Is the Read Uncommitted isolation level supported in PostgreSQL?

In PostgreSQL, the Read Uncommitted transaction isolation level is not supported directly. The lowest isolation level implemented in PostgreSQL is Read Committed.

Read Committed guarantees that a transaction only sees data that has been committed by other transactions at the time of the query. This prevents reading "dirty" (uncommitted) data.

If a more strict isolation is needed, Repeatable Read or Serializable can be used.

Therefore, PostgreSQL does not have a separate Read Uncommitted level, as the database architecture and MVCC (multi-version concurrency control) make this isolation level redundant.