Changing The Engine While You’re Driving Down The Highway

In my day job, I’m the gatekeeper for changes to the company’s production databases. We recently ran into an interesting and difficult problem: how do we change a large, heavily-used table without violating our “avoid downtime if possible” mantra?

The following is a slightly expurgated version of the postmortem I sent the team. Table names have been changed to protect the guilty.

Read more »