| 摘要 |
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.
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