We're experiencing strange performance issues running:

• Zend Framework 2.3.3 on PHP 5.5.18-1
• Doctrine MongoDB ODM Module (https://github.com/doctrine/mongodb, https://github.com/doctrine/DoctrineMongoODMModule)
• Ubuntu 12.04 on VirtualBox via Vagrant (https://vagrantcloud.com/hashicorp/boxes/precise64)

We know for sure that this is not a DB issue (tried it with a real MongoDB instance, still same result).

---

Scenario

We have defined objects that work with Doctrine ODM in a manner similar to this:

<?php

namespace CatalogueManager\Document;

use Doctrine\ODM\MongoDB\Mapping\Annotations as ODM;
use Doctrine\Common\Collections\ArrayCollection;

/*
 * @ODM\Document(repositoryClass="CatalogueManager\Repository\ProductRepository")
 */
class Item
{
    /** @ODM\Id */
    protected $id;

    /** @ODM\String */
    protected $name;

    /** @ODM\Timestamp */
    protected $created;

    /** @ODM\Timestamp */
    protected $updated;

    // ---------------------------------------------------------------------- //

    /**
     * Return properties as an array. Helper method to assist with converting
     * doctrine objects to arrays so we can return front-end api calls as json.
     *
     * Required as currently Doctrine ODM do not support array hydration of
     * referenced documents.
     *
     * @access public
     * @return array
     *
     */
    public function toArray()
    {
        $arr = ['id'          => $this->id,
                'name'        => $this->name,
                'urlSlug'     => $this->urlSlug,
                'desc'        => $this->desc,
                'metaData'    => $this->metadata,
                'category'    => $this->category,
                'brand'       => $this->brand,
                'assets'      => $this->assets,
                'shipping'    => $this->shipping,
                'specs'       => $this->specs,
                'attrs'       => $this->attrs,
                'optionTypes' => $this->optionTypes
                ];

        return $arr;
    }

    // ---------------------------------------------------------------------- //

    /**
     * Getter
     *
     * @access public
     * @return string
     *
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * Getter
     *
     * @access public
     * @return string
     *
     */
    public function getName()
    {
        return $this->name;
    }

    // ---------------------------------------------------------------------- //

    /**
     * Setter
     *
     * @param string $value Property value
     *
     * @access public
     * @return void
     *
     */
    public function setName($value)
    {
        $this->name = $value;
    }

}

We're using these to import approx. 100 products into a product database. This all takes about 5 seconds on a real machine but when trying on a virtual machine, it takes approx. 25 seconds to do the same thing.

Looks like the problem could be Apache which is taking 99% load while this all is being processed, yet I'm having difficulty pinpointing what's really going on.

Any kind of advice would be appreciated...

---

Update

This only seems to occur when writing data. Reading data seems to be ok.

Webgrind data (screenshot) available: https://www.dropbox.com/s/jjlg7ano6epy6t1/webgrind.png?dl=0

After looking at some of your screenshots of XDebug data, I think you are simply using the ORM/ODM in the wrong way, since you are batch processing > 13K results.

The correct solution for this sort of operation is explained at http://doctrine-orm.readthedocs.org/en/latest/reference/batch-processing.html

What is happening is very simple: - the ODM loads one record from the DB - the ODM stores that record into the UnitOfWork - on flush, the ODM iterates over all entries in the UnitOfWork, looking for changed documents/entities

If you keep storing more data in the UnitOfWork, then obviously the iteration is going to take longer times at every repetition of the operation.

You should call ObjectManager#clear() between batch chunks being processed.