Abstract: The present invention discloses devices including a transparent client-connection manager for exchanging client data between application servers and the device: a request analyzer for analyzing query requests from at least one application server; a data-retrieval/command-execution module for executing query requests; a database connection manager for exchanging database data between at least one database server and the device; a cache-memory pool for storing data items from at least one database server; a cache-policy module for determining cache criteria for storing the data items In the cache-memory pool; and a data-consistency invalidation module for determining invalidated data items based on invalidation criteria for removing from the cache-memory pool. The cache-memory pool is configured to utilize memory modules residing in data proxy devices and distributed cache management utility, enabling the memory capacity to be used as a cluster to balance workloads.