Follow-up to the previous two commits: the ALTER DATABASE ... SET
autovacuum_* commands fail at boot with
ERROR: parameter "autovacuum_vacuum_scale_factor" cannot be changed now
and take matrix-synapse-db-tune.service (and nextcloud-db-init.service)
down with them.
Root cause: ALTER DATABASE/ROLE ... SET validates through
set_config_option() with an interactive context, and guc.c rejects any
PGC_SIGHUP parameter set that way. All autovacuum_* GUCs are
SIGHUP-context, so per-database scoping is impossible for them — only
USERSET-level parameters (e.g. work_mem, statement_timeout) can be set
per-database.
Nothing is lost: the same values are already set cluster-wide in
configuration.nix, which covers both nextclouddb and matrix-synapse.
Remove the ALTERs from nextcloud-db-init and delete the now-purposeless
matrix-synapse-db-tune service.
Monolith Synapse spends most of its RAM on caches to avoid Postgres
round-trips, but Sovran ships stock cache settings (global_factor 0.5,
10K event cache, no autotuning) and a default 5-connection DB pool.
- caches.global_factor 4.0 + 100K event cache + autotuning capped at
2G (target 1G), with boosts for the /sync and room-join hot paths.
- DB pool cp_min 5 / cp_max 15, txn_limit 10000 (fewer reconnects).
- gc_thresholds raised to cut GC pauses on a 32 GB box.
- cache-memory extra for cache-size statistics.
- Per-database autovacuum (ALTER DATABASE, scoped to matrix-synapse)
matching the nextclouddb tuning.
Deliberately unchanged: presence and URL previews stay enabled
(disabling them is faster but user-visible), and no workers — monolith
is the right call under ~100 users. Workers would need Redis
replication, the redis extra, and Caddy reverse-proxy rework; revisit
if federation load ever justifies it.
- modules/synapse.nix: replace tr|head pipeline (causes SIGPIPE under
set -euo pipefail) with pwgen -sA0 20 1 which is already in PATH
- modules/bitcoin/rtl.nix: lowercase Authentication->authentication and
Settings->settings per RTL v0.15.8 schema; add lnServerUrl pointing
to LND REST endpoint; move swapServerUrl/boltzServerUrl inside
settings; apply same fixes to CLN branch
Co-authored-by: naturallaw777 <99053422+naturallaw777@users.noreply.github.com>
Sovran Contributor
copilot-swe-agent[bot]andnaturallaw777
naturallaw777