Duplicate entries on updateOrCreate

[chimit]

• Laravel Version: 5.4
• PHP Version: 7.1
• Database Driver & Version: MySQL 5.7

Description:

I want to save mobile devices information in the database using their UUIDs. The uuid field has a unique index. The code is:

$device = Device::updateOrCreate(
    ['uuid' => $request->input('uuid')],
    [
        'info' => $request->input('info'),
    ]
);

But I'm getting a lot of errors in logs:

Next Doctrine\DBAL\Driver\PDOException: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'aa18269c-cf32-4c6b-b450-e84a5dba0a0c' for key 'devices_device_uuid_unique' in /var/www/api/vendor/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOStatement.php:93
Stack trace:

I also tried to use firstOrNew:

$device = Device::firstOrNew(['uuid' => $request->input('uuid')]);
$device->info = $request->input('info');
$device->save();

But it's equal I guess.

If I remove the unique index from the uuid field the problem is gone but I get duplicate entries. That's strange because I thought updateOrCreate method guarantees uniqueness of the entries.

Is it a bug of the updateOrCreate method?

[Kyslik]

Whats your database structure, share migration for the table.

[srmklive]

Can you share your database structure or migration file for the table?

[chimit]

Schema::create('devices', function (Blueprint $table) {
    $table->increments('id');
    $table->integer('user_id')->unsigned()->nullable();
    $table->string('uuid')->unique();
    $table->timestamps();
});

[themsaid]

Since it happens on random occasions I believe it might be a race condition with the record is being created via another request in between the check and insert inside updateOrCreate().

[Reaper45]

Well. I think this is a Laravel mass assignment Issue.
When using the Eloquent create method, you will need to specify either a fillable or guarded attribute on the model, as all Eloquent models protect against mass-assignment by default. In your case @chimit: add this to your device.php model

public $fillable = ['uuid', 'info'];

I put the solution code here.

[chimit]

Hi @Reaper45!
I already have it in my Device model otherwise I would get Mass Assignment exceptions. The problem is that updateOrCreate method doesn't really guarantee what it was created for. Maybe this method should be improved, for example, using transactions.

[themsaid]

updateOrCreate method doesn't really guarantee what it was created for. Maybe this method should be improved, for example, using transactions.

Feel free to open a PR if you have a better idea, meanwhile I'm closing this since it's not actually a bug.

[alessandrolattao]

I am having the exact same problem.
If at least two requests happen simultaneously, updateOrCreate does not behave correctly.
You can easily reproduce the problem by using ab (apache bench) by using this command: ab -n 2 -c 2 http://your.url.here (I used a GET request for testing purpose).
This generates two simultaneous requests to the "update url" and lead eloquent to generate two insert queries.

[lk77]

i think you could use lock to prevent simultaneous calls.

Device::where(['uuid'` => $request->input('uuid')]->lock(true);
//your code
Device::where(['uuid' => $request->input('uuid')]->lock(false); 

or something like that i've not tested it.

[alessandrolattao]

Yes, I could.
But that would force me to add locks everywhere to handle updateOrCreate problems.
I think the function should be atomic. :)

[rajjanorkar]

this is still problem.

[didioh]

I solved this problem by overriding Illuminate\Database\Eloquent\Model and creating a custom firstOrCreate method that returns the model if there is a duplicate error exception. This should work for mySQL connections.

class SystemModel extends Illuminate\Database\Eloquent\Model
{
	/**
	* Check if Illuminate\Database\QueryException is Duplicate Entry Exception.
	*
	* @param  array  $attributes
	* @return \Illuminate\Database\Eloquent\Model
	*/
	protected function isDuplicateEntryException(Illuminate\Database\QueryException $e){
		$errorCode  = $e->errorInfo[1];
		if ($errorCode === 1062) { // Duplicate Entry error code
			return true;
		}
		return false;
	}

	/**
	* Get the first record matching the attributes or create it.
	*
	* @param  array  $attributes
	* @param  array  $values
	* @return \Illuminate\Database\Eloquent\Model
	*/
	public static function firstOrCreate(array $attributes, array $values = [])
	{
		try {    		
			$static = (new static);
			return $static->create($attributes + $values);
		} catch (Illuminate\Database\QueryException $e){
			if($static->isDuplicateEntryException($e)) {
				return $static->where($attributes)->first();
			}
		}
	}
}

[paulrrogers]

Please reopen this ticket. I'd agree with other commenters that this is an actual bug since it is surprising behavior for any moderately busy service where collisions are possible. While the implementation does not concern me the syntax implies it is somehow atomic.

This could be achieved in a variety of ways:

• upsert (syntax varies by DBMS)
• pessimistic locks ("SELECT ... FOR UPDATE")
• database transactions with at least one auto-retry
• partial mitigation with updated_at columns (typically needs sub-second precision).

In my opinion firstOrCreate also has this weakness and likely any ...OrCreate method.

All that said, I can see why the ...OrNew methods cannot be atomic since they only return unsaved, dirty objects. The others do not have that restriction.