![]() ![]() It can provide another view that something hasn’t been created properly during your diff run. Recommend that you turn on performance insights for RDS and watch that screen carefully. If you’ve done this as part of a cutover, you’re about to get a flood of users hitting your brand-new RDS database instance. By checking that all your indexes both exist and are valid first, you can save yourself some significant pain. ![]() Your CPU usage is going to get pegged at 100% and your application will fall to pieces. If you have queries that are unindexed and suddenly you have a surge of traffic. Re-creating these in the correct order will usually resolve your problems. Unusable indexes can come from things like primary keys indexes failing to create due to constraints or similar issues. You can use SQL Developer studio or SQL commands to investigate these indexes, drop them and recreate them before continuing. If you find indexes that have a status of “UNUSABLE” then you will need to investigate why before continuing! the following will help you identify the rows.Įnter fullscreen mode Exit fullscreen mode Out of almost 1 billion rows that we moved, we did experience 6 duplicate row issues across 3 tables due to us stopping and starting cdc a few times. If you are unable to apply constraints due to duplicate rows, the below will help you identify and remove these rows. Compare the details of the constraint, not just the name. Some standard constraints or SYS constraints with a different name, such as a constraint with a different name being enabled or disabled.Constraints may need to be applied in the correct order, for example.Įnsure that you are comfortable with the output here as we are nearing the end of this journey. Debug why these constraints aren’t working ahead of time and take note of resolutions. You should have done this a few times by now in nonprod/preprod. It’s possible not all constraints or indexes will create successfully, check the output of executed SQL carefully. If you feel like it has missed something, you can invert the disable commands in the above section. Running the output of the diff will enable constraints and enable triggers that were previously disabled. These are all safe to run, Oracle will complain if it can’t do something. Take note of any failures during execution and save that output to a separate file. Now you can run those against the Target DB in the following order, ensure you save all the output.į. ![]() ![]() Recommend that you separate your diff into the following filesĮ. If you see a lot of drop statements, check everything you’ve done so far.ĭ. Create or replace statements are fine, drop statements need more investigation. Check that you have all the tables you need from the source and your diff doesn’t want to create more tables, typically if you have old or legacy tables with 0 rows these may not need to be created in the Target.
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