Two early databases I worked on
Two early databases I worked on. The first contained monetary values. These were split over two columns, a decimal column holding the magnitude of the value, and a string column, containing an ISO currency code. Sounds good so far, right? Well, I learned much later (after, of course, having relied on the data) that the currency code column had only been added after expanding into Europe … but not before expanding into Canada. So when it had been added, there had been mixed USD/CAD values, but no currency code column to distinguish them. But when the column was added, they just defaulted it all to USD. So and USD value could be CAD — you "just" needed to parse the address column to find out. Another one was a pair of Postgres DBs. To provide "redundancy" in case of an outage, there were two such databases. But no sort of Postgres replication strategy was used between them, rather, IIRC, the client did the replication. There was no formal specification of the consensus logic — if it could even be said to have such logic; I think it was just "try both, hope for the best". …
Original discussion"We ran out of columns"571 source comments · at import