Performance

When it comes to performance, there are two distinct sections when using PINQ.

In memory queries

When utilising either the Traversable or Collection the queries are performed in memory, there should be little overhead from these operations. Obviously, if the data set was absurdly large, you could run into issues. But for most uses cases, you may actually incur a performance benefit, due to lazy evaluation and efficient iterator use.

External queries

For either Queryable or Repository, there is cause for concern. When querying these implementations, to accurately interpret them, the supplied functions will parsed into expression trees. This is a very expensive process and can incur a significant performance penalties if not setup correctly.

Caching parsed queries

To combat this, there are several options provided. Configuring the Pinq\Caching\CacheProvider class to set up the default caching mechanisms:

• File Cache - Caches the data in a single file, this is not optimal for high concurrency but is suited to those without access to a proper memory cache.

\Pinq\Caching\CacheProvider::setFileCache($filePath);

• Directory Cache - Caches the data in multiple files of a directory, while this may be relatively better for concurrency, is not very performant and a proper memory cache should be prefered.

\Pinq\Caching\CacheProvider::setDirectoryCache($directoryPath);

• Doctrine Cache - This allows you to use any cache from the Doctrine\Cache component,

\Pinq\Caching\CacheProvider::setDoctrineCache($cacheImplementation);

• Array Access Cache - This allows you to use any cache that implements ArrayAccess

\Pinq\Caching\CacheProvider::setArrayAccessCache($cacheImplementation);

• Custom Cache - Allows any cache implementing Pinq\Caching\ICacheAdapter

\Pinq\Caching\CacheProvider::setCustomCache($cacheImplementation);

All of the above options will significantly reduce the performance penalties by removing the need to parse the queries on every request. A proper memory cache such as Memcache or Redis using the Doctrine\Cache component should be preferred but the alternative file/directory cache should be sufficient for small applications and only requires disk access rather than the hassle of setting up a real cache.

During Development

Using a cache during development can be problematic as when queries are changed, they may be ignored and continue to use the original version. So during the development phase you should use:

\Pinq\Caching\CacheProvider::setDevelopmentMode(true);

When this flag it set to true, the cache will be cleared upon every request. But please remember to disable this before going into production.