A feature which hasn't been so public about the implementation
of partitioning is the support for atomicity of many ALTER TABLE
statements using partitioned tables.
This atomicity exists for
ALTER TABLE ADD PARTITION ....
ALTER TABLE REORGANIZE PARTITION ...
ALTER TABLE DROP PARTITION ...
ALTER TABLE COALESCE PARTITION
Given that partitioning often works with very large tables it
was desirable to have a higher level of security for ALTER TABLE
of partitioned tables. To support this a DDL log was implemented.
This DDL log will in future versions be used also for many other
meta data statements. The DDL log will record all files added,
renamed and dropped during an ALTER TABLE command as above.
The design is done in such a way that the ALTER TABLE will either
fail and then all [Read more...]