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PostgreSQL is an open-source relational database management system known for its extensibility, which allows developers to enhance its capabilities through various extensions and plugins. The pgstattuple extension provides detailed statistics at the tuple level from PostgreSQL tables and indexes, revealing key metrics such as the number of live tuples, dead tuples, average length of live tuples, total free space, and percentages of free space and dead tuples. These metrics help database administrators identify potential health and performance issues, such as excessive table bloat or index fragmentation. Both Amazon Aurora and Amazon RDS support the pgstattuple extension, which can be activated using the command CREATE EXTENSION pgstattuple;. Functions like pgstattuple(relation) and pgstatindex(index) can be used to analyze physical storage and index statistics. Bloat occurs when unused space is left behind after UPDATE and DELETE operations, and the autovacuum process in PostgreSQL automates the cleanup of dead tuples. However, if autovacuum fails, manual intervention may be necessary. Regular monitoring of bloat is essential for maintaining performance, and metrics from pgstattuple can help optimize autovacuum settings. The pg_cron extension can automate VACUUM operations to manage bloat proactively. Index bloat can also be detected using pgstatindex, and significantly bloated indexes can be rebuilt using REINDEX or pg_repack. Best practices for using pgstattuple include estimating bloat with check_postgres, analyzing physical storage, monitoring dead_tuple_percent, and avoiding interference on highly active tables.