> For the complete documentation index, see [llms.txt](https://crystal-garage.gitbook.io/lustra-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://crystal-garage.gitbook.io/lustra-docs/querying/the-collection-object/fetching-the-query/cursored-fetching.md).

# Cursored fetching

Normal fetching can load the full result set into memory.

For large result sets, use PostgreSQL cursor-based fetching.

## Model Cursor Fetching

`each_with_cursor` yields model instances in batches:

```crystal
User.query.each_with_cursor do |user|
  puts user.email
end
```

Set the batch size with the first argument:

```crystal
User.query.each_with_cursor(100) do |user|
  puts user.email
end
```

You can also pass `fetch_columns`:

```crystal
User.query
  .select("users.*", "LOWER(email) AS normalized_email")
  .each_with_cursor(500, fetch_columns: true) do |user|
    puts user["normalized_email"]
  end
```

## Raw Cursor Fetching

`fetch_with_cursor` yields raw result hashes:

```crystal
User.query.select("id", "email").fetch_with_cursor(count: 500) do |row|
  puts "#{row["id"]}: #{row["email"]}"
end
```

Cursor fetching runs inside a transaction because PostgreSQL cursors are transaction-scoped.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://crystal-garage.gitbook.io/lustra-docs/querying/the-collection-object/fetching-the-query/cursored-fetching.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.