CreateSystemTableInTxn is a function to inject a new system table.

FirstUpgradeFromRelease implements the tenant upgrade step for all V[0-9]+_[0-9]+Start cluster versions, which is every first internal version following each major release version.

FirstUpgradeFromReleasePrecondition is the precondition check for upgrading from any supported major release.

GetUpgrade returns the upgrade corresponding to this version if one exists.

NoTenantUpgradeFunc is a TenantUpgradeFunc that doesn't do anything.

TestingSetFirstUpgradePreconditionAOST allows tests to disable withAOST trick in upgrade precondition check, which otherwise can produce false negative.

RunFirstUpgradePrecondition short-circuits FirstUpgradeFromReleasePrecondition if set to false.

SettingsDefaultOverrides documents the effect of several migrations that add an explicit value for a setting, effectively changing the "default value" from what was defined in code.