<ul><li>PostgreSQL has an internal 1600 column limit that affects the addition and dropping of columns.</li><li>Adding a column without a default value is instantaneous and only updates system catalogs.</li><li>Dropping a column marks it as dropped in catalogs, but the physical data still exists in table tuples.</li><li>When the number of dropped columns reaches the limit, new schema changes are blocked until a full table rewrite is performed.</li></ul>

# PostgreSQL Tutorial: 📚 What Really Happens When You Add and Drop Columns 2000 Times in PostgreSQL

Discover more