The concept of high availability in databases refers to the ability of a system to remain operational and accessible even in the event of hardware or software failures, network outages, or other disruptions. A highly available database ensures that transactions can be processed and recorded reliably without interruption or data loss. However, when evaluating a database's reliability claims, it is essential to understand exactly what their version of high availability really means in the context of your specific use case and business needs. Many databases claim to offer high availability but do not provide transparent SLAs (service level agreements) that define the level of service they guarantee to supply at all times. A database's 100% uptime guarantee is often misleading, as it may only refund a percentage of the monthly bill in the event of downtime. Instead, look for databases with four nines of uptime (99.99%) or higher, which translates to less than one minute of downtime per year. Among distributed SQL databases, CockroachDB offers 99.999% uptime (5 minutes and 18 seconds per year) without an asterisk, making it a suitable option for mission-critical systems powering payments and always-accurate payment experiences.