Join-tree Generation (cont)
Genetic query optimiser (geqo ):
- uses genetic algorithm (GA) to generate path trees
- based on GA designed for "travelling salesman" problem
- goals of this approach:
- find near-optimal solution
- examine far less than entire search space
- used as path generator in PostgreSQL for large joins
- threshold determined by
geqo_threshold config param
Code in: backend/optimizer/geqo/*.c
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