This seems to be (with coincidental timing) the cause of Mandrill’s current outage [1]: > Mandrill uses a sharded Postgres setup as one of our main datastores.

This seems to be (with coincidental timing) the cause of Mandrill’s current outage [1]: > Mandrill uses a sharded Postgres setup as one of our main datastores. On Sunday, February 3, at 10:30pm EST, 1 of our 5 physical Postgres instances saw a significant spike in writes. The spike in writes triggered a Transaction ID Wraparound issue. When this occurs, database activity is completely halted. The database sets itself in read-only mode until offline maintenance (known as vacuuming) can occur. > The database is large—running the vacuum process takes a significant amount of time and resources, and there’s no clear way to track progress. [1] https://news.ycombinator.com/item?id=19084525 https://news.ycombinator.com/item?id=19084525