client_db
Squid keeps a number of statistics for each cache client (IP address). You can
view them by visiting the cache manager
client_list page. The ClientInfo data structure is about 240 bytes
on 32-bit systems and 300 bytes on 64-bit systems. If you have
thousands of clients, this database can consume a significant amount
of memory. You can disable this directive and free up that memory for
other uses.