Phase 3: Query Performance & Infrastructure Diagnostics #8
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- Statistical index bloat estimation using pg_class/pg_stats (ioguix-style) - Table bloat from dead tuple ratios via pg_stat_user_tables - Status thresholds: 20% warning, 50% critical - Recommendations for VACUUM FULL and REINDEX when critical - Full JSON support with pgcrate.diagnostics.bloat schema - Added diagnostics.bloat capability check - Integration tests for empty DB, tables, JSON structure, limit option
Use chars().count() and chars().take() instead of byte slicing to avoid panic on multi-byte UTF-8 characters in table/index names.
- Server role detection (primary vs standby via pg_is_in_recovery()) - Replica lag monitoring from pg_stat_replication (write, flush, replay lag) - Replication slot status from pg_replication_slots (active, wal_status, retained) - WAL receiver info on standby servers from pg_stat_wal_receiver - Status thresholds: - Warning: replay_lag >30s or inactive slot retaining >1GB - Critical: replay_lag >5min or wal_status='lost' or slot retaining >10GB - Full JSON support with pgcrate.diagnostics.replication schema - Added diagnostics.replication capability (degraded if no pg_stat_replication access) - Integration tests for standalone server (no replica) scenarios
Bug fixes: - Fix UTF-8 slicing in sequences.rs display (same issue as bloat.rs) - Fix xid_age type overflow in triage.rs (i32 -> i64 for large XID ages) - Add better error context in xid.rs for empty database handling - Align triage sequences check with sequences.rs (consistent float calculation) UX improvements: - Add 'migration' as visible alias for 'migrate' command - Add 'create' as visible alias for 'migrate new' command These fixes address issues reported in 25+ agent feedback sessions.
Bug Fixes: - UTF-8 string slicing in bloat/sequences (prevents panic on non-ASCII) - XID age type overflow in triage (i32 → i64) - Triage sequences percentage calculation alignment - Better error context for XID on empty databases UX Improvements: - Add 'migration' as alias for 'migrate' command - Add 'create' as alias for 'migrate new' command
Completes the "why is prod slow?" workflow with: pgcrate queries: - Top queries from pg_stat_statements by total time, mean time, or calls - Cache hit ratio per query - Status thresholds: warning >1s mean, critical >5s mean - Graceful degradation when extension not installed - JSON output with pgcrate.diagnostics.queries schema pgcrate connections: - Connection usage vs max_connections with percentage - Breakdown by state (active, idle, idle in transaction) - Group by user, database, or application - Status thresholds: warning >75%, critical >90% - JSON output with pgcrate.diagnostics.connections schema Updated capabilities: - diagnostics.queries: available when pg_stat_statements installed - diagnostics.connections: always available (uses pg_stat_activity)
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Summary
Complete diagnostic suite for production PostgreSQL performance analysis:
Phase 3a: Query Performance Diagnostics
pgcrate queries: Top queries from pg_stat_statementspgcrate connections: Connection usage analysisPhase 3b: Infrastructure Diagnostics
pgcrate bloat: Table and index bloat estimationpgcrate replication: Streaming replication healthBug Fixes
UX Improvements
migrationalias formigratecommandcreatealias formigrate newcommandTest plan
pgcrate queriesgracefully handles missing pg_stat_statementspgcrate connectionsshows accurate usage vs max_connectionspgcrate bloatestimates without extensionspgcrate replicationdetects server role correctly