Method for controlling near caches in distributed cache environment, and distributed cache server using the same

A method for controlling one or more near caches in a distributed cache environment which includes a plurality of distributed cache servers, comprising steps of:

• (a) a specific distributed cache server among the plurality of distributed cache servers, if a request signal for original cache data is obtained from at least one client node, (i) transmitting replicated cache data for the original cache data to the at least one client node, to thereby support the at least one client node to store and refer to the replicated cache data in its corresponding near cache storage part, and (ii) generating or updating or supporting another device to generate or update a reference map which has mapping information between the at least one client node referring to the replicated cache data and the original cache data;
• (b) the specific distributed cache server monitoring or supporting another device to monitor a changed state of the original cache data included in the reference map, to thereby check a validity of the replicated cache data;
• and
• (c) the specific distributed cache server, if the replicated cache data is determined as not valid, checking or supporting another device to check the number of the client nodes currently referring to the replicated cache data by referring to the reference map, and invalidating or supporting another device to invalidate the replicated cache data according to the number of the checked client nodes.