Doctrine_manual-1-2-en

Chapter 28: Improving Performance 365
$results = $q->execute(array(), Doctrine_Core::HYDRATE_NONE);
You will need to print the results and find the value in the array depending on your DQL
query:
print_r($results);
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In this example the result would be accessible with the following code:
$total = $results[0][1];
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There are two important differences between HYDRATE_ARRAY and HYDRATE_NONE which
you should consider before choosing which to use. HYDRATE_NONE is the fastest but the
result is an array with numeric keys and so results would be referenced as
$result[0][0] instead of $result[0]['my_field'] with HYDRATE_ARRAY. Best
practice would to use HYDRATE_NONE when retrieving large record sets or when doing
many similar queries. Otherwise, HYDRATE_ARRAY is more comfortable and should be
preferred.
Bundle your Class Files
When using Doctrine or any other large OO library or framework the number of files that
need to be included on a regular HTTP request rises significantly. 50-100 includes per
request are not uncommon. This has a significant performance impact because it results in a
lot of disk operations. While this is generally no issue in a dev environment, it's not suited for
production. The recommended way to handle this problem is to bundle the most-used classes
of your libraries into a single file for production, stripping out any unnecessary whitespaces,
linebreaks and comments. This way you get a significant performance improvement even
without a bytecode cache (see next section). The best way to create such a bundle is probably
as part of an automated build process i.e. with Phing.
Use a Bytecode Cache
A bytecode cache like APC will cache the bytecode that is generated by php prior to executing
it. That means that the parsing of a file and the creation of the bytecode happens only once
and not on every request. This is especially useful when using large libraries and/or
frameworks. Together with file bundling for production this should give you a significant
performance improvement. To get the most out of a bytecode cache you should contact the
manual pages since most of these caches have a lot of configuration options which you can
tweak to optimize the cache to your needs.
Free Objects
As of version 5.2.5, PHP is not able to garbage collect object graphs that have circular
references, e.g. Parent has a reference to Child which has a reference to Parent. Since many
doctrine model objects have such relations, PHP will not free their memory even when the
objects go out of scope.
For most PHP applications, this problem is of little consequence, since PHP scripts tend to be
short-lived. Longer-lived scripts, e.g. bulk data importers and exporters, can run out of
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