Part of code-oflt (cut sdc write IOPS before the SSD move; analysis #6922).
- archive_timeout 300->0: CNPG forces archive_mode=on but .spec.backup is empty
(no ObjectStore), so a 16MB WAL segment switch every 5min shipped NOWHERE =
~4.6 GB/day of pure-waste WAL on the contended sdc. archive_mode stays CNPG-on
(reserved); 0 just stops the timed switch. Daily pg_dump cron unchanged.
- commit_delay 0->2500us: group-commit coalesces concurrent fsyncs. SAFE for
every DB incl financial -- data still fsynced before COMMIT acks, only <=2.5ms
added latency under concurrency.
- wal_compression pglz->zstd: ~30-50% smaller full-page images.
All sighup-reloadable. Applied via targeted apply of
module.dbaas.null_resource.pg_cluster (trigger bumped) to avoid the pre-existing
mysql VCT drift that breaks broad dbaas applies.
Refs: code-oflt.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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