Question about Number of Partitions for "partition by key"

[Mike van Lammeren]

Hello!

I'm in the very early development stage of a project that is using MySQL
Cluster. After reading Andrew Morgan's blog about partitioning, (
http://www.clusterdb.com/mysql-cluster/intelligent-user-controlled-partitioning-and-writing-distribution-aware-ndb-api-applications/<http://www.clusterdb.com/mysql-cluster/intelligent-user-controlled-partitioning-and-writing-distribution-aware-ndb-api-applications/#comments>),
I added *'pa**rtition by key'* to my tables, wherever appropriate. The *explain
partitions* command is particularly helpful.

Recently, I used MySQL Workbench to make some nice pictures for our
documentation, and for the first time, noticed that you can specify the
number of partitions used for the *'p**artition by key'* command. Which
leads to my question:

How many partitions should I set?

Is it best to just leave the *'partition**s'* phrase off the table
definition? If I do, what does MySQL Cluster set by default?

I currently have two data nodes. In the future, when I add a data node, what
do I do with the number of partitions? Does it have to match the number of
data nodes?

Mike van Lammeren