# Performance Settings
The performance group in the configuration tool controls the caching of data in SanteDB.
The services installed by default on SanteDB are:
* REDIS Based Caching Services: These connect to the REDIS server and store objects in cache there. REDIS caching is useful in a scaled-out deployment where multiple application servers must share cached data between themselves.
* Memory Based Caching Service: These are local in-process caches. This type of caching service is useful for single process or single application servers.
The caching control panel is broken into two sections:
* Configuration Sections: Which are used to control the configuration of each class of caching, and
* Services Section: Which is used to set the caching service/strategy used.
## Services Configuration
The services section is used to to control the implementations of the caching infrastructure.
| Option | Description | Example |
| -------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------- |
| Data Object Cache | The data object cache is used to store fully loaded objects from the database. This service reduces load on the database. | |
| Ad-Hoc Cache | The ad-hoc cache is used to store any value which a plugin needs to store. These are typically used to cache policy decisions, policy information, term lookups, etc. | |
| Stateful Query Cache | The stateful query cache is used to store stateful query results which are paginated on the client. Stateful queries are useful for freezing a result set to those at the time of query. | |
## Cache Configuration
### REDIS Configuration
| Option | Description | Example |
| ------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------- |
| REDIS Server(s) | The location of the REDIS server (or pool of servers) which should be used for caching. | `127.0.0.0:6729` |
| REDIS User | If the REDIS server requires authentication (recommended) the username to use to authenticate with the REDIS server. | |
| Password | If the REDIS server requires authentication (recommended) the password which matches the username. | |
| TTL | The Time To Live of objects stored in REDIS. Default is 15 minutes. | 00:15:00 15 Minutes
01:00:00 1 Hour
|
| Broadcast Messages | If true, then the SanteDB server will broadcast updates to the REDIS server cache objects so that other SanteDB servers are notified when data in the REDIS server changes. | |
### Memory Configuration
| Option | Description | Example |
| ------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------- |
| Max Cache Size (MB) | The maximum amount of in-process memory to dedicate to caching objects. | `1000` = 1 GB |
| Max Cache Age (S) | The maximum length of time in seconds for cached objects to live in the cache before being evicted. | |
| Max Query Age (S) | The maximum length of time (in seconds) for cached stateful queries to be retained before being evicted (note: callers must complete consumption of the query prior to this time) | |