Misc UaSubscription Questions

[peterfranciscook]

// (milo 0.6.16)
artifacts = [
"org.eclipse.milo:sdk-client:0.6.16",
"org.eclipse.milo:stack-core:0.6.16",
"org.eclipse.milo:stack-client:0.6.16",
],

Question 1: Is the sequencing of client handles important? i.e. Does it make a speed/memory difference on the client side if I use what would appear to be unordered handles versus a monotonic list of integers? I have some "legacy" code to generate client handles that stuffs 2 bytes and a short into the handle.

int buildClientHandle(int ns, int idx, int nid) {
    return (ns << 24) | (idx << 16) | (nid & 0x0000FFFF);
}

I used to unpack this client handle in the ValueConsumer onValueArrived callback to know where to dispatch the data, and used it as a hashtable key for dispatching subscriptions because I thought that hash collisions were causing problems with using NodeId as a hashtable key directly (but turns out I just didn't fully understand how Java handles duplicate hashes in its Map implementations). Currently considering eliminating this path for generating client handles and just using UaSubscription::nextClientHandle, but wondering if it even matters...

Question 2: Is it necessary to manually cleanup subscriptions when I close the client connection? I am wondering if my shutDown sequence is redundant:

[kevinherron]

Question 1: Is the sequencing of client handles important? i.e. Does it make a speed/memory difference on the client side if I use what would appear to be unordered handles versus a monotonic list of integers?

No, all that matters is they uniquely identify a MonitoredItem within the context of a Subscription. The client handle is the key used to identify the MonitoredItem a notification from the server belongs to.

Question 2: Is it necessary to manually cleanup subscriptions when I close the client connection? I am wondering if my shutDown sequence is redundant:

No, if the client is properly shut down (OpcUaClient::disconnect) the Session is closed, and the CloseSessionRequest is sent with the deleteSubscriptions parameter set to true.