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What should the memory usage be for MySQL?
In general, when I worked as a systems administrator, we aimed for MySQL services to consume no more than 25% of a server’s available memory at a maximum in order to have a better likelihood of avoiding out of memory scenarios.
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.
Is it good to swap out memory in MySQL?
It is fine to have some used space in your swap file, as there are probably parts of the operating system that are unused when MySQL is running, and it’s a good idea to swap them out. What you don’t want is constant swapping going on during the operation, which is easily seen in the “si” and “so” columns in the vmstat output.
When to kill MySQL due to out of memory error?
If you’ve made a mistake in the MySQL configuration, or you have some rogue process taking much more memory than expected, it is usually a much better situation to lose performance due to a swap then to kill MySQL with an out of memory (OOM) error – potentially causing downtime.
This value needs to be kept below 90% of the server memory for a dedicated database server. In a case of a shared server, it should be kept below 50% of the server memory. Check some MySQL settings that help in determining the memory usage which will help you to decide its size.
How does MySQL dynamically allocate memory during startup?
MySQL also has a Performance Schema which is a feature for monitoring MySQL activities at a low level. Once this is enabled, it dynamically allocates memory incrementally, scaling its memory use to actual server load, instead of allocating required memory during server startup.
Why is MySQL swapping out its memory to disk?
Either way, it’s probable that MySQL is swapping out its memory to disk. This is oftentimes a very common situation especially when MySQL server and the underlying hardware is not set optimally in parallel to the expected requirements.
How does MySQL allocate memory for temporary tables?
MySQL also allocates memory for temporary tables unless it becomes too large (determined by tmp_table_size and max_heap_table_size ).