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.
What’s the best way to reduce 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. It is fine to have some used space in your swap file,…
Is it bad to configure memory usage in MySQL?
But configuring it incorrectly can result in even worse performance (or even crashes). 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.
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.
What causes MySQL to have poor response time?
But in its default settings, MySQL tries to use all of server’s memory, causing swap to be used; And swap usage leads to poor speed and response times. When we find an unoptimized MySQL server, we run an audit and fix incorrect settings. Some common ones we tweak are:
But configuring it incorrectly can result in even worse performance (or even crashes). The first rule of configuring MySQL memory usage is you never want your MySQL to cause the operating system to swap.
What causes mysql query speed to go down?
Busy MySQL databases go through thousands of data insertions and deletions per week. All this data deletion leaves “holes” in the database, which is called fragmentation. When fragmentation in a MySQL table goes above 15%, it might affect the query speed. But this usually becomes a problem only for databases that are more than 1 GB in size.