> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/gridgain/gridgain-8/gridgain8-development/caches-and-memory/configuring-caches/configuration-overview.md).
# Cache Configuration
How to set GridGain cache configuration parameters, with a configuration example, the full parameter reference, and cache templates.
This chapter explains how you can set cache configuration parameters. Once a cache is created, you cannot change its configuration parameters.
## Configuration Example
Below is an example of a cache configuration.
{% tabs %}
{% tab title="XML" %}
```xml
```
For the full list of parameters, refer to the `CacheConfiguration` javadoc.
| Parameter | Description | Default Value |
| -------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- |
| `name` | The cache name. | None. |
| `cacheMode` | The cacheMode parameter defines the way data is distributed in the cluster.
In the PARTITIONED mode (default), the overall data set is divided into partitions and all partitions are split between participating nodes in a balanced manner.
In the REPLICATED mode, all the data is replicated to every node in the cluster.
See the Partitioned/Replicated Mode section for more details.
| `PARTITIONED` |
| `writeSynchronizationMode` | Write synchronization mode. Refer to the [Configuring Partition Backups](/docs/gridgain/gridgain-8/gridgain8-development/caches-and-memory/configuring-caches/configuring-backups.md) section. | `PRIMARY_SYNC` |
| `rebalanceMode` | This parameter controls the way the rebalancing process is performed. Possible values include:
SYNC -- Any requests to the cache's API are blocked until rebalancing is completed.
ASYNC (default) -- Rebalancing is performed in the background.
NONE -- Rebalancing is not triggered.
| `ASYNC` |
| `backups` | The number of [backup partitions](/docs/gridgain/gridgain-8/architecture/data-distribution/data-partitioning.md#backup-partitions) for the cache. | `0` |
| `partitionLossPolicy` | [Partition loss policy](/docs/gridgain/gridgain-8/architecture/replication-and-consistency/partition-loss-policy.md). | `IGNORE` |
| `readFromBackup` | Read requested cache entry from the backup partition if it is available on the local node instead of making a request to the primary partition (which can be located on the remote nodes).
Note: This property doesn't work with SQL joins.
| `true` |
| `queryParallelism` | The number of threads in a single node to process a SQL query executed on the cache. Refer to the [Query Parallelism](/docs/gridgain/gridgain-8/tuning-and-troubleshooting/performance-tuning/sql-tuning.md#query-parallelism) section in the Performance guide for more information. | 1 |
| {% endtab %} | | |
{% tab title="Java" %}
```java
CacheConfiguration cacheCfg = new CacheConfiguration("myCache");
cacheCfg.setCacheMode(CacheMode.PARTITIONED);
cacheCfg.setBackups(2);
cacheCfg.setRebalanceMode(CacheRebalanceMode.SYNC);
cacheCfg.setWriteSynchronizationMode(CacheWriteSynchronizationMode.FULL_SYNC);
cacheCfg.setPartitionLossPolicy(PartitionLossPolicy.READ_ONLY_SAFE);
IgniteConfiguration cfg = new IgniteConfiguration();
cfg.setCacheConfiguration(cacheCfg);
// Start a node.
Ignition.start(cfg);
```
For the full list of parameters, refer to the `CacheConfiguration` javadoc.
| Parameter | Description | Default Value |
| -------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- |
| `name` | The cache name. | None. |
| `cacheMode` | The cacheMode parameter defines the way data is distributed in the cluster.
In the PARTITIONED mode (default), the overall data set is divided into partitions and all partitions are split between participating nodes in a balanced manner.
In the REPLICATED mode, all the data is replicated to every node in the cluster.
See the Partitioned/Replicated Mode section for more details.
| `PARTITIONED` |
| `writeSynchronizationMode` | Write synchronization mode. Refer to the [Configuring Partition Backups](/docs/gridgain/gridgain-8/gridgain8-development/caches-and-memory/configuring-caches/configuring-backups.md) section. | `PRIMARY_SYNC` |
| `rebalanceMode` | This parameter controls the way the rebalancing process is performed. Possible values include:
SYNC -- Any requests to the cache's API are blocked until rebalancing is completed.
ASYNC (default) -- Rebalancing is performed in the background.
NONE -- Rebalancing is not triggered.
| `ASYNC` |
| `backups` | The number of [backup partitions](/docs/gridgain/gridgain-8/architecture/data-distribution/data-partitioning.md#backup-partitions) for the cache. | `0` |
| `partitionLossPolicy` | [Partition loss policy](/docs/gridgain/gridgain-8/architecture/replication-and-consistency/partition-loss-policy.md). | `IGNORE` |
| `readFromBackup` | Read requested cache entry from the backup partition if it is available on the local node instead of making a request to the primary partition (which can be located on the remote nodes).
Note: This property doesn't work with SQL joins.
| `true` |
| `queryParallelism` | The number of threads in a single node to process a SQL query executed on the cache. Refer to the [Query Parallelism](/docs/gridgain/gridgain-8/tuning-and-troubleshooting/performance-tuning/sql-tuning.md#query-parallelism) section in the Performance guide for more information. | 1 |
| {% endtab %} | | |
{% tab title="C#/.NET" %}
```csharp
var cfg = new IgniteConfiguration
{
CacheConfiguration = new[]
{
new CacheConfiguration
{
Name = "myCache",
CacheMode = CacheMode.Partitioned,
Backups = 2,
RebalanceMode = CacheRebalanceMode.Sync,
WriteSynchronizationMode = CacheWriteSynchronizationMode.FullSync,
PartitionLossPolicy = PartitionLossPolicy.ReadOnlySafe
}
}
};
Ignition.Start(cfg);
```
{% endtab %}
{% tab title="SQL" %}
```sql
CREATE TABLE IF NOT EXISTS Person (
id int,
city_id int,
name varchar,
age int,
company varchar,
PRIMARY KEY (id, city_id)
) WITH "cache_name=myCache,template=partitioned,backups=2";
```
For the full list of parameters, refer to the [CREATE TABLE](/docs/gridgain/gridgain-8/reference/sql/ddl.md#create-table) section.
{% endtab %}
{% tab title="C++" %}
unsupported
{% endtab %}
{% endtabs %}
## Cache Templates
A cache template is an instance of `CacheConfiguration` that can be registered in the cluster and used later as a basis for creating new caches or SQL tables. A cache or table created from a template inherits all the properties of the template.
Templates can be used in many contexts: on servers, clients (thin and thick), in SQL (e.g., CREATE TABLE), in commands such as `createCache` and `getOrCreateCache`, as well as in the REST API calls. For example, thin clients and SQL do not support some cache configuration properties, and cache templates can be used to work around this limitation.
To create a template, define a cache configuration and add it to the `Ignite` instance, as shown below. If you want do define a cache template in the XML configuration file, you must add an asterisk to the template's name. This is required to indicate that the configuration is a template and not an actual cache.
{% tabs %}
{% tab title="XML" %}
```xml
```
{% endtab %}
{% tab title="Java" %}
```java
IgniteConfiguration igniteCfg = new IgniteConfiguration();
try (Ignite ignite = Ignition.start(igniteCfg)) {
CacheConfiguration cacheCfg = new CacheConfiguration("myCacheTemplate");
cacheCfg.setBackups(2);
cacheCfg.setCacheMode(CacheMode.PARTITIONED);
// Register the cache template
ignite.addCacheConfiguration(cacheCfg);
}
```
{% endtab %}
{% tab title="C#/.NET" %}
```csharp
var ignite = Ignition.Start();
var cfg = new CacheConfiguration
{
Name = "myCacheTemplate*",
CacheMode = CacheMode.Partitioned,
Backups = 2
};
ignite.AddCacheConfiguration(cfg);
```
{% endtab %}
{% tab title="C++" %}
unsupported
{% endtab %}
{% endtabs %}
Once the cache template is registered in the cluster, as shown in the code snippet above, you can use it to create another cache with the same configuration.