DDS Sample-Data Memory Management for DataWriters

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22.1 DDS Sample-Data Memory Management for DataWriters

To configure DDS sample-data memory management on the writer side, use the 7.5.19 PROPERTY QosPolicy (DDS Extension) . Table 22.1 DDS Sample-Data Memory Management Properties for DataWriters lists the supported memory-management properties for DataWriters.

Table 22.1 DDS Sample-Data Memory Management Properties for DataWriters
Property	Description
dds.data_writer. history.memory_manager. fast_pool.pool_buffer_max_size	If the serialized size of the DDS sample is <= pool_buffer_max_size: The buffer is obtained from a pre-allocated pool and released when the DataWriter is deleted. If the serialized size of the DDS sample is > pool_buffer_max_size: The buffer is dynamically allocated from the heap and returned to the heap when the DDS sample is removed from the DataWriter’s queue. The size of the buffer allocated from the heap is the sample serialized size. Default: -1 (UNLIMITED). All DDS sample buffers are obtained from the pre-allocated pool; the buffer size is the maximum serialized size of the DDS samples, as returned by the type plugin get_serialized_sample_max_size() operation. See 22.1.1 Memory Management without Batching. Note: This property also controls the memory allocation for the serialized key buffer that is stored with every instance. See 22.3 Instance-Data Memory Management for DataWriters.
dds.data_writer. history.memory_manager. java_stream.min_size	Only supported when using the Java API. Defines the minimum size of the buffer that will be used to serialize DDS samples. When a DataWriter is created, the Java layer will allocate a buffer of this size and associate it with the DataWriter. Default: -1 (UNLIMITED). This is a sentinel that refers to the maximum serialized size of a DDS sample, as returned by the type plugin get_serialized_sample_max_size() operation See 22.1.3 Writer-Side Memory Management when Using Java.
dds.data_writer. history.memory_manager. java_stream.trim_to_size	Only supported when using the Java API. A boolean value that controls the growth of the serialization buffer. If set to 0 (default): The buffer will not be reallocated unless the serialized size of a new DDS sample is greater than the current buffer size. If set to 1: The buffer will be reallocated with each new DDS sample to a smaller size in order to just fit the DDS sample serialized size. The new size cannot be smaller than min_size. See 22.1.3 Writer-Side Memory Management when Using Java.