DDS_DataWriterResourceLimitsQosPolicy Struct Reference
[DATA_WRITER_RESOURCE_LIMITS]

Various settings that configure how a DDS_DataWriter allocates and uses physical memory for internal resources. More...

Data Fields
DDS_Long	initial_concurrent_blocking_threads
	The initial number of threads that are allowed to concurrently block on write call on the same DDS_DataWriter.
DDS_Long	max_concurrent_blocking_threads
	The maximum number of threads that are allowed to concurrently block on write call on the same DDS_DataWriter.
DDS_Long	max_remote_reader_filters
	The maximum number of remote readers for which the writer will perform content-based filtering.
DDS_Long	initial_batches
	Represents the initial number of batches a DDS_DataWriter will manage.
DDS_Long	max_batches
	Represents the maximum number of batches a DDS_DataWriter will manage.
DDS_DataWriterResourceLimitsInstanceReplacementKind	instance_replacement
	Sets the kinds of instances allowed to be replaced when instance resource limits are reached.
DDS_Boolean	replace_empty_instances
	Whether or not to replace empty instances during instance replacement.
DDS_Boolean	autoregister_instances
	Whether or not to automatically register new instances.

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Detailed Description

Various settings that configure how a DDS_DataWriter allocates and uses physical memory for internal resources.

DataWriters must allocate internal structures to handle the simultaneously blocking of threads trying to call FooDataWriter_write on the same DDS_DataWriter, for the storage used to batch small samples, and for content-based filters specified by DataReaders.

Most of these internal structures start at an initial size and, by default, will be grown as needed by dynamically allocating additional memory. You may set fixed, maximum sizes for these internal structures if you want to bound the amount of memory that can be used by a DDS_DataWriter. By setting the initial size to the maximum size, you will prevent RTI Data Distribution Service from dynamically allocating any memory after the creation of the DDS_DataWriter.

This QoS policy is an extension to the DDS standard.

Entity:

DDS_DataWriter

Properties:

RxO = N/A
Changeable = NO

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Field Documentation

DDS_Long DDS_DataWriterResourceLimitsQosPolicy::initial_concurrent_blocking_threads

The initial number of threads that are allowed to concurrently block on write call on the same DDS_DataWriter.

This value only applies if DDS_HistoryQosPolicy has its kind set to DDS_KEEP_ALL_HISTORY_QOS and DDS_ReliabilityQosPolicy::max_blocking_time is > 0.

[default] 1

[range] [1, 10000], <= max_concurrent_blocking_threads

DDS_Long DDS_DataWriterResourceLimitsQosPolicy::max_concurrent_blocking_threads

The maximum number of threads that are allowed to concurrently block on write call on the same DDS_DataWriter.

This value only applies if DDS_HistoryQosPolicy has its kind set to DDS_KEEP_ALL_HISTORY_QOS and DDS_ReliabilityQosPolicy::max_blocking_time is > 0.

[default] DDS_LENGTH_UNLIMITED

[range] [1, 10000] or DDS_LENGTH_UNLIMITED, >= initial_concurrent_blocking_threads

DDS_Long DDS_DataWriterResourceLimitsQosPolicy::max_remote_reader_filters

The maximum number of remote readers for which the writer will perform content-based filtering.

[default] 32

[range] [0, 32]

DDS_Long DDS_DataWriterResourceLimitsQosPolicy::initial_batches

Represents the initial number of batches a DDS_DataWriter will manage.

[default] 8

[range] [1,100 million]

See also:

DDS_BatchQosPolicy

DDS_Long DDS_DataWriterResourceLimitsQosPolicy::max_batches

Represents the maximum number of batches a DDS_DataWriter will manage.

[default] DDS_LENGTH_UNLIMITED

When batching is enabled, the maximum number of samples that a DDS_DataWriter can store is limited by this value and DDS_ResourceLimitsQosPolicy::max_samples.

[range] [1,100 million] or DDS_LENGTH_UNLIMITED >= DDS_RtpsReliableWriterProtocol_t::heartbeats_per_max_samples if batching is enabled

See also:

DDS_BatchQosPolicy

DDS_DataWriterResourceLimitsInstanceReplacementKind DDS_DataWriterResourceLimitsQosPolicy::instance_replacement

Sets the kinds of instances allowed to be replaced when instance resource limits are reached.

When a DDS_DataWriter's number of active instances is greater than DDS_ResourceLimitsQosPolicy::max_instances, it will try to make room by replacing an existing instance. This field specifies the kinds of instances allowed to be replaced.

If a replaceable instance is not available, either an out-of-resources exception will be returned, or the writer may block if the instance reclamation was done when writing.

[default] DDS_UNREGISTERED_INSTANCE_REPLACEMENT

See also:

DDS_DataWriterResourceLimitsInstanceReplacementKind

DDS_Boolean DDS_DataWriterResourceLimitsQosPolicy::replace_empty_instances

Whether or not to replace empty instances during instance replacement.

When a DDS_DataWriter has more active instances than allowed by DDS_ResourceLimitsQosPolicy::max_instances, it tries to make room by replacing an existing instance. This field configures whether empty instances (i.e. instances with no samples) may be replaced. If set DDS_BOOLEAN_TRUE, then a DDS_DataWriter will first try reclaiming empty instances, before trying to replace whatever is specified by DDS_DataWriterResourceLimitsQosPolicy::instance_replacement.

[default] DDS_BOOLEAN_FALSE

See also:

DDS_DataWriterResourceLimitsInstanceReplacementKind

DDS_Boolean DDS_DataWriterResourceLimitsQosPolicy::autoregister_instances

Whether or not to automatically register new instances.

[default] DDS_BOOLEAN_TRUE

When set to true, it is possible to write with a non-NIL handle of an instance that is not registered: the write operation will succeed and the instance will be registered. Otherwise, that write operation would fail.

See also:

FooDataWriter_write