public interface CPSession
For CP data structures that are doing ownership management of the resources,
such as lock or semaphore, a session is required to keep track of the
liveliness of the caller. In this context, caller means an entity that
uses the CPI subsystem APIs. It can be either a Hazelcast server or client.
A caller initially creates a session before sending its very first
session-based request to the CP group, such as a lock / semaphore acquire.
After creating a session on the CP group, the caller stores its session id
locally and sends it alongside its session-based operations. A single
session is used for all lock and semaphore proxies of the caller. When a CP
group receives a session-based operation, it checks the validity of the
session using the session id information available in the operation.
A session is valid if it is still open in the CP group. An operation with
a valid session id is accepted as a new session heartbeat. While a caller is
idle, in other words, it does not send any session-based operation to the CP
group for a while, it commits periodic heartbeats to the CP group
in the background in order to keep its session alive. This interval is
specified in CPSubsystemConfig.getSessionHeartbeatIntervalSeconds()
.
A session is closed when the caller does not touch the session during
a predefined duration. In this case, the caller is assumed to be crashed and
all its resources are released automatically. This duration is specified in
CPSubsystemConfig.getSessionTimeToLiveSeconds()
. Please check
CPSubsystemConfig
to learn the recommendations for choosing
a reasonable session time-to-live duration.
Sessions offer a trade-off between liveliness and safety. If a very small
value is set to CPSubsystemConfig.setSessionTimeToLiveSeconds(int)
,
then a session owner could be considered crashed very quickly and its
resources can be released prematurely. On the other hand, if a large value
is set, a session could be kept alive for an unnecessarily long duration
even if its owner actually crashes.
CPSubsystemConfig
Modifier and Type | Interface and Description |
---|---|
static class |
CPSession.CPSessionOwnerType
Represents type of endpoints that create CP sessions
|
Modifier and Type | Method and Description |
---|---|
long |
creationTime()
Returns the timestamp of when the session was created
|
Address |
endpoint()
Returns the endpoint that has created this session
|
String |
endpointName()
Returns name of the endpoint that has created this session
|
CPSession.CPSessionOwnerType |
endpointType()
Returns type of the endpoint that has created this session
|
long |
expirationTime()
Returns the timestamp of when the session will expire
|
long |
id()
Returns id of the session
|
boolean |
isExpired(long timestamp)
Returns true if the session expires before the given timestamp.
|
long |
version()
Returns version of the session.
|
long id()
long creationTime()
long expirationTime()
long version()
boolean isExpired(long timestamp)
Address endpoint()
CPSession.CPSessionOwnerType endpointType()
String endpointName()
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