Types of index scans Indexes Sequential Scan: Read every row in the table No reading of index. Reading from indexes is also expensive. Best way to access small tables, that fits in a single disk block. There is no point in this case to use the index. Block size in pg is 8K. Also the best way to read access all rows in a table. Index Scan: Index Scan or Bitmap Index Scan: Read the index, hoping that we won’t have to go to disk.