In Oracle Database 23ai, the Oracle RAC two-stage rolling patch provides a framework where such patches that include data dictionary changes can be applied in a rolling fashion and enabled after the patch has been applied to the last instance without requiring downtime to apply a patch.
This feature splits the patching operation between applying binary changes at the software level and SQL changes at the database level. During phase 1, patch is applied to all instances, but the fix is not enabled. When you look at the example in the slide, the example shows a full node RAC database, where 23.3.1 software version is installed across all four nodes.
When you apply patches with Oracle RAC two-stage rolling patch strategy, we apply patch one node at a time. While patches are being applied in a node, all the other instances running in the remaining servers still can access the Oracle Database because patch will be applied. However, until patch is applied in the last node, the fix is not enabled, thus users can access the database.
So we’re going to apply patch in the first node first. So users disconnected and user can reconnect to one of the three surviving and remaining servers. And once the patch is applied, the user can reconnect to database instance running on instance 1. And by doing so we can apply patches at software level in the second server and also third server and the first server.
On completion of phase 1, fix is enabled through SQL statement. So we’re going to run alter system enable rac two_stage rolling update all. So before running this command, the binary that is activated is a 23.3.1 even after the patch is applied. But after you run all the system enable rac two_stage rolling update all, this is the time when the fix is enabled.
So this software version is updated. So this feature helps to reduce the planned downtime. Reducing the need to take the database instance down also improves the performance as the workloads are not subject to rewarming the cache after instance restart. So this is a nice feature. The feature significantly reduces the number of nonrolling patches.
Recent Comments