Introduction

Caché eXTreme is a set of technologies that enable Caché to be leveraged as a high performance persistence storage engine optimized for XTP (Extreme Transaction Processing) applications.

Unlike the standard .NET binding, the eXTreme APIs do not use TCP/IP to communicate with Caché. Instead, they use a fast in-memory connection (implemented via standard .NET and the Caché Callin API), and run in the same process as the Caché instance. Although the Caché server and the .NET application must be on the same machine, the application can still use Caché ECP to access data on remote machines.

Caché eXTreme components include:

eXTreme Event Persistence (XEP) — allows simple .NET objects to be projected as XTP persistent events for rapid storage and processing. This is a lightweight API for low latency object and event stream data access (see “Using eXTreme Event Persistence”).

Installation and Configuration

This section provides specifies requirements and provides instructions for installing Caché and configuring your environment to use the eXTreme APIs.

Requirements

The .NET Framework, versions 2.0, 3.0, or 4.0.
Caché 2012.2 or higher.
The Caché User namespace must exist and must be writable if your application uses XEP (see “Using eXTreme Event Persistence”).

Installation

When installing Caché in Windows, select the Setup Type: Development option.
If Caché has been installed with security level 2, open the Management Portal and go to System Administration, Security, Services, select %Service_CallIn, and make sure the Service Enabled box is checked.
If you installed Caché with security level 1 (minimal) it should already be checked.

Required Environment Variables

In order to run eXTreme applications, the following environment variable must be properly set:

Your PATH environment variable must include <install-dir>/bin.
If your PATH variable includes more than one <install-dir>/bin path (for example, if you have installed more than one instance of Caché) only the first one will be used, and any others will be ignored.

Required Files

Your .NET project must include references to the following files:

InterSystems.CacheExtreme.dll — located in <install-dir>/dev/dotnet/bin/v2.0.50727
InterSystems.Data.CacheClient.dll — is provided in three different versions, one for each supported release of the .NET Framework. The different versions are located in appropriately named subdirectories of <install-dir>/dev/dotnet/bin (for example, <install-dir>/dev/dotnet/bin/v4.0.30319 contains the file for .NET 4.0). Use the appropriate file for the release that will be used to compile your project.

eXTreme Sample Applications

Sample applications are available for all eXTreme APIs.

XEP Samples

XEP sample files are in <install-dir>/dev/dotnet/samples/xep/ (see “Default Caché Installation Directory” for the location of <install-dir> on your system). To run them, compile the XEPTest40.csproj project, which includes the following components (located in subdirectory /xep/test/):

RunAll.cs — is a program that runs all of the other sample programs in sequence.
This program connects to Caché with a hard-coded superserver port value of 1972 (see “DefaultPort” in the Caché Parameter File Reference). If your system does not use this default value, change the port number in the first line of the program and recompile.
Coverage.cs — tests basic functionality such as connecting, importing a schema, storing, querying, updating and deleting XEP events. It also exercises most of the supported data types.
SingleString.cs — is the most basic XEP test program. It connects to the database, imports a simple class containing only one string field, then stores and loads a number of events corresponding to that class.
FlightLog.cs — is an example that demonstrates the XEP full inheritance model. It tracks airline flight information such as times, locations, personnel, and passengers.
Benchmark.cs — is a performance test for the XEP API.
IdKeys.cs — extends the Benchmark test by adding the composite IdKey feature.
Threads.cs — is a multithreaded XEP test program.

See the help file (<install-dir>/dev/dotnet/help/CacheExtreme.chm) for detailed documentation of these programs. Supporting files located in <install-dir>/dev/dotnet/samples/xep/samples/ provide test data for the sample programs. The xep.samples.SingleStringSample class is used by several examples in this book.