(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.
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