Use Dynamic Memory Management Policy with FastDDS-SH

[marcus89]

Hi everyone,

I want to use change the History Memory Policy to DYNAMIC in the Integration Service.

1 - Below, my working configuration: ROS2 publisher on domain 0 --> Integration Service --> ROS2 subscriber on domain 1

The topic published by the ROS2 node is :

• topicType: sensor_msgs/msg/Image
• topicName: image The quality of service is correctly set (BEST_EFFORT and VOLATILE). This previous configuration works perfectly.

2 - Now, I want to use FastDDS as system in Integration service. Below, my configuration : ROS2 publisher on domain 0 --> Integration Service --> FastDDS subscriber on domain 1

When using this configuration, I get the following error : [DYN_TYPES Error] Error inserting data. The container is full. -> Function insert_sequence_data

This error makes me think that the DYNAMIC Memory Policy is not applied by Integration Service when creating publisher/subscriber.

Can someone confirm this limitation?

Best Regards, Marius

[xixioba]

Is there a solution please? I also had a similar problem

[liufang-robot]

I had a similar problem. I tried to understand what happend.

I think Integration Service uses the DynamicType to handle all the data bridge. For sequene data. here it is:

Firstly, It creates the builder. In Integration Service FASHDDS-SH source code Conversion.cpp here

DynamicTypeBuilder_ptr result = factory->create_sequence_builder(builder, c_type.bounds());

For sequence data in image msg, the c_type.bounds() is 0.

Then in create_sequence_builder it's in FASTDDS source code DynamicTypeBuilderFactory.cpp here

DynamicTypeBuilder* DynamicTypeBuilderFactory::create_sequence_builder(
        const DynamicType_ptr type,
        uint32_t bound)
{
    if (type != nullptr)
    {
        if (bound == BOUND_UNLIMITED)
        {
            bound = MAX_ELEMENTS_COUNT;
        }

Here BOUND_UNLIMITED macro is 0, MAX_ELEMENTS_COUNT macro is 100. For DynamicType , FASTDDS will set the bound to MAX_ELEMENTS_COUNT if the input bound is BOUND_UNLIMITED.

And finally at runtime. in FASTDDS source code DynamicData.cpp here

ReturnCode_t DynamicData::insert_sequence_data(
        MemberId& outId)
{
    outId = MEMBER_ID_INVALID;
    if (get_kind() == TK_SEQUENCE)
    {
        if (type_->get_bounds() == BOUND_UNLIMITED || get_item_count() < type_->get_bounds())
        {
        ...
        }
        else
        {
            logError(DYN_TYPES, "Error inserting data. The container is full.");
            return ReturnCode_t::RETCODE_BAD_PARAMETER;
        }
    }

Here type_->get_bounds() is MAX_ELEMENTS_COUNT, and if your item sequence size is bigger than it(for image the pixel data is definitely bigger than 100) , you will get an error "Error inserting data. The container is full."

I'm not sure my understanding is correct.. And is there an elegant way to handle this?