Package oracle.kv

Class RequestLimitConfig

java.lang.Object

oracle.kv.RequestLimitConfig

All Implemented Interfaces:

java.io.Serializable

public class RequestLimitConfig
extends java.lang.Object
implements java.io.Serializable

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, Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static int	DEFAULT_MAX_ACTIVE_REQUESTS	The default maximum number of active requests.
static int	DEFAULT_NODE_LIMIT_PERCENT	The default limit on the number of requests, as a percentage of the requested maximum active requests.
static int	DEFAULT_REQUEST_THRESHOLD_PERCENT	The default threshold for activating request limiting, as a percentage of the requested maximum active requests.

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
static RequestLimitConfig	getDefault()	Returns an instance that uses the default values.
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.
java.lang.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 maximum number of active requests.

See Also:

Constant Field Values

DEFAULT_REQUEST_THRESHOLD_PERCENT

public static final int DEFAULT_REQUEST_THRESHOLD_PERCENT

The default threshold for activating request limiting, as a percentage of the requested maximum active requests.

See Also:

Constant Field Values

DEFAULT_NODE_LIMIT_PERCENT

public static final int DEFAULT_NODE_LIMIT_PERCENT

The default limit on the number of requests, as a percentage of the requested maximum active requests.

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.

Throws:

java.lang.IllegalArgumentException - if any argument is 0 or less, if requestThresholdPercent is greater than 100, or if nodeLimitPercent is greater than requestThresholdPercent

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 java.lang.String toString()

Overrides:

toString in class java.lang.Object

getDefault

public static RequestLimitConfig getDefault()

Returns an instance that uses the default values.