Different types of Index in PostgreSQL

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This is part two of our PostgreSQL optimization series. You can read the first article where we discuss when to index here.

PostgreSQL uses a different set of algorithm while indexing tables, each type of algorithm is good for a certain set of data. Here we will be discussing the various algorithms available and when we should be using them. (Note these are the algorithms found in PostgreSQL 9.5)


B-Tree (Balance Tree), is the default algorithm used when we build indexes in Rails. It keeps a sorted copy of our column, which would be our index. So if we want to find the row of the word starting with a then as soon as the words starting with a are over. It will stop searching and return null, as the index has kept everything sorted. It is good in most cases, hence it is the default algorithm used.

Hash is one of the most popular indexing algorithms. But only the equate operator works on it, thus the query planner will only use an index with a hash algorithm if we do an equal operation searching for it. Another point to …

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Optimising PostgreSQL database query using indexes

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At Red Panthers PostgreSQL is our go to database we use it everywhere. So thinking about how to optimize our database performance is one of the most talked about topic at our office. The best way to speed up report generation and data retrieval within a rails application is to leave it to the database, as they have algorithms and optimizations build just for that. We always felt that most Ruby on Rails projects out there, do not use the full potential of a database and they usually just limit it to a data store. PostgreSQL or any database for that matter is much more than that.

We would be blogging on how we use PostgreSQL in our projects to speed up our client’s applications. This particle is the first part of a series of article we would be writing on database optimization.

Database Indexes:

Indexes are a special lookup table that the database search engine can use to speed up data retrieval. An Index is similar to a pointer to a particular row of a table. As a real world example, consider a Britannica Encyclopedia with 22 volumes of books, and an extra book listing  the index,with which …

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