An index column need not be just a column of the underlying table, but can be a function or scalar expression computed from one or more columns of the table. This feature is

Indexes can also be used to enforce uniqueness of a column's value, or the uniqueness of the combined values of more than one column.

Although indexes in PostgreSQL do not need maintenance or tuning, it is still important to check which indexes are actually used by the real-life

An index can be defined on more than one column of a table. For example, if you have a table of this form:

An index definition can specify an operator class for each column of an index.

All indexes in PostgreSQL are secondary indexes, meaning that each index is stored separately from the table's main

A single index scan can only use query clauses that use the index's columns with operators of its operator class and are joined with AND. For example

A partial index is an index built over a subset of a table; the subset is defined by a conditional expression (called the predicate

Suppose we have a table similar to this: CREATE TABLE test1 ( id integer, content

PostgreSQL provides several index types: B-tree, Hash, GiST, SP-GiST, GIN and BRIN. Each index type uses a different algorithm that is best