GiST and SP-GiST indexes can be created for table columns of the set and span types. The GiST index implements an R-tree while the SP-GiST index implements a quad-tree. An example of creation of a GiST index in a column During
of type tstzspan
in a table Reservation
is as follows:
CREATE TABLE Reservation (ReservationID integer PRIMARY KEY, RoomID integer, During tstzspan); CREATE INDEX Reservation_During_Idx ON Reservation USING GIST(During);
A GiST or an SP-GiST index can accelerate queries involving the following operators: =
, &&
, <@
, @>
, -|-
, <<
, >>
, &<
, &>
, <<#
, #>>
, &<#
, #&>
, and <->
.
In addition, B-tree indexes can be created for table columns of a set or span types. For these index types, basically the only useful operation is equality. There is a B-tree sort ordering defined for values of span time types with corresponding <
, <=
, >
, and >=
operators, but the ordering is rather arbitrary and not usually useful in the real world. The B-tree support is primarily meant to allow sorting internally in queries, rather than creation of actual indexes.
Finally, hash indexes can be created for table columns of a set or span types. For these types of indexes, the only operation defined is equality.