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teaching:projh402 [2020/10/03 16:16] ezimanyi [K-D-Tree Indexes for MobilityDB] |
teaching:projh402 [2020/10/03 17:50] ezimanyi [VODKA Indexes for MobilityDB] |
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===== VODKA Indexes for MobilityDB ===== | ===== VODKA Indexes for MobilityDB ===== | ||
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+ | MobilityDB implemented [[https://habr.com/en/company/postgrespro/blog/444742/|GiST]] and [[https://habr.com/ru/company/postgrespro/blog/446624/|SP-GiST]] indexes for temporal types. These indexes are based on bounding boxes, that is, inner or leaf levels of the indexes store a bounding box that keeps the mininum and maximum values of each of the dimensions X, Y, Z (if available) and T where X, Y, Z are for the spatial dimension and T for the temporal dimension. The reason for this is that a temporal type (for example, a moving point representing the movement of a vehicle) can have thousands of timestamped points and keeping all these points for each vehicle indexed in a table is very inefficient. By keeping the bounding box only, it is possible to quickly filter the rows in a table and then a more detailed analysis can be made for those rows selected by the index. | ||
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