Explain the differences between hash indexes and B-Tree indexes in PostgreSQL database.

In PostgreSQL, there are different types of indexes, among which hash indexes and B-Tree indexes are the most common.

B-Tree indexes:

• Used by default for most data types.
• Support comparison operations: equality, range (>, <, BETWEEN).
• The tree structure allows for fast searching, inserting, and deleting records.
• Well-suited for sorting and range searches.

Hash indexes:

• Optimized only for equality operations (=).
• Use a hash function for quick lookup.
• Do not support range searches.
• Previously in PostgreSQL, they were less reliable and did not support WAL (transaction log), but the situation has improved in newer versions.