The image shows two boxes:

• Initial state (True Cache is available)
  • Read-write data flows back and forth between application 1 and the primary database.
  • Occasional read-write data flows back and forth between application 2 and the primary database.
  • Read-only data flows back and forth between application 2 and True Cache.
  • Infrequent read-only data flows back and forth between application 1 and True Cache.
• True Cache unavailable
  • Read-write and infrequent read-only data flow back and forth between application 1 and the primary database.
  • Occasional read-write data and read-only data flow back and forth between application 2 and the primary database.
  • No data flows to True Cache because it's unavailable.