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Hash partitioning previously relied on coercing (casting) values to strings before calculating a hash value, including creating CHECK constraints with casts. This approach is fairly suboptimal from a performance perspective and might have issues related to different character encodings depending on system. Hash partitioning now instead uses a partitioning function that takes an anyelement type that calls type-dependent hash functions internal to PostgreSQL. This should provide more efficient hashing both by avoiding unnecessary string conversions and by using more optimal type-specific hash functions. Support for the previous hash partitioning function is preserved for backwards compatibility. Hypertables created with the previous function will continue to use to old hashing strategy, while new tables will default to the updated hash partitioning. For safety, this change also blocks changing types on hash-partitioned columns, since it seems hard to guarantee the same hash result between different types.