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I proposed that the recursive SQL to fetch descendants be implemented first as an independent change, as it move worst-case complexity from O(N2) to O(N). By contrast, the query using path-component look-up will improve best-case performance from O(N) to O(1).
Cps Path Parser changes
The PoC uses String.split for parsing path components, which means paths containing '/' in the leaf condition are not parsed correctly, such as //books[@title='GNU/Linux']. CpsPathBuilder and CpsPathQuery classes from cps-path-parser module will need to be updated to provide the individual path components (in normalized form).
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