Spent a few years using Spanner in production across fintech and payments systems. The SQL interface is familiar — tables, indexes, transactions, schemas. But that familiarity can be misleading. A lot of habits that work perfectly in traditional relational databases quietly become problems in Spanner. Some things I had to learn over the period of time Auto-increment keys that concentrate writes instead of distributing them Indexes that look harmless but create their own hotspots Transactions that are correct but touch too many unrelated key ranges Joins that work fine locally but need distributed coordination in Spanner submitted by /u/mathankumart [link] [comments]