🔗 How modern indexing works in PostgreSQL

Indexing is crucial for fast data retrieval in Database Management Systems. PostgreSQL employs efficient indexing methods that aren't just theoretical but practical. A significant feature is how it handles both clustered and non-clustered indexing. Unlike MySQL, which only supports non-clustered indexes as separate files, PostgreSQL treats all indexing types similarly, optimizing memory usage by scanning and sorting data based on the specified keys.

During the indexing process, when a query is executed, PostgreSQL scans data, organizing it into an efficient structure. For example, creating an index on user emails involves generating a sorted index file based on the email addresses. When a search query is made, PostgreSQL retrieves data directly from this index, streamlining the process considerably. The latest advancements, like io_uring, further enhance this efficiency by optimizing how these disk calls are made, making the indexing process modern and highly responsive.