Make sure you are running the database maintenance script (pandora_db) every hour. This is detailed in the installation instructions and may be an overlooked or unconfigured step. Launch it by hand and verify that there is no error.
If your system has many agents, you should disable the hourly packet collection graph statistics for each agent (Setup -> Performance -> Use agent access graph), this puts a lot of load on the system and is not recommended for environments with several hundred agents.
You should ensure that event data histories do not exceed seven days, and data retention does not exceed one month.
Check that the disk read/write on your machine has an adequate speed, we recommend the use of SSD and M2 disks for their high speed. The recommended speed is 500MB/s or higher.
You can “tune” the DB configuration file as follows (example shown for an environment with 8GB of RAM). Parameters like innodb_buffer_pool_size or innodb_io_capacity depend heavily on the hardware (memory, disk) of the server. See the documentation for more details. A correct MySQL server configuration can speed up your system performance by up to 10 times.
An example of the content of a MySQL configuration file (/etc/my.cnf) is in our wiki.