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SELECT * FROM fragment WHERE anchor_id = ? AND xpath IN (?,?,?,?,?,?...,?)
SELECT * FROM fragment WHERE anchor_id = ? AND xpath IN (?,?,?,?,?,?...,?)
SELECT * FROM fragment WHERE anchor_id = ? AND xpath IN (?,?,?,?)

Observations

Disadvantage: public API signatures may need to be changed

If a public method takes in a Collection (and not a List), then either an ArrayList copy of the Collection is needed, or the public API method needs to be changes to List, as Lists.partition requires a List to partition.

Proposal #2: Postgres arrays

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It is unclear if this has better performance in practice (limited testing shows both solutions have similar performance, but the test scenarios may be unrealistic).

Observations

Disadvantage of arrays: Limited array type support

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