The EOS Large Object Manager

Large objects are used in many unconventional database applications; pictures, digitized video and sound recordings are a few examples of large objects that need to be stored in a database. This paper discribes the large object manager of the EOS object store. We present the storage structures and algorithms used for the efficient manipulation of general-purpose large unstructured objects. The large object is stored in a sequence of variable-size segments, each of which consists of a large number of physically contiguous disk blocks. Disk space management is based on the binary buddy system. The scheme supports operations that replace, insert, delete bytes at arbitrary positions within the object, and append bytes at the end of the object. We analyze the performance of our scheme and compare it with the corresponding ones employed in two other experimental database storage systems. Keywords: database storage organization, object-oriented databases, computer-aided design, mul..