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Compare Exchange in Cluster-Wide Session
-
Compare-Exchange items can be created and managed on the advanced session (
Session.Advanced)
Other options are listed in this compare-exchange overview. -
When working with compare-exchange items from the session,
the session must be opened as a cluster-wide session. -
In this page:
Create compare-exchange
Example
// The session must be first opened with cluster-wide mode
session.Advanced.ClusterTransaction.CreateCompareExchangeValue(
key: "Best NoSQL Transactional Database",
value: "RavenDB"
);
session.SaveChanges();// The session must be first opened with cluster-wide mode
session.Advanced.ClusterTransaction.CreateCompareExchangeValue(
key: "Best NoSQL Transactional Database",
value: "RavenDB"
);
await session.SaveChangesAsync();SaveChanges()throws aConcurrencyExceptionif the key already exists.- An
InvalidOperationExceptionexception is thrown if the session was Not opened as cluster-wide.
Syntax
session.Advanced.ClusterTransaction.CreateCompareExchangeValue<T>(key, value);session.Advanced.ClusterTransaction.CreateCompareExchangeValue<T>(key, value);| Parameters | Type | Description |
|---|---|---|
| key | string |
The compare-exchange item key. This string can be up to 512 bytes. |
| value | T |
The associated value to store for the key |
| Return Value | Description |
|---|---|
CompareExchangeValue<T> |
The new compare-exchange item is returned |
The CompareExchangeValue
| Parameters | Type | Description |
|---|---|---|
| key | string |
The compare-exchange item key. This string can be up to 512 bytes. |
| value | T |
The value associated with the key |
| index | long |
Index for concurrency control |
Get compare-exchange
Get single value
session.Advanced.ClusterTransaction.GetCompareExchangeValue<T>(key);await session.Advanced.ClusterTransaction.GetCompareExchangeValueAsync<T>(key);| Parameters | Type | Description |
|---|---|---|
| key | string |
The key to retrieve |
| Return Value | Description |
|---|---|
CompareExchangeValue<T> |
If the key doesn't exist it will return null |
Get multiple values
session.Advanced.ClusterTransaction.GetCompareExchangeValues<T>(keys);await session.Advanced.ClusterTransaction.GetCompareExchangeValuesAsync<T>(keys);| Parameters | Type | Description |
|---|---|---|
| keys | string[] |
Array of keys to retrieve |
| Return Value | Description |
|---|---|
Dictionary<string, CompareExchangeValue<T>> |
If a key doesn't exists the associate value will be null |
Get compare-exchange lazily
// Single value
session.Advanced.ClusterTransaction.Lazily.GetCompareExchangeValue<T>(key);
// Multiple values
session.Advanced.ClusterTransaction.Lazily.GetCompareExchangeValues<T>(keys);// Single value
session.Advanced.ClusterTransaction.Lazily.GetCompareExchangeValueAsync<T>(key);
// Multiple values
session.Advanced.ClusterTransaction.Lazily.GetCompareExchangeValuesAsync<T>(keys);| Parameters | Type | Description |
|---|---|---|
| key | string |
The key to retrieve |
| keys | string[] |
Array of keys to retrieve |
| Return Value | Description |
|---|---|
Lazy<CompareExchangeValue<T>> |
If the key doesn't exist it will return null |
Lazy<Dictionary<string, CompareExchangeValue<T>>> |
If a key doesn't exists the associate value will be null |
Delete compare-exchange
// Delete by key & index
session.Advanced.ClusterTransaction.DeleteCompareExchangeValue(key, index);
// Delete by compare-exchange item
session.Advanced.ClusterTransaction.DeleteCompareExchangeValue<T>(item);// Delete by key & index
session.Advanced.ClusterTransaction.DeleteCompareExchangeValue(key, index);
// Delete by compare-exchange item
session.Advanced.ClusterTransaction.DeleteCompareExchangeValue<T>(item);| Parameters | Type | Description |
|---|---|---|
| key | string |
The key of the compare-exchange item to delete |
| index | long |
The index of this compare-exchange item |
| item | CompareExchangeValue<T> |
The compare-exchange item to delete |
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