Symptoms
This issue occurs when you enable a query that reads committed snapshot isolation with clustered columnstore index (CCI).
Cause
This issue occurs because an undetected deadlock occurs in a lock, in mutex, and in the parallel query.
Resolution
Cumulative update information
The issue was first fixed in the following cumulative update for Microsoft SQL Server 2014:
Cumulative Update 4 for SQL Server 2014 SP1
Recommendation Install the latest cumulative update for SQL Server
