recomputes the
max/min values for the affected groups. You need to be aware of its
performance impact.
（强调我的）。
所以你需要找到一些其他的方法来实现你的目标。
我能够成功创建如下所示的实体化视图，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
这里是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
如果我删除 where 子句，则 REFRESH_FAST_AFTER_ANY_DML 是可能的。是否有可能调整此 SQL 查询，以便我的物化视图设置为 REFRESH_FAST_AFTER_ANY_DML 并包含 Where 子句？
这是一个restriction of materialized views:
A materialized view with MAX or MIN is fast refreshable after delete or mixed DML statements if it does not have a WHERE clause.
The max/min fast refresh after delete or mixed DML does not have the same behavior as the insert-only case. It deletes and recomputes the max/min values for the affected groups. You need to be aware of its performance impact.
（强调我的）。
所以你需要找到一些其他的方法来实现你的目标。