PING
          
        
        
        
        
        
        
        Syntax
        PING [message]
- Available since:
 - Redis Open Source 1.0.0
 - Time complexity:
 - O(1)
 - ACL categories:
 - 
              
                
@fast,@connection, 
Returns PONG if no argument is provided, otherwise return a copy of the
argument as a bulk.
This command is useful for:
- Testing whether a connection is still alive.
 - Verifying the server's ability to serve data - an error is returned when this isn't the case (e.g., during load from persistence or accessing a stale replica).
 - Measuring latency.
 
If the client is subscribed to a channel or a pattern, it will instead return a multi-bulk with a "pong" in the first position and an empty bulk in the second position, unless an argument is provided in which case it returns a copy of the argument.
Examples
Return information
Any of the following:
- Simple string reply: 
PONGwhen no argument is provided. - Bulk string reply: the provided argument.