"alter table move tablespace" tips Oracle Database Tips by Donald Burleson

 

Question: I want to use the "alter table move tablespace" command to reorganize tables to remove fragmentation.  Does the "alter table move tablespace" command preserve my index and constraint definitions?

 

Answer: Oracle has many ways to reorganize tables, including "alter table move", plus create table as select (CTAS), dbms_redefinition, and data pump export import (expdp, impdp).

When using the alter table move tablespace syntax, make sure to define two tablespaces of the same size to receive the tables, back-and-forth.  I use the names tablename_flip and tablename_flop.

 

alter table fred move tablespace fred_flip;

Also make sure that the target tablespace has enough room to accept the new table

 

ORA-01652: unable to extend temp segment by 16384 in tablespace FRED_FLOP;

 

According Rampant author Mike Hordila, the alter table move tablespace syntax preserves the index and constraint definitions:

"The table move will change the ROWIDs of the table rows, and as such the indexes, which are based on ROWIDs, will become invalid (UNUSABLE).

 

Therefore, the need to execute step two immediately after step one - rebuild the invalid indexes on the current table.
 

At the same time an advantage of using the table move procedure is all constraints are preserved, and index definitions are also saved, so that re-indexing is possible using the fast index REBUILD method, rather than the slower index DROP and CREATE method."

Also, see my notes here:

 

 

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