标签：oracle online table redefin
联机重定义功能是通过物化视图来实现的。在调用START_REDEF_TABLE存储过程时，会自动创建与临时表名称相同的物化视图，并将源表的记录拷贝到临时表，此时源表可以DML和查询，不可DDL。Table redefinition is started by the DBA creating an interim table based on the original table. The interim table can have a different structure than the original table, and will eventually take the original table‘s place in the database. While the table is redefined, DML operations on the original table are captured in a Materialized View Log table (MLOG$_%). These changes are eventually transformed and merged into the interim table. When done, the names of the original and the interim tables are swapped in the data dictionary. At this point all users will be working on the new table and the old table can be dropped.
oracle_online table redefinition_2
标签：oracle online table redefin
原文地址：http://blog.51cto.com/7499131/2107004
