Re: OPTIMIZE TABLE not reclaiming memory usage after adding data nodes

[Mikael Ronström]

OPTIMIZE TABLE is supported also in MySQL 5.7-based clusters, nothing has changed there.

OPTIMIZE TABLE only optimizes the pages used for variable sized rows.
The fixed size rows are using rowid's that are essential for node
restarts. This means that the only manner of compressing this data
is to essentially delete the row and insert it again.

In your case all columns are fixed size, so you should change the table
to use variable sized memory for your columns. You can control this
when you create table.

There will always be a header in fixed size memory, but this need not contain
any columnar data. This will make it easier to optimize memory usage of the
table.