feat(cli): implement F004 and F005 bloat estimation checks

Summary

Implement heap and index bloat estimation for express mode checkup.

New Checks

F004 - Autovacuum: heap bloat estimate

  • Estimates table bloat using pg_stats column statistics
  • Returns top 100 tables by bloat size (>= 1 MiB)
  • Shows real size, extra size, bloat percentage, fillfactor

F005 - Autovacuum: index bloat estimate

  • Estimates B-tree index bloat using pg_stats
  • Returns top 100 indexes by bloat size (>= 1 MiB)
  • Shows real size, table size, bloat percentage, fillfactor

Implementation Notes

  • Uses standard pg_stats view (no special extensions required)
  • Based on well-known bloat estimation algorithms
  • Excludes system schemas (pg_catalog, information_schema, pg_toast)
  • Minimum size threshold of 1 MiB to focus on meaningful bloat

Related

Acceptance Criteria

  • F004 (heap bloat estimate) uses pg_stats column statistics to estimate table bloat without requiring special extensions
  • F005 (index bloat estimate) estimates B-tree index bloat using pg_stats
  • Both reports return the top 100 objects sorted by bloat size with a minimum threshold of 1 MiB
  • Reports include: real size, extra size (estimated bloat), bloat percentage, and fillfactor for each object
  • System schemas (pg_catalog, information_schema, pg_toast) are excluded from results

Definition of Done

  • MR !180 (merged) merged
  • Bloat estimates validated against known bloated tables (compare with pgstattuple extension results if available)
  • Reports work across PostgreSQL 13-17
  • JSON output follows existing checkup report conventions
Edited by Nikolay Samokhvalov