【赛迪网－IT技术报道】Oracle 10g分区表维护中的两个注意事项:
1.全局索引
SQL> alter table analyse_content truncate subpartition DATA0712_DEYANG;
Table truncated
truncate分区后，修改或者插入数据报错：
ORA-01502: index 'phs.pk' or partition of such index is in unusable state
这个时候只能rebuild index
SQL> alter index phs.pk rebuild;
Index altered
执行以后恢复正常，或者使用如下语句：
SQL> alter table analyse_content truncate subpartition DATA0712_ZIGONG UPDATE
GLOBAL INDEXES;
Table truncated
这样它会自动恢复索引。
2.物化视图
对于已经建有fast refresh view的分区表来说，truncate和drop分区/表会导致物化视图出错。
SQL> alter table analyse_content drop subpartition DATA0712_MIANYANG;
Table altered
SQL> alter table analyse_content truncate subpartition DATA0712_LUZHOU;
Table truncated
再次查询物化视图，这个两个分区的数据仍然存在，说明物化视图不能对这种DDL语句进行更新。
尝试在基础表插入数据，报错：
ORA-32313: REFRESH FAST of " " unsupported after PMOPs
这时候必须手工刷新MV
SQL> exec dbms_mview.refresh('mv_analyse_content','f');
begin dbms_mview.refresh('mv_analyse_content','f'); end;
ORA-32313: PMOP 之后不支持 "PHS"."MV_ANALYSE_CONTENT" 的 REFRESH FAST
ORA-06512: 在 "SYS.DBMS_SNAPSHOT", line 2255
ORA-06512: 在 "SYS.DBMS_SNAPSHOT", line 2461
ORA-06512: 在 "SYS.DBMS_SNAPSHOT", line 2430
ORA-06512: 在 line 1
看来快速刷新'f'是不行，还是得完全刷新'c'
SQL> exec dbms_mview.refresh('mv_analyse_content','c');
PL/SQL procedure successfully completed
执行完后，MV里面的数据恢复正常，基表不再报错。
实际10g里面，truncate分区后，某些物化视图可以执行fast refresh，具体有很多限制，
要查询doc，反正select * from table这种视图肯定可以'f',不过却没有什么意义。
---2008 04 22 在doc上找到了PCT特性的限制，如下：
At least one of the detail tables referenced by the materialized view must be
partitioned.
Partitioned tables must use either range, list or composite partitioning.
The top level partition key must consist of only a single column.
The materialized view must contain either the partition key column or a partition
marker or ROWID or join dependent expression of the detail table. See Oracle
Database PL/SQL Packages and Types Reference for details regarding the DBMS_
MVIEW.PMARKER function.
If you use a GROUP BY clause, the partition key column or the partition marker or
ROWID or join dependent expression must be present in the GROUP BY clause.
If you use an analytic window function or the MODEL clause, the partition key
column or the partition marker or ROWID or join dependent expression must be
present in their respective PARTITION BY subclauses.
Data modifications can only occur on the partitioned table. If PCT refresh is being
done for a table which has join dependent expression in the materialized view,
then data modifications should not have occurred in any of the join dependent
tables.
The COMPATIBILITY initialization parameter must be a minimum of 9.0.0.0.0.
PCT is not supported for a materialized view that refers to views, remote tables, or
outer joins.
PCT-based refresh is not supported for UNION ALL materialized views.
对于海量数据库，如果不能使用DROP分区，则delete相当慢。
如果使用了，又会导致完全刷新MV，同样慢。
在物化视图的时候要认真考虑PCT特性。
对于分区表 已经相关索引，快照的维护，建议还是参考Oracle的DOC，在admin guide和
dataware house guide里有非常完善描述。虽然没有涉及internal，但完全可以满足应用。
（责任编辑：卢兆林）
