What is SQL Server tempdb architecture and modern best practices?

tempdb is a shared system database used for temporary objects, versioning, and internal operations.

tempdb stores temporary tables, table variables, work tables, and row versioning data. It is recreated at startup, so no persistence exists. Performance issues arise due to allocation contention, large version store, and spills. Best practices include multiple data files, uniform sizing, and fast storage (SSD/NVMe).