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🗓️ 27012025 0105

HASH INDEXES

Hash table stored on disk (or in memory) where a hash function maps a key to a file location

Strengths​

  • Fast key-value lookups (O(1))
  • Easy to implement.

Weaknesses​

  • Not good for range queries (e.g., finding all keys between 1 and 100 requires scanning the whole table)
  • Can waste space due to hash collisions (though techniques like chaining or open addressing help).

Example Usage​

Used in simple key-value stores where range queries aren't important.

References​

  • DDIA Chapter 3
  • ChatGPT