public interface ResourceManager
GemFire Cache
.
Re-balancing the GemFire Cache resources can be accomplished using a RebalanceOperation
:
ResourceManager resourceManager = cache.getResourceManager(); RebalanceOperation rebalanceOp = resourceManager.createRebalanceFactory().start();Monitoring of heap utilization is enabled by setting the critical heap percentage using
setCriticalHeapPercentage(float)
.Modifier and Type | Field and Description |
---|---|
static float |
DEFAULT_CRITICAL_HEAP_PERCENTAGE
The default percent of heap memory at which the VM is considered in a
critical state.
|
static float |
DEFAULT_EVICTION_HEAP_PERCENTAGE
The default percent of heap memory at which the VM should begin evicting
data.
|
Modifier and Type | Method and Description |
---|---|
RebalanceFactory |
createRebalanceFactory()
Creates a factory for defining and starting
RebalanceOperations . |
float |
getCriticalHeapPercentage()
Get the percentage of heap at or above which the cache is considered in
danger of becoming inoperable.
|
float |
getEvictionHeapPercentage()
Get the percentage of heap at or above which the eviction should begin on
Regions configured for HeapLRU eviction.
|
Set<RebalanceOperation> |
getRebalanceOperations()
Returns a set of all active
RebalanceOperations that were started locally on this member. |
void |
setCriticalHeapPercentage(float heapPercentage)
Set the percentage of heap at or above which the cache is considered in
danger of becoming inoperable due to garbage collection pauses or out of
memory exceptions.
|
void |
setEvictionHeapPercentage(float heapPercentage)
Set the percentage of heap at or above which the eviction should begin on
Regions configured for HeapLRU eviction.
|
static final float DEFAULT_CRITICAL_HEAP_PERCENTAGE
0.0
.static final float DEFAULT_EVICTION_HEAP_PERCENTAGE
0.0
.
Note that if a HeapLRU is created and the eviction heap percentage has not
been set then it will default 80.0
unless the critical heap percentage
has been set in which case it will default to a value 5.0
less than
the critical heap percentage.RebalanceFactory createRebalanceFactory()
RebalanceOperations
.Set<RebalanceOperation> getRebalanceOperations()
RebalanceOperations
that were started locally on this member.void setCriticalHeapPercentage(float heapPercentage)
Changing this value can cause LowMemoryException
to be thrown from
the following Cache
operations:
Region.put(Object, Object)
Region.put(Object, Object, Object)
Region.create(Object, Object)
Region.create(Object, Object, Object)
Region.putAll(java.util.Map)
Function
s whose Function.optimizeForWrite()
returns true.
Only one change to this attribute or the eviction heap percentage will be
allowed at any given time and its effect will be fully realized before the
next change is allowed.
When using this threshold, the VM must be launched with the -Xmx
and
-Xms
switches set to the same values. Many virtual machine implementations
have additional VM switches to control the behavior of the garbage
collector. We suggest that you investigate tuning the garbage collector
when using this type of eviction controller. A collector that frequently
collects is needed to keep our heap usage up to date.
In particular, on the Sun HotSpot VM, the
-XX:+UseConcMarkSweepGC
flag needs to be set, and
-XX:CMSInitiatingOccupancyFraction=N
should be set with N being a percentage
that is less than the ResourceManager
critical and eviction heap thresholds.
The JRockit VM has similar flags, -Xgc:gencon
and -XXgcTrigger:N
, which are
required if using this feature. Please Note: the JRockit gcTrigger flag is based on heap free, not
heap in use like the GemFire parameter. This means you need to set gcTrigger to 100-N. for example, if your
eviction threshold is 30 percent, you will need to set gcTrigger to 70 percent.
On the IBM VM, the flag to get a similar collector is -Xgcpolicy:gencon
, but there is no
corollary to the gcTrigger/CMSInitiatingOccupancyFraction flags, so when using this feature with an
IBM VM, the heap usage statistics might lag the true memory usage of the VM, and thresholds may need
to be set sufficiently high that the VM will initiate GC before the thresholds are crossed.
heapPercentage
- a percentage of the maximum tenured heap for the VMIllegalStateException
- if the heapPercentage value is not >= 0 or
<= 100 or when less than the current eviction heap percentagegetCriticalHeapPercentage()
,
getEvictionHeapPercentage()
float getCriticalHeapPercentage()
setCriticalHeapPercentage(float)
void setEvictionHeapPercentage(float heapPercentage)
Changing this value may cause eviction to begin immediately.
Only one change to this attribute or critical heap percentage will be allowed at any given time and its effect will be fully realized before the next change is allowed. This feature requires additional VM flags to perform properly. See setCriticalHeapPercentage() for details.
heapPercentage
- a percentage of the maximum tenured heap for the VMIllegalStateException
- if the heapPercentage value is not >= 0 or
<= 100 or when greater than the current critical heap percentage.getEvictionHeapPercentage()
,
getCriticalHeapPercentage()
float getEvictionHeapPercentage()
setEvictionHeapPercentage(float)
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