Types of Indexes

PostgreSQL supports various types of indexes, each tailored to specific use cases:

B-Tree Index

This is the default index type in PostgreSQL and is well-suited for most scenarios. It organizes data in a balanced tree structure, facilitating efficient range queries and equality checks. In particular, the PostgreSQL query planner will consider using a B-tree index whenever an indexed column is involved in a comparison using one of these operators:

<   <=   =   >=   >

Hash Index

Ideal for exact match queries, hash indexes employ a hash function to map keys to index entries. While they offer fast retrieval for equality conditions, they may not perform well with range queries or sorting.

This supports indexed queries using these operators:

=

GiST (Generalized Search Tree) Index

GiST indexes are versatile and support a wide range of data types and search operations. They are particularly useful for spatial and full-text search queries.

This supports indexed queries using these operators:

<<   &<   &>   >>   <<|   &<|   |&>   |>>   @>   <@   ~=   &&

GIN (Generalized Inverted Index) Index

GIN indexes are designed for handling complex data types such as arrays and full-text searches. They are optimized for fast search operations but may incur higher storage overhead compared to other index types.

This supports indexed queries using these operators:

<@   @>   =   &&

BRIN (Block Range Index) Index

BRIN indexes are suitable for large tables with ordered data. They divide the table into blocks and store summarized information for each block, making them efficient for range queries on sorted data.

This supports indexed queries using these operators:

<   <=   =   >=   >

In relational databases, PostgreSQL is recognized as one of the most reliable database management systems which is used for many web applications, mobile, and analytics applications. Indexing is one of the most important aspects that has a lot to do with the efficiency of the database.

In this article, we focus on indexes in PostgreSQL, explain their significance, examine their types, learn how to create them and discuss ways of optimization.