US 5,845,296 A · Method and apparatus for implementing segmented arrays in a database

Abstract

A method and apparatus for implementing segmented arrays in a database system. According to one embodiment of the invention, rather than allocating a contiguous block of memory for each array, the memory for storing at least selected arrays is broken into smaller pieces of memory referred to herein as memory segments. When the memory for an array is broken into memory segments, the array is referred to herein as a "segmented array." Each memory segment associated with a segmented array is divided into one or more memory areas, each of which represent an element of that array. The memory segments associated with a segmented array need not be contiguous. According to another aspect of the invention, the number of segments allocated for a segmented array can be increased or decreased during execution. According to yet another aspect of the invention, only some of the memory segments required to store a segmented array are initially allocated. The remainder of the memory segments required to store the array are allocated on an as needed basis. According to another aspect of the invention, database systems may implement all or only some arrays as segmented arrays. In a database system that supports both segmented and contiguous arrays, whether the memory for a particular array is segmented or contiguous can depend on any number of factors.

Claims17

Dependent claims

A method for allocating memory in a database system, said method comprising the computer-implemented steps of:

detecting that an array for storing information related to said database system is required, wherein said array includes a plurality of elements;
determining that a first amount of memory is required to store said array;
determining that a set of one or more memory segments is to be allocated for said array, wherein each memory segment in said set of one or more memory segments is smaller than said first amount of memory;
allocating said set of one or more memory segments, wherein said set of one or more memory segments need not be contiguous, wherein each of said set of one or more memory segments includes a set of one or more memory areas, and wherein each memory area in each of said sets of one or more memory areas is for storing data associated with a different element of said array;
and
storing in a segment header memory area data for identifying said set of one or more memory segments.

3 more elements

A method for allocating memory in a database system, said method comprising the computer implemented steps of:

detecting that an array is required, wherein said array includes a set of one or more elements;
determining whether a predetermined condition is satisfied;
if said predetermined condition is satisfied, then allocating a contiguous block of memory for the storage of said array;
and
if said predetermined condition is not satisfied, then performing the steps of:
allocating a set of one or more memory segments for the storage of said array, wherein said set of one or more memory segments is not contiguous, wherein each of said set of one or more memory segments includes a set of one or more memory areas, and wherein each memory area in each of said sets of one or more memory segments is for storing data associated with a different element of said array;
and
storing data, wherein said data identifies said set of one or more memory areas in each memory segment of said set of one or more memory segments.

5 more elements

Dependencies are inferred from the claim text.

Method and apparatus for implementing segmented arrays in a database

Life of this patent

Method and apparatus for implementing segmented arrays in a database

Life of this patent

Abstract

Claims17