PoolingOptions (DataStax Java Driver for Apache Cassandra

java.lang.Object
- com.datastax.driver.core.PoolingOptions

```
public class PoolingOptions
extends Object
```
Options related to connection pooling.
The driver uses connections in an asynchronous manner, meaning that multiple requests can be submitted on the same connection at the same time. Therefore only a relatively small number of connections is needed. For each host, the driver uses a connection pool that may have a variable size (it will automatically adjust to the current load).
With ProtocolVersion#V2 or below, there are at most 128 simultaneous requests per connection, so the pool defaults to a variable size. You will typically raise the maximum capacity by adding more connections with setMaxRequestsPerConnection(HostDistance, int).
With ProtocolVersion#V3 or above, there are up to 32768 requests per connection, and the pool defaults to a fixed size of 1. You will typically raise the maximum capacity by allowing more simultaneous requests per connection (setMaxRequestsPerConnection(HostDistance, int)).
All parameters can be separately set for LOCAL and REMOTE hosts (HostDistance). For IGNORED hosts, no connections are created so these settings cannot be changed.

Constructor Summary

Constructors
Constructor and Description

PoolingOptions()

Constructors
Constructor and Description
`PoolingOptions()`

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`int`	`getCoreConnectionsPerHost(HostDistance distance)` Returns the core number of connections per host.
`int`	`getHeartbeatIntervalSeconds()` Returns the heart beat interval, after which a message is sent on an idle connection to make sure it's still alive.
`int`	`getIdleTimeoutSeconds()` Returns the timeout before an idle connection is removed.
`Executor`	`getInitializationExecutor()` Returns the executor to use for connection initialization.
`int`	`getMaxConnectionsPerHost(HostDistance distance)` Returns the maximum number of connections per host.
`int`	`getMaxRequestsPerConnection(HostDistance distance)` Returns the maximum number of requests per connection.
`int`	`getMaxSimultaneousRequestsPerConnectionThreshold(HostDistance distance)` Deprecated. this method has been renamed to `getNewConnectionThreshold(HostDistance)`. This method calls the new one internally, but you should use the new one in your code.
`int`	`getMaxSimultaneousRequestsPerHostThreshold(HostDistance distance)` Deprecated. this method has been renamed to `getMaxRequestsPerConnection(HostDistance)`. This method calls the new one internally, but you should use the new one in your code.
`int`	`getMinSimultaneousRequestsPerConnectionThreshold(HostDistance distance)` Deprecated. this option isn't used anymore with the current pool resizing algorithm.
`int`	`getNewConnectionThreshold(HostDistance distance)` Returns the threshold that triggers the creation of a new connection to a host.
`int`	`getPoolTimeoutMillis()` Returns the timeout when trying to acquire a connection from a host's pool.
`void`	`refreshConnectedHost(Host host)` Requests the driver to re-evaluate the `HostDistance` for a given node.
`void`	`refreshConnectedHosts()` Requests the driver to re-evaluate the `HostDistance` (through the configured `LoadBalancingPolicy.distance(com.datastax.driver.core.Host)`) for every known hosts and to drop/add connections to each hosts according to the computed distance.
`PoolingOptions`	`setConnectionsPerHost(HostDistance distance, int core, int max)` Sets the core and maximum number of connections per host in one call.
`PoolingOptions`	`setCoreConnectionsPerHost(HostDistance distance, int newCoreConnections)` Sets the core number of connections per host.
`PoolingOptions`	`setHeartbeatIntervalSeconds(int heartbeatIntervalSeconds)` Sets the heart beat interval, after which a message is sent on an idle connection to make sure it's still alive.
`PoolingOptions`	`setIdleTimeoutSeconds(int idleTimeoutSeconds)` Sets the timeout before an idle connection is removed.
`PoolingOptions`	`setInitializationExecutor(Executor initializationExecutor)` Sets the executor to use for connection initialization.
`PoolingOptions`	`setMaxConnectionsPerHost(HostDistance distance, int newMaxConnections)` Sets the maximum number of connections per host.
`PoolingOptions`	`setMaxRequestsPerConnection(HostDistance distance, int newMaxRequests)` Sets the maximum number of requests per connection.
`PoolingOptions`	`setMaxSimultaneousRequestsPerConnectionThreshold(HostDistance distance, int newMaxSimultaneousRequests)` Deprecated. this method has been renamed to `setNewConnectionThreshold(HostDistance, int)`. This method calls the new one internally, but you should use the new one in your code.
`PoolingOptions`	`setMaxSimultaneousRequestsPerHostThreshold(HostDistance distance, int newMaxRequests)` Deprecated. this method has been renamed to `setMaxRequestsPerConnection(HostDistance, int)`. This method calls the new one internally, but you should use the new one in your code.
`PoolingOptions`	`setMinSimultaneousRequestsPerConnectionThreshold(HostDistance distance, int newMinSimultaneousRequests)` Deprecated. this option isn't used anymore with the current pool resizing algorithm.
`PoolingOptions`	`setNewConnectionThreshold(HostDistance distance, int newValue)` Sets the threshold that triggers the creation of a new connection to a host.
`PoolingOptions`	`setPoolTimeoutMillis(int poolTimeoutMillis)` Sets the timeout when trying to acquire a connection from a host's pool.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - PoolingOptions
```
public PoolingOptions()
```
- Method Detail
  - getCoreConnectionsPerHost
```
public int getCoreConnectionsPerHost(HostDistance distance)
```
    Returns the core number of connections per host.
    
    Parameters:
    
    distance - the HostDistance for which to return this threshold.
    
    Returns:
    
    the core number of connections per host at distance distance.
  - setCoreConnectionsPerHost
```
public PoolingOptions setCoreConnectionsPerHost(HostDistance distance,
                                                int newCoreConnections)
```
    Sets the core number of connections per host.
    For the provided distance, this corresponds to the number of connections initially created and kept open to each host of that distance.
    The default value is:
    - with ProtocolVersion#V2 or below: 2 for LOCAL hosts and 1 for REMOTE hosts.
    - with ProtocolVersion#V3 or above: 1 for all hosts.
    Parameters:
    
    distance - the HostDistance for which to set this threshold.
    
    newCoreConnections - the value to set
    
    Returns:
    
    this PoolingOptions.
    
    Throws:
    
    IllegalArgumentException - if distance == HostDistance.IGNORED, or if newCoreConnections is greater than the maximum value for this distance.
    
    See Also:
    
    setConnectionsPerHost(HostDistance, int, int)
  - getMaxConnectionsPerHost
```
public int getMaxConnectionsPerHost(HostDistance distance)
```
    Returns the maximum number of connections per host.
    
    Parameters:
    
    distance - the HostDistance for which to return this threshold.
    
    Returns:
    
    the maximum number of connections per host at distance distance.
  - setMaxConnectionsPerHost
```
public PoolingOptions setMaxConnectionsPerHost(HostDistance distance,
                                               int newMaxConnections)
```
    Sets the maximum number of connections per host.
    For the provided distance, this corresponds to the maximum number of connections that can be created per host at that distance.
    The default value is:
    - with ProtocolVersion#V2 or below: 8 for LOCAL hosts and 2 for REMOTE hosts.
    - with ProtocolVersion#V3 or above: 1 for all hosts.
    Parameters:
    
    distance - the HostDistance for which to set this threshold.
    
    newMaxConnections - the value to set
    
    Returns:
    
    this PoolingOptions.
    
    Throws:
    
    IllegalArgumentException - if distance == HostDistance.IGNORED, or if newMaxConnections is less than the core value for this distance.
    
    See Also:
    
    setConnectionsPerHost(HostDistance, int, int)
  - setConnectionsPerHost
```
public PoolingOptions setConnectionsPerHost(HostDistance distance,
                                            int core,
                                            int max)
```
    Sets the core and maximum number of connections per host in one call.
    This is a convenience method that is equivalent to calling setCoreConnectionsPerHost(HostDistance, int) and setMaxConnectionsPerHost(HostDistance, int).
    
    Parameters:
    
    distance - the HostDistance for which to set these threshold.
    
    core - the core number of connections.
    
    max - the max number of connections.
    
    Returns:
    
    this PoolingOptions.
    
    Throws:
    
    IllegalArgumentException - if distance == HostDistance.IGNORED, or if core > max.
  - getNewConnectionThreshold
```
public int getNewConnectionThreshold(HostDistance distance)
```
    Returns the threshold that triggers the creation of a new connection to a host.
    
    Parameters:
    
    distance - the HostDistance for which to return this threshold.
    
    Returns:
    
    the configured threshold, or the default one if none have been set.
    
    See Also:
    
    setNewConnectionThreshold(HostDistance, int)
  - setNewConnectionThreshold
```
public PoolingOptions setNewConnectionThreshold(HostDistance distance,
                                                int newValue)
```
    Sets the threshold that triggers the creation of a new connection to a host.
    A new connection gets created if:
    - N connections are open
    - N < getMaxConnectionsPerHost(HostDistance)
    - the number of active requests is more than (N - 1) * getMaxRequestsPerConnection(HostDistance) + getNewConnectionThreshold(HostDistance)
    In other words, if all but the last connection are full, and the last connection is above this threshold.
    The default value is:
    - with ProtocolVersion#V2 or below: 100 for all hosts.
    - with ProtocolVersion#V3 or above: 800 for LOCAL hosts and 200 for REMOTE hosts.
    Parameters:
    
    distance - the HostDistance for which to configure this threshold.
    
    newValue - the value to set (between 0 and 128).
    
    Returns:
    
    this PoolingOptions.
    
    Throws:
    
    IllegalArgumentException - if distance == HostDistance.IGNORED, or if maxSimultaneousRequests is not in range, or if newValue is less than the minimum value for this distance.
  - getMaxRequestsPerConnection
```
public int getMaxRequestsPerConnection(HostDistance distance)
```
    Returns the maximum number of requests per connection.
    
    Parameters:
    
    distance - the HostDistance for which to return this threshold.
    
    Returns:
    
    the maximum number of requests per connection at distance distance.
    
    See Also:
    
    setMaxRequestsPerConnection(HostDistance, int)
  - setMaxRequestsPerConnection
```
public PoolingOptions setMaxRequestsPerConnection(HostDistance distance,
                                                  int newMaxRequests)
```
    Sets the maximum number of requests per connection.
    The default value is:
    - with ProtocolVersion#V2 or below: 128 for all hosts (there should not be any reason to change this).
    - with ProtocolVersion#V3 or above: 1024 for LOCAL hosts and 256 for REMOTE hosts. These values were chosen so that the default V2 and V3 configuration generate the same load on a Cassandra cluster. Protocol V3 can go much higher (up to 32768), so if your number of clients is low, don't hesitate to experiment with higher values. If you have more than one connection per host, consider also adjusting setNewConnectionThreshold(HostDistance, int).
    Parameters:
    
    distance - the HostDistance for which to set this threshold.
    
    newMaxRequests - the value to set.
    
    Returns:
    
    this PoolingOptions.
    
    Throws:
    
    IllegalArgumentException - if distance == HostDistance.IGNORED, or if newMaxConnections is not within the allowed range.
  - getIdleTimeoutSeconds
```
public int getIdleTimeoutSeconds()
```
    Returns the timeout before an idle connection is removed.
    
    Returns:
    
    the timeout.
  - setIdleTimeoutSeconds
```
public PoolingOptions setIdleTimeoutSeconds(int idleTimeoutSeconds)
```
    Sets the timeout before an idle connection is removed.
    The order of magnitude should be a few minutes (the default is 120 seconds). The timeout that triggers the removal has a granularity of 10 seconds.
    
    Parameters:
    
    idleTimeoutSeconds - the new timeout in seconds.
    
    Returns:
    
    this PoolingOptions.
    
    Throws:
    
    IllegalArgumentException - if the timeout is negative.
  - getPoolTimeoutMillis
```
public int getPoolTimeoutMillis()
```
    Returns the timeout when trying to acquire a connection from a host's pool.
    
    Returns:
    
    the timeout.
  - setPoolTimeoutMillis
```
public PoolingOptions setPoolTimeoutMillis(int poolTimeoutMillis)
```
    Sets the timeout when trying to acquire a connection from a host's pool.
    If no connection is available within that time, the driver will try the next host from the query plan.
    The default is 5 seconds. If this option is set to zero, the driver won't wait at all.
    
    Parameters:
    
    poolTimeoutMillis - the new value in milliseconds.
    
    Returns:
    
    this PoolingOptions
    
    Throws:
    
    IllegalArgumentException - if the timeout is negative.
  - getHeartbeatIntervalSeconds
```
public int getHeartbeatIntervalSeconds()
```
    Returns the heart beat interval, after which a message is sent on an idle connection to make sure it's still alive.
    
    Returns:
    
    the interval.
  - setHeartbeatIntervalSeconds
```
public PoolingOptions setHeartbeatIntervalSeconds(int heartbeatIntervalSeconds)
```
    Sets the heart beat interval, after which a message is sent on an idle connection to make sure it's still alive.
    This is an application-level keep-alive, provided for convenience since adjusting the TCP keep-alive might not be practical in all environments.
    This option should be set higher than SocketOptions.getReadTimeoutMillis().
    The default value for this option is 30 seconds.
    
    Parameters:
    
    heartbeatIntervalSeconds - the new value in seconds. If set to 0, it will disable the feature.
    
    Returns:
    
    this PoolingOptions
    
    Throws:
    
    IllegalArgumentException - if the interval is negative.
  - getInitializationExecutor
```
public Executor getInitializationExecutor()
```
    Returns the executor to use for connection initialization.
    
    Returns:
    
    the executor.
    
    See Also:
    
    setInitializationExecutor(java.util.concurrent.Executor)
  - setInitializationExecutor
```
public PoolingOptions setInitializationExecutor(Executor initializationExecutor)
```
    Sets the executor to use for connection initialization.
    Connections are open in a completely asynchronous manner. Since initializing the transport requires separate CQL queries, the futures representing the completion of these queries are transformed and chained. This executor is where these transformations happen.
    This is an advanced option, which should be rarely needed in practice. It defaults to Guava's MoreExecutors.sameThreadExecutor(), which results in running the transformations on the network I/O threads; this is fine if the transformations are fast and not I/O bound (which is the case by default). One reason why you might want to provide a custom executor is if you use authentication with a custom Authenticator implementation that performs blocking calls.
    
    Parameters:
    
    initializationExecutor - the executor to use
    
    Returns:
    
    this PoolingOptions
    
    Throws:
    
    NullPointerException - if the executor is null
  - refreshConnectedHosts
```
public void refreshConnectedHosts()
```
    Requests the driver to re-evaluate the HostDistance (through the configured LoadBalancingPolicy.distance(com.datastax.driver.core.Host)) for every known hosts and to drop/add connections to each hosts according to the computed distance.
  - refreshConnectedHost
```
public void refreshConnectedHost(Host host)
```
    Requests the driver to re-evaluate the HostDistance for a given node.
    
    Parameters:
    
    host - the host to refresh.
    
    See Also:
    
    refreshConnectedHosts()
  - getMinSimultaneousRequestsPerConnectionThreshold
```
@Deprecated
public int getMinSimultaneousRequestsPerConnectionThreshold(HostDistance distance)
```
    Deprecated. this option isn't used anymore with the current pool resizing algorithm.
  - setMinSimultaneousRequestsPerConnectionThreshold
```
@Deprecated
public PoolingOptions setMinSimultaneousRequestsPerConnectionThreshold(HostDistance distance,
                                                                                   int newMinSimultaneousRequests)
```
    Deprecated. this option isn't used anymore with the current pool resizing algorithm.
  - getMaxSimultaneousRequestsPerConnectionThreshold
```
@Deprecated
public int getMaxSimultaneousRequestsPerConnectionThreshold(HostDistance distance)
```
    Deprecated. this method has been renamed to getNewConnectionThreshold(HostDistance). This method calls the new one internally, but you should use the new one in your code.
  - setMaxSimultaneousRequestsPerConnectionThreshold
```
@Deprecated
public PoolingOptions setMaxSimultaneousRequestsPerConnectionThreshold(HostDistance distance,
                                                                                   int newMaxSimultaneousRequests)
```
    Deprecated. this method has been renamed to setNewConnectionThreshold(HostDistance, int). This method calls the new one internally, but you should use the new one in your code.
  - getMaxSimultaneousRequestsPerHostThreshold
```
@Deprecated
public int getMaxSimultaneousRequestsPerHostThreshold(HostDistance distance)
```
    Deprecated. this method has been renamed to getMaxRequestsPerConnection(HostDistance). This method calls the new one internally, but you should use the new one in your code.
  - setMaxSimultaneousRequestsPerHostThreshold
```
@Deprecated
public PoolingOptions setMaxSimultaneousRequestsPerHostThreshold(HostDistance distance,
                                                                             int newMaxRequests)
```
    Deprecated. this method has been renamed to setMaxRequestsPerConnection(HostDistance, int). This method calls the new one internally, but you should use the new one in your code.

Class PoolingOptions

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

PoolingOptions

Method Detail

getCoreConnectionsPerHost

setCoreConnectionsPerHost

getMaxConnectionsPerHost

setMaxConnectionsPerHost

setConnectionsPerHost

getNewConnectionThreshold

setNewConnectionThreshold

getMaxRequestsPerConnection

setMaxRequestsPerConnection

getIdleTimeoutSeconds

setIdleTimeoutSeconds

getPoolTimeoutMillis

setPoolTimeoutMillis

getHeartbeatIntervalSeconds

setHeartbeatIntervalSeconds

getInitializationExecutor

setInitializationExecutor

refreshConnectedHosts

refreshConnectedHost

getMinSimultaneousRequestsPerConnectionThreshold

setMinSimultaneousRequestsPerConnectionThreshold

getMaxSimultaneousRequestsPerConnectionThreshold

setMaxSimultaneousRequestsPerConnectionThreshold

getMaxSimultaneousRequestsPerHostThreshold

setMaxSimultaneousRequestsPerHostThreshold