Hi @filipniziol 
Thanks for your reply 
My issue is resolved as my fellow developer ran same commands with different name after sometime it worked successfully.
FYI - 
I was running query in same notebook just in different cells also I was running cells simultaneously so session based scope of temporary view should not be problem I believe as I previously mentioned I was able to see data in temp view
Also about merge conditions as I mentioned I tested that on dummy table so it was also working fine 
I used following merge query type

MERGE INTO <table name>
USING <query as view> 
   ON <primary key equality> 
WHEN MATCHED THEN UPDATE SET * 
WHEN NOT MATCHED THEN INSERT  

 
My observation - As I was working on gathering data had performed several operations in single notebook it get usually warning of larger notebook size and save session etc ,
I am suspecting that may be the cause of this error but still not 100% sure about it as I also ran tempview and merge query in new notebook in last time that also failed yesterday