CODEWITHSUNDEEP
mysqlruby-on-railsrubyactiverecord
Sandy W
Sandy W

Reputation: 356

Rails: ActiveRecord::UnknownPrimaryKey exception

A ActiveRecord::UnknownPrimaryKey occurred in survey_response#create:

Unknown primary key for table question_responses in model QuestionResponse.
activerecord (3.2.8) lib/active_record/reflection.rb:366:in `primary_key'

Our application has been raising these exceptions and we do not know what is causing them. The exception happens in both production and test environments, but it is not reproducible in either. It seems to have some relation to server load, but even in times of peak loads some of the requests still complete successfully. The app (both production and test environments) is Rails 3.2.8, ruby 1.9.3-p194 using MySQL with the mysql2 gem. Production is Ubuntu and dev/test is OS X. The app is running under Phusion Passenger in production.

Here is a sample stack trace: https://gist.github.com/4068400
Here are the two models in question, the controller and the output of "desc question_responses;": https://gist.github.com/4b3667a6896b60383dc3
It most definitely has a primary key, which is a standard rails 'id' column.

Restarting the app server temporarily stops the exceptions from occurring, otherwise they happen over a period of time 30 minutes - 6 hours in length, starting as suddenly as they stop.

It always occurs on the same controller action, table and model.

Has anyone else run into this exception?

Upvotes: 2

Views: 3954

Answers (4)

Mike Campbell
Mike Campbell

Reputation: 7978

FWIW, I was getting this same intermittent error and after a heck of a lot of head-scratching I found the cause.

We have separate DBs per client, and some how one of the client's DBs had a missing primary key on the users table. This meant that when that client accessed our site, Rails updated it's in-memory schema to that of the database it had connected to, with the missing primary key. Any future requests served by that Passenger app process (or any others that had been 'infected' by this client) which tried to access the users table borked out with the primary key error, regardless of whether that particular database had a primary key.

In the end a fairly self-explanatory error, but difficult to pin down when you've got 500+ databases and only one of them was causing the problem, and it was intermittent.

Upvotes: 3

montrealmike
montrealmike

Reputation: 11641

on postgres database

ALTER TABLE indices ALTER COLUMN id SET DATA TYPE INT;
ALTER TABLE indices ADD PRIMARY KEY (id)

Upvotes: 0

kashahkashah
kashahkashah

Reputation: 777

This same thing happened to me. I had a composite primary key in one of my table definitions which caused the error. It was further compounded because annotate models did not (but will shortly / does now) support annotation of composite primary keys.

My solution was to make the id column the only primary key and add a constraint (not shown) for the composition. To do this you need to drop auto_increment on id if this is set, drop your composite primary key, then re-add both the primary status and autoincrement.

ALTER TABLE indices MODIFY id INT NOT NULL;
ALTER TABLE indices DROP PRIMARY KEY;
ALTER TABLE indices MODIFY id INT NOT NULL PRIMARY KEY AUTO_INCREMENT;

Upvotes: 0

Alex Gusev
Alex Gusev

Reputation: 491

Got this problem because my workers used shared connection to database. But I was on unicorn.

I know that Passenger reconnects by default, but maybe you have some complicated logic. Connections to number of databases, for example. So you need to reconnect all connections.

Upvotes: 1

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