Entity Framework Cache Provider
Entity Framework provides abstraction from the underlying relational data stored in a database and presents its conceptual schema to the application, preventing the need to write database persistence code.
Entity Framework can be seen in most of the high transaction applications where scalability and performance cannot be compromised. However, in such critical cases, the database quickly becomes a bottleneck as the database tier does not support adding on more servers. To achieve this scalability, NCache provides a pluggable in-memory cache provider to act as a second level cache and cache query results.
The upsides to using NCache as a Second Level Cache in Entity Framework applications are:
- No Code Change: NCache Entity Framework Caching Provider can be integrated in application without any code change.
- Better Performance: NCache custom provider intercepts all the database queries calls and caches the query result sets. This increases the performance of applications by avoiding expensive databases trips.
- Application Scalability: NCache provides a reliable and shared memory resource for storage. It gives the ability for sharing transactional context between different entities in any entity framework application.
The caching provider can perform various functions, such as:
- Managing connections, commands, transactions and data readers.
- Monitoring queries and commands before they execute.
The following figure shows how and where NCache Entity Framework Provider plugs into an Entity Framework application.
Entity Framework Caching Integration Modes
There are two execution modes for NCache Entity Framework Caching Provider:
- Analysis mode
- Caching mode
These modes are mutually exclusive, so NCache Entity Framework Caching Provider cannot execute in both modes at the same time. It can either be in "Caching" mode or in "Analysis" mode.
Recommendation: First execute the entity framework application within Analysis mode of NCache Entity Framework Caching Provider.
- Analysis Mode
Analysis mode is a pass-through mode; no caching is done at this mode. This mode provides features that are listed as follows:
Monitoring Query: Monitoring the number of times each query is executed by Entity Framework application. This allows the user to determine which queries are most frequent and the best candidates for caching.
Generate Reports: It generates reports for queries with proper syntax and also arranging them in descending order. That allows the user to choose suitable queries and copies them for caching.
<analysis-report> <!--Call-count = 21--> <query query-text="" ["SELECT FROM Products"] | [stored-procedure-name = ""] caching = "true" expiration-type="absolute" | sliding = "" expiration-time="180" dbsyncdependency = "true"/> </analysis-report>
- Caching Mode
This mode is basically designed for the actual use of NCache in Entity Framework applications. At this point, queries and their result sets are cached. Caching mode only entertains those queries which are given in configuration file i.e. efcaching.ncconf.
NCache Supported Features with Entity Framework
While NCache acts as a second level cache for EF applications, it provides the following features as well, which can be specified through the Entity Framework Caching config file:
Cache synchronization with database: In some cases, some data that is in the cache may be changed in the database without the application's involvement. Hence, you can specify the corresponding classes for database synchronization feature of NCache. This allows NCache to connect with the database, monitor data changes, and update the cache automatically to ensure that data in the cache is always synchronized with the database. NCache provides SqlDependency for SQL Server, OracleDependency for Oracle, and DbDependency for any OLEDB compliant databases.
Absolute Expiration: Absolute expiration is specified separately for each cached item and is a
DateTimevalue which specifies when NCache should automatically expire the item. For Entity Framework, NCache asks you to specify an "interval" value and then uses
Now() + intervalformula to calculate the date-time value for absolute expiration.
Sliding Expiration: Sliding expiration is specified separately for each cached item and is an interval value. NCache expires the cached item if it has neither been fetched nor updated for this interval.
Dynamic Compact Serialization: NCache allows you to register your Entity Framework classes for Compact Serialization and generates serialization code when your application connects to the cache. NCache dynamically compiles this code in-memory and uses it for serialization, thereby increasing the serialization performance.
In This Section
NCache as Entity Framework Second Level Cache
Explains how to configure and use NCache as Entity Framework second level cache.
Entity Framework-Caching Config File
Explains the changes required in EFcaching.ncconf to run the Entity Framework application in NCache.