DOC-5275 Added an example of a DB temporarily exceeding its memory limit

Author: rrelledge

content/operate/rs/databases/memory-performance/memory-limit.md

@@ -71,6 +71,10 @@ You must maintain sufficient free memory to make sure that you have a healthy Re
 
 In rare cases during high-velocity data ingestion, databases can temporarily reach up to 200% of their configured memory limit. This adaptive memory allocation strategy allows large amounts of data to be written to the database quickly without rejecting valid transactions.
 
+For example, when pushing data at approximately 100 MB/sec into a 2 GB database:
+- A database with 2 shards could reach 199% of its configured memory limit.
+- A database with 4 shards could reach around 220% of its configured memory limit.
+
 Databases should return to their configured memory limits after data is removed according to the [eviction policy]({{<relref "/operate/rs/databases/memory-performance/eviction-policy/">}}) and [time-to-live (TTL)]({{<relref "/develop/using-commands/keyspace#key-expiration">}}).
 
 If you observe this behavior, consider [monitoring]({{< relref "/operate/rs/monitoring/" >}}) memory usage and controlling the traffic load on the application side.