# Bug in eager loading and polymorphic associations?

**URL:** <https://www.ruby-forum.com/t/bug-in-eager-loading-and-polymorphic-associations/135694>\
**Category:** Rails\
**Created:** [April 24, 2008, 9:51am UTC](https://www.ruby-forum.com/t/bug-in-eager-loading-and-polymorphic-associations/135694 "2008-04-24T09:51:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![rub3n](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/dec6dc/32.png) [@rub3n](https://www.ruby-forum.com/u/rub3n)\
**Post date:** [April 24, 2008, 9:51am UTC](https://www.ruby-forum.com/t/bug-in-eager-loading-and-polymorphic-associations/135694/1 "2008-04-24T09:51:06Z")

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Hi friends, i’m usgin the edge version because i need eager loading on  
polymorphic associations support, but i see this:

Message.find(:first, :include =\> :owner) #This generate this query:  
SQL (0.000072) SET SQL\_AUTO\_IS\_NULL=0  
Message Load (0.000389) SELECT \* FROM `messages`  
User Load (0.001070) SELECT \* FROM `users` WHERE (users.id IN  
(1,2))

And this Message.find(:first, :include =\> :owner, :limit =\> 1)  
generate this:  
Message Load (0.000460) SELECT \* FROM `messages` LIMIT 1  
User Load (0.000318) SELECT \* FROM `users` WHERE (users.id IN (2))

Both querys return me the correct owner of message, but in the first  
query AR fetch an aditional record, anyboby know why?

Thanks.

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<div class="post-metadata">

**Author:** ![rub3n](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/dec6dc/32.png) [@rub3n](https://www.ruby-forum.com/u/rub3n)\
**Post date:** [April 24, 2008, 9:56am UTC](https://www.ruby-forum.com/t/bug-in-eager-loading-and-polymorphic-associations/135694/2 "2008-04-24T09:56:59Z")

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Fdavila wrote:

> Hi friends, i’m usgin the edge version because i need eager loading on  
> polymorphic associations support, but i see this:

[snip]

Well in the first case it seems to have ignored your :first. It’s  
probably a bug.

Fred

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<div class="post-metadata">

**Author:** ![rub3n](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/dec6dc/32.png) [@rub3n](https://www.ruby-forum.com/u/rub3n)\
**Post date:** [April 27, 2008, 12:51pm UTC](https://www.ruby-forum.com/t/bug-in-eager-loading-and-polymorphic-associations/135694/3 "2008-04-27T12:51:43Z")

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Turns out that this was something that has been lurking for a long  
time. it’s fixed now  
([Changeset: Changeset [361aaa04ef2f33cb1fe49497c73bc13e6b72addc] by Aliaksey Kandratsenka - Ruby on Rails - rails](http://rails.lighthouseapp.com/projects/8994/changesets/361aaa04ef2f33cb1fe49497c73bc13e6b72addc)  
)