Node::getObjectCaches Method

getObjectCaches(dynObj:    JadeDynamicObject input;
                cacheType: Integer);

The Node class getObjectCaches method retrieves information about cache activity for the node specified as the method receiver. You can call this method using any node as the receiver.

The values are returned as properties of a JadeDynamicObject object, relating to the specified node.

The calling process is responsible for creating and deleting the JadeDynamicObject instance.

An example that shows the use of a method to handle the wrapping of negative values when calculating differences is provided later in this subsection. See also the Node class getObjectCaches method, in Volume 2 of the JADE Encyclopaedia of Classes.

The cacheType parameter specifies whether information is retrieved from the persistent, transient, or remote transient cache. The retrieved values are listed in the following table.

Value	Description
1	Persistent cache
2	Transient cache
3	Remote transient cache (applicable only on server nodes)

You should use a blank dynamic object the first time you call this method, which adds properties to the object. You can then use this object in subsequent calls.

If the dynamic object passed to the method already contains properties but they do not match the properties to be returned, the existing dynamic object properties are removed and then replaced with the appropriate properties.

The getObjectCaches method is most efficient when the properties match those to be returned.

The properties that are returned to the dynamic object specified in the dynObj parameter are listed in the following table.

All Cache Types	Persistent Cache Only	Primitive Type	Value
clockTicks		Integer64
nodeCPUTime		Integer64
nodeTicks		Integer64
cacheType		Integer64
hits		Integer64
misses		Integer64
topOfLRUHits (no longer maintained)		Integer64	0
createdBuffers		Integer64
cleanSwappedBuffers		Integer64
dirtySwappedBuffers		Integer64
resizedBuffers		Integer64
maximumBufferSize		Integer64
totalNumberOfBuffers		Integer64
availableBufferSize		Integer64
maximumOverdraftBufferSize		Integer64
overdraftBufferSize		Integer64
deadBuffers		Integer64
	totalOperations	Integer64
	currentOperations	Integer64
	currentBuffers	Integer64
	deletedBuffers	Integer64
	copiedBuffers	Integer64
	newBuffers	Integer64
	fetches	Integer64
	duplicateFetches	Integer64
	totalSwaps	Integer64
	totalOpsWhenSwapped	Integer64
	minOpsWhenSwapped	Integer64
	maxOpsWhenSwapped	Integer64
	totalAgeWhenSwapped	Integer64
	minAgeWhenSwapped	Integer64
	maxAgeWhenSwapped	Integer64
	lruTraversals	Integer64
	totalLruTraversalTicks	Integer64
	latestLruTraversalTicks	Integer64
	totalCacheCoherencyNotifications	Integer64
	cacheCoherencyNotificationHits	Integer64
	cacheCoherencyUpdatedObjects	Integer64
	cacheCoherencyObjectHits	Integer64
	cacheCoherencyObjectMisses	Integer64
	cacheCoherencyRangeRequests	Integer64
	nodeLockRemoveRequestsSent	Integer64
	nodeLockRemoveRequestsRcvd	Integer64
	nodeLockSwapOutRequestsSent	Integer64

For explanations about these direct node statistics, see "Cache Statistics" under "Statistics File Format", later in this chapter.

The following example that shows the use of the getObjectCaches method to return the number of node ticks over a specified period.

getNodeTicks(seconds: Integer): Integer64;
vars
    sample              : JadeDynamicObject;
    cumulativeNodeTicks : Integer64;
    nodeTicks           : Integer64;
begin
    create sample transient;
    node.getObjectCaches(sample, 1);    // persistent cache
    cumulativeNodeTicks := sample.getPropertyValue("nodeTicks").Integer64;
    process.sleep(seconds*1000);
    node.getObjectCaches(sample, 1);
    nodeTicks := sample.getPropertyValue("nodeTicks");
    if nodeTicks >= cumulativeNodeTicks then
        nodeTicks := nodeTicks – cumulativeNodeTicks;
    else // wrapped to a negative value
        nodeTicks := (Max_Integer64 – cumulativeNodeTicks) + 1 +
                 (nodeTicks – Min_Integer64);
    endif;
    delete sample;
    return nodeTicks;
end;