oracle.kv
Class RequestLimitConfig

java.lang.Object
  oracle.kv.RequestLimitConfig

public class RequestLimitConfig
extends Object

Describes how requests may be limited so that one or more nodes with long service times don't end up consuming all available threads in the KVS client.

See Also:

KVStoreConfig.setRequestLimit(oracle.kv.RequestLimitConfig), RequestLimitException

Field Summary

static int	DEFAULT_MAX_ACTIVE_REQUESTS The default values for limiting requests to a particular node.
static int	DEFAULT_NODE_LIMIT_PERCENT
static int	DEFAULT_REQUEST_THRESHOLD_PERCENT

Constructor Summary

RequestLimitConfig(int maxActiveRequests, int requestThresholdPercent, int nodeLimitPercent)
Creates a request limiting configuration.

Method Summary

static RequestLimitConfig	getDefault()
int	getMaxActiveRequests() Returns the maximum number of active requests permitted by the KVS client.
int	getNodeLimit() Returns the maximum number of requests that may be active at a node.
int	getNodeLimitPercent() Returns the percentage used to compute the maximum number of requests that may be active at a node.
int	getRequestThreshold() Returns the threshold number of requests above which the request limiting mechanism is activated.
int	getRequestThresholdPercent() Returns the percentage used to compute the active request threshold above which the request limiting mechanism is activated.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

DEFAULT_MAX_ACTIVE_REQUESTS

public static final int DEFAULT_MAX_ACTIVE_REQUESTS

The default values for limiting requests to a particular node.

See Also:

Constant Field Values

DEFAULT_REQUEST_THRESHOLD_PERCENT

public static final int DEFAULT_REQUEST_THRESHOLD_PERCENT

See Also:

Constant Field Values

DEFAULT_NODE_LIMIT_PERCENT

public static final int DEFAULT_NODE_LIMIT_PERCENT

See Also:

Constant Field Values

Constructor Detail

RequestLimitConfig

public RequestLimitConfig(int maxActiveRequests,
                          int requestThresholdPercent,
                          int nodeLimitPercent)

Creates a request limiting configuration. The request limiting mechanism is only activated when the number of active requests exceeds the threshold specified by the parameter requestThresholdPercent. Both the threshold and limit parameters below are expressed as a percentage of maxActiveRequests.

When the mechanism is active the number of active requests to a node is not allowed to exceed nodeRequestLimitPercent. Any new requests that would exceed this limit are rejected and a RequestLimitException is thrown.

For example, consider a configuration with maxActiveRequests=10, requestThresholdPercent=80 and nodeLimitPercent=50. If 8 requests are already active at the client, and a 9th request is received that would be directed at a node which already has 5 active requests, it would result in a RequestLimitException being thrown. If only 7 requests were active at the client, the 8th request would be directed at the node with 5 active requests and the request would be processed normally.

Parameters:

maxActiveRequests - the maximum number of active requests permitted by the KV client. This number is typically derived from the maximum number of threads that the client has set aside for processing requests. The default is 100. Note that the KVStore does not actually enforce this maximum directly. It only uses this parameter as the basis for calculating the requests limits to be enforced at a node.

requestThresholdPercent - the threshold computed as a percentage of maxActiveRequests at which requests are limited. The default is 90.

nodeLimitPercent - determines the maximum number of active requests that can be associated with a node when the request limiting mechanism is active. The default is 80.

Method Detail

getMaxActiveRequests

public int getMaxActiveRequests()

Returns the maximum number of active requests permitted by the KVS client.

The default value is 100.

getRequestThresholdPercent

public int getRequestThresholdPercent()

Returns the percentage used to compute the active request threshold above which the request limiting mechanism is activated.

The default value is 90.

getRequestThreshold

public int getRequestThreshold()

Returns the threshold number of requests above which the request limiting mechanism is activated.

getNodeLimitPercent

public int getNodeLimitPercent()

Returns the percentage used to compute the maximum number of requests that may be active at a node.

The default value is 80.

getNodeLimit

public int getNodeLimit()

Returns the maximum number of requests that may be active at a node.

toString

public String toString()

Overrides:

toString in class Object

getDefault

public static RequestLimitConfig getDefault()