migrations: durable aggressive autovacuum for telemetry tables#89
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The telemetry DB grew to 77 GB of dead-tuple bloat. The 7-day retention prune deletes rows fine, but at Postgres' default 20% autovacuum scale factor, autovacuum effectively never fired on the high-churn tables (logs, metric_series_rollups, spans): their insert+delete churn never crossed the 20%-of-table threshold, so dead tuples were never reclaimed. Lower the vacuum (and insert-triggered vacuum) scale factor to 2% and raise the cost limit so autovacuum keeps up with the prune's delete churn. These settings were already applied live via ALTER TABLE; this migration makes them durable across a DB recreate. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_013cYVqzH7Xfwea7fAozdQK7
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Why
The watcher telemetry DB grew to 77 GB of dead-tuple bloat. The 7-day retention prune deletes rows fine, but at Postgres' default 20% autovacuum scale factor, autovacuum effectively never fired on the high-churn tables
logs,metric_series_rollups, andspans: their steady insert+delete churn never crossed the 20%-of-table threshold before the table itself had grown, so dead tuples were never reclaimed.What
New migration
0013_telemetry_autovacuum.sqlsets aggressive per-table autovacuum on the three telemetry tables:autovacuum_vacuum_scale_factor = 0.02— vacuum at 2% dead tuples instead of 20%autovacuum_vacuum_insert_scale_factor = 0.02— same for insert-triggered vacuumautovacuum_vacuum_cost_limit = 2000— let each run make real progress instead of throttlingThese were already applied live via
ALTER TABLE, but that's imperative and wouldn't survive a DB recreate. This migration makes the tuning durable.Notes
logsandspans(0001_init.sql),metric_series_rollups(0007).🤖 Generated with Claude Code
https://claude.ai/code/session_013cYVqzH7Xfwea7fAozdQK7