Depends on the operation. For most operations there are backwards compatible options that generally result in a 2-step process.
Soundcloud (I don't work there) developed something in Ruby for online database migrations that copies the table and uses triggers to handle everything. Note that this only works for MySQL. For PostgreSQL or others, the best option is taking a backwards compatible approach.
I worked multiple years in an organization led by the founding team. Just dropping a note to say that the team is top-notch, and they are maniacal about listening to customer feedback.
They advocated for and implemented a strikingly similar product within the organization, and it was used for all deployments: development, test, staging, production, etc. The system was a crucial aspect of everyday development and extraordinarily helpful for working with cross-functional partners.
The order of magnitude is important. In your example it's a windfall. But considering the dilution with exits at 1b or 10b it's a different story - the exit will surely be millions.
The strategy should differ based on the role and company, as well as your years of experience and accomplishments. I doubt there's a one size fits all approach.
CV: Experienced in building technology for the financial sector. Have built and maintained payments processing software that does $80mm in annual revenue. E-mail me for my CV.
Soundcloud (I don't work there) developed something in Ruby for online database migrations that copies the table and uses triggers to handle everything. Note that this only works for MySQL. For PostgreSQL or others, the best option is taking a backwards compatible approach.
https://github.com/soundcloud/lhm