## 66.2. Built-in Operator Classes

The core PostgreSQL distribution includes the SP-GiST operator classes shown in Table 66.1.

Table 66.1. Built-in SP-GiST Operator Classes

Name | Indexed Data Type | Indexable Operators | Ordering Operators
--- | --- | --- | ---
`kd_point_ops` | `point` | `<<` `<@` `<^` `>>` `>^` `~=` | `<->`
`quad_point_ops` | `point` | `<<` `<@` `<^` `>>` `>^` `~=` | `<->`
`range_ops` | any range type | `&&` `&<` `&>` `-|-` `<<` `<@` `=` `>>` `@>` |
`box_ops` | `box` | `<<` `&<` `&&` `&>` `>>` `~=` `@>` `<@` `&<|` `<<|` `|>>` `|&>` |
`poly_ops` | `polygon` | `<<` `&<` `&&` `&>` `>>` `~=` `@>` `<@` `&<|` `<<|` `|>>` `|&>` | `<->`
`text_ops` | `text` | `<` `<=` `=` `>` `>=` `~<=~` `~<~` `~>=~` `~>~` `^@` |
`inet_ops` | `inet`, `cidr` | `&&` `>>` `>>=` `>` `>=` `<>` `<<` `<<=` `<` `<=` `=` |

Of the two operator classes for type `point`, `quad_point_ops` is the default. `kd_point_ops` supports the same operators but uses a different index data structure that may offer better performance in some applications.

The `quad_point_ops`, `kd_point_ops` and `poly_ops` operator classes support the `<->` ordering operator, which enables the k-nearest neighbor (`k-NN`) search over indexed point or polygon data sets.