A new multiattribute index structure called the hB-tree is introduced. It is derived from the K-D-Btree of Robinson [15] but has additional desirable properties. The hB-tree internode search and growth processes are precisely analogous to the corresponding processes in B-trees [l]. The intranode processes are unique. A k-d tree is used as the structure within nodes for very efficient searching. Node splitting requires that this k-d tree be split. This produces nodes which no longer represent brick-like regions in k-space, but that can be characterized as holey bricks, bricks in which subregions have been extracted. We present results that guarantee hB-tree users decent storage utilization, reasonable size index terms, and good search and insert performance. These results guarantee that the hB-tree copes well with arbitrary distributions of keys.
We present an access method designed to provide a single integrated index structure for a versioned timestamped database with a non-deletion policy. Historical data (superceded versions) is stored separately from current data. Our access method is called the TimeSplit B-tree. It is an index structure based on Malcolm Easton's Write Once B-tree.The Write Once B-tree was developed for data stored entirely on a Write-Once Read-Many or WORM optical disk. The Time-Split B-tree differs from the Write Once B-tree in the following ways: l Current data must be stored on an erasable randomaccess device. l Historical data may be stored on any random-access device, inciuding WORMS, erasable optical disks, and magnetic disks. The point is to use a faster and more expensive device for the current data and a slower cheaper device for the historical data. l The splitting policies have been changed to reduce redundancy in the structure-the option of pure key splits as in B+-trees and a choice of split times for time-based splits enable this performance enhancement. l When data is migrated from the current to the historical database, it is consolidated and appended to the end of the historical database, allowing for high space utilization in WORM disk sectors.
We present an access method designed to provide a single integrated index structure for a versioned timestamped database with a non-deletion policy. Historical data (superceded versions) is stored separately from current data. Our access method is called the TimeSplit B-tree. It is an index structure based on Malcolm Easton's Write Once B-tree.The Write Once B-tree was developed for data stored entirely on a Write-Once Read-Many or WORM optical disk. The Time-Split B-tree differs from the Write Once B-tree in the following ways: l Current data must be stored on an erasable randomaccess device. l Historical data may be stored on any random-access device, inciuding WORMS, erasable optical disks, and magnetic disks. The point is to use a faster and more expensive device for the current data and a slower cheaper device for the historical data. l The splitting policies have been changed to reduce redundancy in the structure-the option of pure key splits as in B+-trees and a choice of split times for time-based splits enable this performance enhancement. l When data is migrated from the current to the historical database, it is consolidated and appended to the end of the historical database, allowing for high space utilization in WORM disk sectors.
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