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How does MySQL NDB Cluster work?
NDB Cluster is transactional, supporting the READ COMMITTED transaction isolation level. NDB Cluster is ACID compliant, though with the assumption that two data nodes in the same node group do not crash within two seconds of each other. The data nodes support retrieving data in parallel even for a single query.
What is the difference between clustering and replication?
For example, if data is replicated between two locations then it is possible for a database to access each data set and answer queries submitted to it. Then these two database instances would be considered to be a database cluster.
How much memory does a MySQL server need?
The default configuration is designed to permit a MySQL server to start on a virtual machine that has approximately 512MB of RAM. You can improve MySQL performance by increasing the values of certain cache and buffer-related system variables.
How many cores can MySQL 5.6 scale up to?
MySQL 5.5 and Percona’s XtraDB are making that somewhat better in InnoDB; the practical limit for cores is more like 32, and performance tends plateaus after that rather than declining. 5.6 claims to scale up to about 48 cores. HyperThreading is mostly a thing of the past, so this section may not apply.
What’s the first rule of MySQL memory usage?
The first rule of configuring MySQL memory usage is you never want your MySQL to cause the operating system to swap. Even minor swapping activity can dramatically reduce MySQL performance. Note the keyword “activity” here.
What should MySQL buffer size be for 16GB?
Considering the 5-7% overhead that the InnodB Buffer Pool has, a sensible setting is innodb_buffer_pool_size=12G – what we very commonly see working well for systems with 16GB of memory. Now that we have configured MySQL memory usage, we also should look at the OS configuration.