How to implement cursor pagination in a Rails API?

Add the gem to your Gemfile, run bundle install, then use the cursor_paginate method on ActiveRecord relations. For example, Post.cursor_paginate(order: :created_at) fetches the first page with encoded cursors for stable navigation.

Cursor pagination vs offset pagination in Rails: which is better?

Cursor pagination is better for large, dynamic datasets (e.g., APIs, infinite scroll) as it prevents result jumps when data changes. Offset pagination is simpler for small, static data but can be unstable and slower with offsets.

How to order by multiple columns with ActiveRecordCursorPaginate?

Pass an array or hash to the order parameter, e.g., order: [:author, :title] for ascending, or order: { author: :asc, title: :desc }. The gem appends the primary key for uniqueness unless you set append_primary_key: false.

Can I use cursor pagination with joined tables in Rails?

Yes, but you must specify fully qualified column names and wrap custom SQL in Arel.sql, e.g., order: Arel.sql('projects.id'). Ensure proper indexing on the joined columns for performance.

What database indexes are needed for optimal performance?

For custom order columns, add compound indexes on (order_column, id). For example, if ordering by email, create an index on (email, id) in MySQL or PostgreSQL, as shown in the README migration example.

How to handle NULL values in order columns with this gem?

The README doesn't specify, but cursor pagination can struggle with NULLs. Consider using COALESCE in custom SQL expressions (e.g., Arel.sql('COALESCE(column, default_value)')) or ensure your database handles NULLs consistently in indexes.

activerecord_cursor_paginate — ActiveRecord Cursor Pagination

What is activerecord_cursor_paginate?

ActiveRecordCursorPaginate is a Ruby gem that adds cursor-based pagination to ActiveRecord relations. It solves the problem of unstable pagination in traditional offset/limit approaches by using encoded cursors that uniquely identify records, ensuring consistent results even when data changes between page requests.

Target Audience

Ruby on Rails developers building applications that require efficient, stable pagination through large or frequently updated datasets, such as APIs, dashboards, or data-intensive features.

Value Proposition

Developers choose this gem for its robust handling of dynamic data, support for custom ordering, and performance optimizations through proper indexing, making it a reliable alternative to offset-based pagination in ActiveRecord.

Cursor-based pagination for ActiveRecord

Use Cases

Best For

Building APIs that require stable pagination for mobile or web clients
Paginating large datasets where offset/limit performance degrades
Implementing infinite scroll features in Rails applications
Handling real-time data feeds where records are frequently added or deleted
Ordering results by non-ID columns (e.g., name, date) with pagination
Creating bidirectional pagination (next/previous) in ActiveRecord queries

Not Ideal For

Legacy Rails applications stuck on Ruby <2.7 or Rails <7.0, as the gem only supports newer versions.
APIs that must maintain compatibility with clients expecting traditional offset-based pagination (e.g., page numbers).
Projects with frequently changing order columns where index maintenance becomes cumbersome and impractical.
Simple CRUD applications with small, static datasets where the overhead of cursor pagination and indexing offers minimal benefit.

Pros & Cons

Pros

Stable Dynamic Pagination

Uses encoded cursors to uniquely identify rows, preventing result jumps when records are added or deleted during pagination, as detailed in the 'How does it work?' section.

Flexible Ordering Support

Allows ordering by any column, multiple columns, or custom SQL expressions via Arel.sql, with implicit primary key appending for uniqueness unless disabled.

Bidirectional Page Navigation

Supports forward pagination with 'after' cursors and backward pagination with 'before' cursors, enabling easy iteration over pages in both directions.

Performance with Indexing

Leverages database indexes for ordered columns; the README provides clear examples for adding compound indexes (e.g., on author and id) to optimize query efficiency.

Cons

Mandatory Indexing Overhead

Requires adding specific database indexes for custom order columns to maintain performance, which adds complexity to schema management and migrations.

Limited Backward Compatibility

Only supports Ruby 2.7+ and Rails 7.0+, excluding teams on older versions without a straightforward upgrade path mentioned in the README.

Complex Setup for Advanced Use

Ordering by JOINed columns or custom SQL expressions requires manual SQL qualification and Arel.sql wrapping, increasing the risk of errors and potential performance degradation if not indexed properly.

Frequently Asked Questions

What is activerecord_cursor_paginate?

Target Audience

Ruby on Rails developers building applications that require efficient, stable pagination through large or frequently updated datasets, such as APIs, dashboards, or data-intensive features.

Value Proposition

Use Cases

Best For

Building APIs that require stable pagination for mobile or web clients
Paginating large datasets where offset/limit performance degrades
Implementing infinite scroll features in Rails applications
Handling real-time data feeds where records are frequently added or deleted
Ordering results by non-ID columns (e.g., name, date) with pagination
Creating bidirectional pagination (next/previous) in ActiveRecord queries

Not Ideal For

Legacy Rails applications stuck on Ruby <2.7 or Rails <7.0, as the gem only supports newer versions.
APIs that must maintain compatibility with clients expecting traditional offset-based pagination (e.g., page numbers).
Projects with frequently changing order columns where index maintenance becomes cumbersome and impractical.
Simple CRUD applications with small, static datasets where the overhead of cursor pagination and indexing offers minimal benefit.

Pros & Cons

Pros

Stable Dynamic Pagination

Uses encoded cursors to uniquely identify rows, preventing result jumps when records are added or deleted during pagination, as detailed in the 'How does it work?' section.

Flexible Ordering Support

Allows ordering by any column, multiple columns, or custom SQL expressions via Arel.sql, with implicit primary key appending for uniqueness unless disabled.

Bidirectional Page Navigation

Supports forward pagination with 'after' cursors and backward pagination with 'before' cursors, enabling easy iteration over pages in both directions.

Performance with Indexing

Leverages database indexes for ordered columns; the README provides clear examples for adding compound indexes (e.g., on author and id) to optimize query efficiency.

Cons

Mandatory Indexing Overhead

Requires adding specific database indexes for custom order columns to maintain performance, which adds complexity to schema management and migrations.

Limited Backward Compatibility

Only supports Ruby 2.7+ and Rails 7.0+, excluding teams on older versions without a straightforward upgrade path mentioned in the README.

Complex Setup for Advanced Use

Frequently Asked Questions

activerecord_cursor_paginate

What is activerecord_cursor_paginate?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?

activerecord_cursor_paginate

What is activerecord_cursor_paginate?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?