PostgreSQL 18 on Amazon Aurora and Amazon RDS: Security, monitoring, and developer enhancements

Part 2 of the PostgreSQL 18 series focuses on security and operational improvements on Amazon Aurora and Amazon RDS, including deprecation of MD5 password authentication in favor of SCRAM-SHA-256, enhanced parallel worker monitoring via new columns in pg_stat_database and pg_stat_statements, and logical replication conflict tracking. It also covers optimizer statistics preservation during upgrades, the new uuidv7() function for sortable IDs, parallel streaming as the default for logical replication, and COPY command enhancements including REJECT_LIMIT and OLD/NEW aliases in RETURNING clauses.