(this blog post applies to MySQL Cluster 6.3 and MySQL Cluster
6.4/7.0)
A while ago I discussed Memory Allocation in MySQL Cluster. Here it
comes again, but we also discuss fragmentation and a tool to help analyze if there is
fragmentation.
The main problem I want to address here is that "I filled up 100%
of my DataMemory, then deleted 40% and I cannot create a new
table!!". Now this is not such a common problem, but can happen
in systems with a lot of insert/deletes (especially on VAR*
columns), and can be an issue if you need to create a new table.
If the allocation patterns are always on the same set of tables,
then this is less of an issue.
Allocation
- If the table is empty and there …