He wonders about PostgreSQL users doing poorly on question 4. This is a fairly tricky question. Since the index is a btree index, it is pretty clear what the

He wonders about PostgreSQL users doing poorly on question 4. This is a fairly tricky question. Since the index is a btree index, it is pretty clear what the right answer is, but there are ways to address the wildcard issue with better indexes. PostgreSQL folks who have less familiarity with the db may miss the fact that a GIN or GIST index is required along with the pg_trgm addon, to make that query fast.