It would be nice if JIRA had a database latency check similar to what Confluence has in the System Information page, which performs the following test to return a value:

The latency is calculated by sending a trivial request to the database, querying a table which is known to have only one column and one row. ("select * from CLUSTERSAFETY"). Obviously this query should be blazing fast, and return within 1 or 2 milliseconds.

From https://confluence.atlassian.com/doc/performance-tuning-130289.html

Note on the implementation

The latency measurement is added to the support zip. It's available in application-properties/application.xml under <Database-latency-measurement-milliseconds> element.