Missed and duplicate events with Continues Query Cache

Question

We have seen missed events and duplicate events when we register to receive events (using Continues Query Cache) on an entry in the cache while the entry is updating.
Use case:
Start a Node
Start a Proxy
Start Extend Client
Implementation of the Extend Client
Create Cache
Add Entry to Cache
Initiate Thread 1 {
      For each ( 1 to 30)
          Run Update Entry Processor on cache entry; Entry Processor increments the Cache Entry value by 1 
Initiate Thread 2 {
     wait until Cache entry is updated 10 times
     Create MAP Listener {
          For Entry Insert Event {
                        Print event
               set Initial value = new value
          For Entry Update Event {
                        Print event
               set Update value = + 1
     Initiate Continues Query Cache (cache, Always Filter, MAP Listener)
Start Thread 1
Start Thread 2
Waits until Thread 1 and Thread2 are terminated
Expected Result = read the value of the entry from cache
Actual result = Initial value + Update value
Results we have seen in two tests_
Test1: Expected Result > Actual results: Missing events
Entry Inserted Event: MapEvent{ContinuousQueryCache inserted: key=1, value=UpdateObject [intNumber=1, longNumber=13]}
+Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=13], new value=UpdateObject [intNumber=1, longNumber=15]}+*
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=15], new value=UpdateObject [intNumber=1, longNumber=16]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=16], new value=UpdateObject [intNumber=1, longNumber=17]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=17], new value=UpdateObject [intNumber=1, longNumber=18]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=18], new value=UpdateObject [intNumber=1, longNumber=19]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=19], new value=UpdateObject [intNumber=1, longNumber=20]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=20], new value=UpdateObject [intNumber=1, longNumber=21]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=21], new value=UpdateObject [intNumber=1, longNumber=22]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=22], new value=UpdateObject [intNumber=1, longNumber=23]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=23], new value=UpdateObject [intNumber=1, longNumber=24]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=24], new value=UpdateObject [intNumber=1, longNumber=25]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=25], new value=UpdateObject [intNumber=1, longNumber=26]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=26], new value=UpdateObject [intNumber=1, longNumber=27]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=27], new value=UpdateObject [intNumber=1, longNumber=28]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=28], new value=UpdateObject [intNumber=1, longNumber=29]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=29], new value=UpdateObject [intNumber=1, longNumber=30]}
Expected Result: 30
Actual Result: 29
Issue:+ Event on 14th update was not sent
Test 2: Expected Result < Actual Result: Duplicate events
Entry Inserted Event: MapEvent{ContinuousQueryCache inserted: key=1, value=UpdateObject [intNumber=1, longNumber=13]}
*Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=13], new value=UpdateObject [intNumber=1, longNumber=13]}*+
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=13], new value=UpdateObject [intNumber=1, longNumber=14]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=14], new value=UpdateObject [intNumber=1, longNumber=15]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=15], new value=UpdateObject [intNumber=1, longNumber=16]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=16], new value=UpdateObject [intNumber=1, longNumber=17]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=17], new value=UpdateObject [intNumber=1, longNumber=18]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=18], new value=UpdateObject [intNumber=1, longNumber=19]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=19], new value=UpdateObject [intNumber=1, longNumber=20]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=20], new value=UpdateObject [intNumber=1, longNumber=21]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=21], new value=UpdateObject [intNumber=1, longNumber=22]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=22], new value=UpdateObject [intNumber=1, longNumber=23]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=23], new value=UpdateObject [intNumber=1, longNumber=24]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=24], new value=UpdateObject [intNumber=1, longNumber=25]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=25], new value=UpdateObject [intNumber=1, longNumber=26]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=26], new value=UpdateObject [intNumber=1, longNumber=27]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=27], new value=UpdateObject [intNumber=1, longNumber=28]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=28], new value=UpdateObject [intNumber=1, longNumber=29]}
Entry Updated Event: MapEvent{ContinuousQueryCache updated: key=1, old value=UpdateObject [intNumber=1, longNumber=29], new value=UpdateObject [intNumber=1, longNumber=30]}
Expected Result: 30
Actual Result: 31
Issue:+ Event on 13th update was sent in Insert and Update events both
reg
Dasun.

Answer 1

Hi Paul,
I tested with 3.7.1.4 and 3.7.1.5. In both versions I can see the issue.
reg
Dasun.