Unique Constraint Violation Magento 2

Question

Very occasionally after a successful checkout the following error shows up on success page / logs:

 SagePaySuiteLogger.Exception: Unique constraint violation found

I am using Ebizmarts Sage pay suite 1.2.4 with form integration and Magento 2.2.3 although believe have had the issue for other versions also. I am guessing this is a duplicate entry somehow however hoping for any additional information about what this may be caused by or how to fix.

Trace:

[2018-03-29 08:26:44] SagePaySuiteLogger.Exception: Unique constraint violation found
#0 /home/sites/magento/public_html/vendor/magento/framework/Model/AbstractModel.php(647): Magento\Framework\Model\ResourceModel\Db\AbstractDb->save(Object(Magento\Sales\Model\Order\Payment\Transaction))
#1 /home/sites/magento/public_html/vendor/ebizmarts/sagepaysuite/Model/OrderUpdateOnCallback.php(72): Magento\Framework\Model\AbstractModel->save()
#2 /home/sites/magento/public_html/vendor/ebizmarts/sagepaysuite/Controller/Form/Success.php(172): Ebizmarts\SagePaySuite\Model\OrderUpdateOnCallback->confirmPayment('B1B897CC-D94C-4...')
#3 /home/sites/magento/public_html/vendor/magento/framework/App/Action/Action.php(107): Ebizmarts\SagePaySuite\Controller\Form\Success->execute()
#4 /home/sites/magento/public_html/vendor/magento/framework/Interception/Interceptor.php(58): Magento\Framework\App\Action\Action->dispatch(Object(Magento\Framework\App\Request\Http))
#5 /home/sites/magento/public_html/vendor/magento/framework/Interception/Interceptor.php(138): Ebizmarts\SagePaySuite\Controller\Form\Success\Interceptor->___callParent('dispatch', Array)
#6 /home/sites/magento/public_html/vendor/magento/framework/Interception/Interceptor.php(153): Ebizmarts\SagePaySuite\Controller\Form\Success\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
#7 /home/sites/magento/public_html/generated/code/Ebizmarts/SagePaySuite/Controller/Form/Success/Interceptor.php(26): Ebizmarts\SagePaySuite\Controller\Form\Success\Interceptor->___callPlugins('dispatch', Array, Array)
#8 /home/sites/magento/public_html/vendor/magento/framework/App/FrontController.php(55): Ebizmarts\SagePaySuite\Controller\Form\Success\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))
#9 /home/sites/magento/public_html/vendor/magento/framework/Interception/Interceptor.php(58): Magento\Framework\App\FrontController->dispatch(Object(Magento\Framework\App\Request\Http))
#10 /home/sites/magento/public_html/vendor/magento/framework/Interception/Interceptor.php(138): Magento\Framework\App\FrontController\Interceptor->___callParent('dispatch', Array)
#11 /home/sites/magento/public_html/vendor/magento/module-store/App/FrontController/Plugin/RequestPreprocessor.php(94): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
#12 /home/sites/magento/public_html/vendor/magento/framework/Interception/Interceptor.php(135): Magento\Store\App\FrontController\Plugin\RequestPreprocessor->aroundDispatch(Object(Magento\Framework\App\FrontController\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
#13 /home/sites/magento/public_html/vendor/magento/module-page-cache/Model/App/FrontController/BuiltinPlugin.php(73): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
#14 /home/sites/magento/public_html/vendor/magento/framework/Interception/Interceptor.php(135): Magento\PageCache\Model\App\FrontController\BuiltinPlugin->aroundDispatch(Object(Magento\Framework\App\FrontController\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))
#15 /home/sites/magento/public_html/vendor/magento/framework/Interception/Interceptor.php(153): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))
#16 /home/sites/magento/public_html/generated/code/Magento/Framework/App/FrontController/Interceptor.php(26): Magento\Framework\App\FrontController\Interceptor->___callPlugins('dispatch', Array, NULL)
#17 /home/sites/magento/public_html/vendor/magento/framework/App/Http.php(135): Magento\Framework\App\FrontController\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))
#18 /home/sites/magento/public_html/vendor/magento/framework/App/Bootstrap.php(256): Magento\Framework\App\Http->launch()
#19 /home/sites/magento/public_html/pub/index.php(37): Magento\Framework\App\Bootstrap->run(Object(Magento\Framework\App\Http\Interceptor))
#20 {main}

Code:

This is thrown it seems in the below code:

try {
    if (!$this->isModified($object)) {
        $this->processNotModifiedSave($object);
        $this->commit();
        $object->setHasDataChanges(false);
        return $this;
    }
    $object->validateBeforeSave();
    $object->beforeSave();
    if ($object->isSaveAllowed()) {
        $this->_serializeFields($object);
        $this->_beforeSave($object);
        $this->_checkUnique($object);
        $this->objectRelationProcessor->validateDataIntegrity($this->getMainTable(), $object->getData());
        if ($this->isObjectNotNew($object)) {
            $this->updateObject($object);
        } else {
            $this->saveNewObject($object);
        }
        $this->unserializeFields($object);
        $this->processAfterSaves($object);
    }
    $this->addCommitCallback([$object, 'afterCommitCallback'])->commit();
    $object->setHasDataChanges(false);
} catch (DuplicateException $e) {
    $this->rollBack();
    $object->setHasDataChanges(true);
    throw new AlreadyExistsException(new Phrase('Unique constraint violation found'), $e);
} catch (\Exception $e) {
    $this->rollBack();
    $object->setHasDataChanges(true);
    throw $e;
}

What does this error mean and how could i fix/debug my magento instance so this no longer occurs?

Answer 1

It may be because of the issue with orders related database entry like for example with the order increment id in main order table. Suppose a case where system tries to enter next order increment id 100000001 and if 100000001 is already available in the order table, then this issue will come.