Multi-d Trees in PostgreSQL
Up to version 8.2, PostgreSQL had an R-tree implementation
Superseded by GiST = Generalized Search Trees
GiST indexes parameterise: data type, searching, splitting
- via seven user-defined functions (e.g.
picksplit() )
GiST trees have the following structural constraints:
- every node is at least fraction f full (e.g. 0.5)
- the root node has at least two children (unless also a leaf)
- all leaves appear at the same level
Details: src/backend/access/gist
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