Improve query performance with a forest of trees index

A forest of trees index is an alternate indexing method that alleviates the performance bottlenecks and root node contention that can occur when many concurrent users access a traditional B-tree index.

A forest of trees index differs from a B-tree index in that it has multiple root nodes and fewer levels. Multiple root nodes can alleviate root node contention, because more concurrent users can access the index.

If you know that a particular table has a deep tree, you can improve performance by creating a forest of trees index with fewer levels in the tree. For example, suppose you create an index where one of the columns is a 100 byte column containing character data. If you have a large number of rows in that table, the tree might contain six or seven levels. If you create a forest of trees index instead of a B-tree index, you can create more than one tree with four levels, so that every index traversal goes only four levels deep rather than seven levels deep.


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