How We Achieved Minimal Downtime During Our PostgreSQL Database Upgrade (English Version)

Hello everyone, I’m Kenny, a Backend Engineer from Dcard.
Dcard is a social networking platform that allows everyone to share ideas with confidence, regardless of background, age, or interest. It is Taiwan’s largest anonymous communication platform.
Recently, we upgraded the primary PG 9.6 Cluster of Dcard’s services to the 11 version, managing to limit write downtime within ten minutes, and successfully rebuilt the OfflineDB and CDC services within an hour. In this article, we will share how we accomplished this challenging task.