The Veeam Backup & Replication console is slow to respond when switching between different views. The issue is more noticeable when attempting to search through the history of jobs.
In rare cases the VeeamBackup SQL DB can have many thousands of previous task sessions which causes queries run by the console to be delayed.
Note: If you are using Veeam Backup & Replication 9.5 U3 (22.214.171.1246), and are observing slow GUI performance within the console, this may be related to a known issue found only in 126.96.36.1996. This was corrected in the next update, please ensure you have the latest update installed, https://www.veeam.com/updates.html.
There are two parts to resolving this, one resolves the issue in the short term by removing old sessions from the SQL DB, the other is to limit how many sessions are stored in the SQL DB.
The sessions to be stored in the configuration database are controlled by retention defined in number of weeks. If you have many jobs running often the default setting may cause the database to retain many entries. You can specify session history settings within the Veeam Backup & Replication console.