Function mixNormalizedKey

bolt/exec/HashTable.cpp:554–556

Normalized keys have non0-random bits. Bits need to be propagated up to make a tag byte and down so that non-lowest bits of normalized key affect the hash table index.

// up to make a tag byte and down so that non-lowest bits of
// normalized key affect the hash table index.
inline uint64_t mixNormalizedKey(uint64_t k, uint8_t bits) {
  return folly::hasher<uint64_t>()(k);
}

void populateNormalizedKeys(HashLookup& lookup, int8_t sizeBits) {
  lookup.normalizedKeys.resize(lookup.rows.back() + 1);