Monday, April 21, 2008

What is table-reorg

Table-reorg is the the procedure which will be executed on "alter table X add partitions Y" .
This you would typically do when you have added Y new nodes to your cluster.

The procedure is online, i.e transactions can run during the operation
and no extra memory will be needed on the "old" nodes.

The reorg is based on linear hashing (but wo/ the normal skewness in distribution)
E.g when going from 2 to 4 partitions 50% of the rows will be moved.

The copying is done in parallel on the "old" nodes,
and consistency is kept using triggers.


So I have atleast 1 reader...

No comments: