They include the ability to: detect and tune performance changes, package incidents for support, and do hot fixes and online application upgrades. Townsend notes that large, business-critical applications can often remain unavailable for hours while an upgrade is installed. Oracle Database 11g, he says, allows online application upgrades to be done while the application remains continuously available. "The pre-upgrade application and the post-upgrade application can be used at the same time [and] each end-user session is rolled over on its own schedule." Support for online hot patching is another key 11g "change management" capability, according to Townsend's presentation. While Oracle already supports rolling patches between nodes in a cluster, he says the forthcoming release adds online patching of a running Oracle executable (single instance or cluster) with no downtime.