sequel-annotate annotates Sequel models with schema information. By default, it includes information on columns, indexes, and foreign key constraints for the current table. On PostgreSQL, this includes more advanced information, including check constraints, triggers, comments, and foreign keys constraints for other tables that reference the current table.

simple_recommender offers item-based similarity recommendations for a Rails app using Postgres, using your existing ActiveRecord associations

Manage delta indexes via Resque for Thinking Sphinx

This extension provides an interface for the admin to upload new themes, publish it to the spree store, modify the theme layout accordingly and later download it.

Provides easy DSL integration between ActiveAdmin & state_machine

Save unnecessary round trips to the database

An ActiveRecord plugin providing a higher-level abstraction for SQL 'LIKE' queries

Gives ActiveRecord support for PostgreSQL's native inherited tables

From http://edgeguides.rubyonrails.org/active_record_migrations.html#types-of-schema-dumps: There is however a trade-off: db/schema.rb cannot express database specific items such as triggers, stored procedures or check constraints. While in a migration you can execute custom SQL statements, the schema dumper cannot reconstitute those statements from the database. If you are using features like this, then you should set the schema format to :sql. No longer is this the case. You can now use the default schema format (:ruby) and still preserve your check constraints.

Support for Postgres Notify/Listen

This gem forwards to activerecord's default postgresql adapter

Amazon Redshift adapter for ActiveRecord 7+

An Active Record extension for Multitenancy with PostgreSQL Row Level Security

Automatic database view creation for ActiveRecord

PostgreSQL Adapter for Active Storage

ArelToolkit contains parsing, querying, modifying, optimisations, extensions and more for Arel.

Add support for PostgreSQL's SEQUENCE on ActiveRecord migrations

Access postgres without blocking.

Encryption at rest made easy

It can create postgresql dump from mysql database or directly load data from mysql to postgresql (at about 100 000 records per minute). Translates most data types and indexes.