When stream event Join in WSO2 CEP each output event produsing two times - complex-event-processing

Question

I am using WSO2 CEP embedded inside the WSO2 DAS
For the following Execution plan
#Import('RelatedStream:1.0.0')
define stream rs (ID string, product string, uc1 string, state string, brand string, model string, type string, tweet string, rtID string);
#Import('InputStream:1.0.0')
define stream ins (ID string, product string, uc1 string, state string, brand string, model string, type string, tweet string);
#Export('matchingStream:1.0.0')
define stream ms (rID string, rproduct string, ruc1 string, rstate string, rbrand string, rmodel string, rtype string, hID string, hproduct string, huc1 string, hstate string, hbrand string, hmodel string, htype string);
from ins#window.time(2 sec) as R
join rs#window.length(1) as H
on R.product == H.product and R.brand==H.brand and R.type==H.type and R.model==H.model and R.state!=H.state and R.ID==H.rtID
select R.ID as rID, R.product as rproduct , R.uc1 as ruc1 , R.state as rstate, R.brand as rbrand , R.model as rmodel , R.type as rtype ,H.ID as hID , H.product as hproduct , H.uc1 as huc1 , H.state as hstate , H.brand as hbrand, H.model as hmodel , H.type as htype
insert all events into ms;
Every output event producing two times with same values
The Event Message Tracer log is below
Stream one (InputStream)
08:23:21,845 [-] [DataBridge-Core-pool-1-thread-3] INFO TenantId : -1234, Event Processor : R_H_Match, Event Stream : InputStream:1.0.0 (ins), before processing _Event{timestamp=1464144801440, data=[27, phone, g1, sell, samsung, galaxy note, type, Use UM10 to get 10% OFF #unlockyourphone Galaxy Note 6 will reportedly be the first Samsung phone to feature US... sell], isExpired=false} (Sanitized)
Stream two(RelatedStream)
08:23:21,974 [-] [DataBridge-Core-pool-1-thread-2] INFO TenantId : -1234, Event Processor : R_H_Match, Event Stream : RelatedStream:1.0.0 (rs), before processing _Event{timestamp=1464144801943, data=[5, phone, g1, sell, samsung, iphone 4s, type, White 3 USB Port Car Charger Adapter For iPhone 4S 5S 5C 6 6S iPad Samsung Phone - Bid Now? sell, 27], isExpired=false} (Sanitized)
08:23:21,998 [-] [DataBridge-Core-pool-1-thread-4] INFO TenantId : -1234, Event Processor : R_H_Match, Event Stream : RelatedStream:1.0.0 (rs), before processing _Event{timestamp=1464144801944, data=[11, phone, g1, buy, samsung, galaxy s4, type, #cellular #deals Samsung Galaxy S4 SCH-I545 16GB Verizon AT&T GSM UNLOCKED Cell Phone RF buy, 27], isExpired=false} (Sanitized)
08:23:22,030 [-] [DataBridge-Core-pool-1-thread-5] INFO TenantId : -1234, Event Processor : R_H_Match, Event Stream : RelatedStream:1.0.0 (rs), before processing _Event{timestamp=1464144801944, data=[13, phone, g1, sell, samsung, galaxy note, type, UNLOCKED T-Mobile Samsung Galaxy Note 3 SM-N900T 4G LTE GSM 32GB Smart Phone sell, 27], isExpired=false} (Sanitized)
08:23:22,031 [-] [DataBridge-Core-pool-1-thread-5] INFO TenantId : -1234, Event Processor : R_H_Match, Event Stream : RelatedStream:1.0.0 (rs), before processing _Event{timestamp=1464144801944, data=[18, phone, g1, sell, samsung, galaxy s6, type, Cell Phones : New Samsung Galaxy S6 Edge SM-G925F 5.1'' 16MP (FACTORY UNLOCKED) 32GB Phone sell, 27], isExpired=false} (Sanitized)
08:23:22,031 [-] [DataBridge-Core-pool-1-thread-5] INFO TenantId : -1234, Event Processor : R_H_Match, Event Stream : RelatedStream:1.0.0 (rs), before processing _Event{timestamp=1464144801944, data=[19, phone, g1, sell, samsung, galaxy s4, type, #cellular #deals Samsung i545 Galaxy S4 16GB Verizon 13MP Camera WiFi Cell Phone sell, 27], isExpired=false} (Sanitized)
08:23:22,031 [-] [DataBridge-Core-pool-1-thread-5] INFO TenantId : -1234, Event Processor : R_H_Match, Event Stream : RelatedStream:1.0.0 (rs), before processing _Event{timestamp=1464144801944, data=[1, phone, g1, sell, samsung, galaxy s6, type, Cell Phone USA : New Samsung Galaxy S6 Edge SM-G925F 5.1'' 16MP (FACTORY UNLOCKED) 32GB Ph? sell, 27], isExpired=false} (Sanitized)
08:23:22,033 [-] [DataBridge-Core-pool-1-thread-5] INFO TenantId : -1234, Event Processor : R_H_Match, Event Stream : RelatedStream:1.0.0 (rs), before processing _Event{timestamp=1464144801944, data=[14, phone, g1, sell, samsung, galaxy note, type, Galaxy Note 6 will reportedly be the first Samsung phone to feature USB-C - sell, 27], isExpired=false} (Sanitized)
08:23:22,034 [-] [DataBridge-Core-pool-1-thread-5] INFO TenantId : -1234, Event Processor : R_H_Match, Event Stream : RelatedStream:1.0.0 (rs), before processing _Event{timestamp=1464144801945, data=[16, phone, g1, buy, samsung, galaxy note, type, #unlocksquare Galaxy Note 6 will reportedly be the first Samsung phone to feature USB-C buy, 27], isExpired=false} (Sanitized)
08:23:22,035 [-] [DataBridge-Core-pool-1-thread-5] INFO TenantId : -1234, Event Processor : R_H_Match, Event Stream : RelatedStream:1.0.0 (rs), before processing _Event{timestamp=1464144801945, data=[17, phone, g1, buy, samsung, galaxy s5, type, Cell Phone USA : NEW T-Mobile Protective Cover/Holster For Samsung Galaxy S5 Case Kickstan? buy, 27], isExpired=false} (Sanitized)
08:23:22,035 [-] [DataBridge-Core-pool-1-thread-5] INFO TenantId : -1234, Event Processor : R_H_Match, Event Stream : RelatedStream:1.0.0 (rs), before processing _Event{timestamp=1464144801945, data=[15, phone, g1, buy, samsung, galaxy s6, type, Cell Phone USA : Samsung Galaxy S6 SM-G920F 32GB Unlocked 16MP Smartphone #4422 buy, 27], isExpired=false} (Sanitized)
Output Stream (matchingStream)
08:23:22,041 [-] [Siddhi-R_H_Match-executor-thread-1] INFO TenantId : -1234, Event Processor : R_H_Match, Event Stream : matchingStream:1.0.0 (ms), after processing _[Event{timestamp=1464144801945, data=[27, phone, g1, sell, samsung, galaxy note, type, 16, phone, g1, buy, samsung, galaxy note, type], isExpired=false}] (Sanitized)
08:23:22,120 [-] [Siddhi-R_H_Match-executor-thread-1] INFO TenantId : -1234, Event Processor : R_H_Match, Event Stream : matchingStream:1.0.0 (ms), after processing _[Event{timestamp=1464144802037, data=[27, phone, g1, sell, samsung, galaxy note, type, 16, phone, g1, buy, samsung, galaxy note, type], isExpired=false}] (Sanitized)

Answer 1

When you insert all events into the output event stream, it includes both current events (incoming events) and expired events (emitted by the windows after timing out or when window length is exceeded). Hence there is a possibility of getting duplicates.
If your requirement is to trigger an output using incoming events of 'rs' stream, you can try something like following: (with current events)
from ins#window.time(2 sec) as R
join rs#window.length(0) as H
on R.product == H.product and R.brand==H.brand and R.type==H.type and R.model==H.model and R.state!=H.state and R.ID==H.rtID
select R.ID as rID, R.product as rproduct , R.uc1 as ruc1 , R.state as rstate, R.brand as rbrand , R.model as rmodel , R.type as rtype ,H.ID as hID , H.product as hproduct , H.uc1 as huc1 , H.state as hstate , H.brand as hbrand, H.model as hmodel , H.type as htype
insert current events into ms;