Abstract: Provided is a method for managing a shared memory in a database server. The database server includes a shared memory manager which divides a shared memory into a plurality of memory chunks to manage the memory chunks and allocates at least one memory chunk to a cache memory manager based on a request of the cache memory manager; a cache memory manager which requests at least one of the plurality of memory chunks to the shared memory manager, wherein the database server includes a plurality of cache memory managers and the database server uses the memory chunk which is allocated to the cache memory manager as a cache memory having a predetermined purpose, and the predetermined purposes of the plurality of cache memory managers are different from each other; and a main processor which performs a database operation using the cache memory.

Abstract: According to an embodiment of the present invention, a computer program stored in a computer-readable medium for encrypting a data value included in a data table stored in a memory and storing the encrypted data value in a persistent storage medium is disclosed. The computer program allows a computer to perform steps including: generating an encrypted data value based on the data value included in the data table stored in a memory; generating a hash value that matches the encrypted data value at least partially based on the data value and positional information of the data value; and determining to write the encrypted data value and the hash value on a persistent storage medium.

Abstract: A data compression apparatus generates a global symbol table for an overlapping data using a part of the entire data to be compressed and a local symbol table that is not overlapped with the global symbol table and compressing data with a block as a unit. The apparatus increase compression efficiency.