CREATE INDEX CONCURRENTLY implementation details
From the very beginning of 2021, I'm fixing a bug in CREATE INDEX CONCURRENTLY. This bug manifests extremely seldom. I could not find any traces of it in mailing lists ever since the introduction of the feature in 8.2. Yet the bug affected our systems, so I decided to fix it. This is how the9i detective bug-hunting story started. In this story, I'll share details of the implementation of transactions and lock mechanics.