Ranjan Marathe Blog

TIL: Microsoft SQL Server Sparse Columns

  1. Storage Efficiency: Saves space for columns with lots of NULLs.
  2. Cost-Effective: Lowers disk usage & I/O.
  3. Wide Tables: Regular limit is 1024 columns; with sparse, up to 30,000.
  4. Performance: Boosts reads for sparse data; minor overhead on non-NULLs.
  5. Column Sets: Group sparse columns into one XML column for easier access.
  6. Microsoft SQL Server: The only major RDBMS with native sparse column support. Comparable Concepts:
  7. NoSQL: Cassandra/HBase use dynamic, inherently sparse schemas.
  8. Other RDBMS: PostgreSQL (via JSONB/hstore) and Oracle (with compression techniques) can mimic sparse storage, but lack a direct sparse column feature.