Postgres memory for the freed RAM: shared_buffers 8GB, effective_cache_size 32GB, random_page_cost 1.1, work_mem 16MB

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

deploy/compose.yaml

@@ -46,19 +46,31 @@ services:
       # waited on it (WALWrite, 56–70 ms a write with the HDD 100% busy; LOG.md 2026-10-13 (43)).
       - ${PG_WAL_DIR:-/var/lib/usenet-rebuild-wal}:/var/lib/postgresql/wal
     # synchronous_commit = off is set with ALTER SYSTEM (postgresql.auto.conf in the data dir).
+    # Memory for 62 GiB of RAM shared with other services (LOG.md 2026-10-16 (69)): the catalog's hot part in
+    # shared_buffers, the planner told the OS caches the rest; random_page_cost for the NVMe (the HDD tablespace
+    # pg_default keeps 4: ALTER TABLESPACE … SET (random_page_cost = 4)).
     command:
       - postgres
       - -c
       - shared_preload_libraries=pg_stat_statements
       - -c
-      - shared_buffers=${PG_SHARED_BUFFERS:-2GB}
+      - shared_buffers=${PG_SHARED_BUFFERS:-8GB}
+      - -c
+      - effective_cache_size=${PG_EFFECTIVE_CACHE_SIZE:-32GB}
+      - -c
+      - random_page_cost=1.1
+      - -c
+      - work_mem=16MB
+      - -c
+      - maintenance_work_mem=1GB
       - -c
       - max_wal_size=8GB
       - -c
       - checkpoint_timeout=15min
       - -c
       - wal_buffers=64MB
-    shm_size: 1g
+    # Parallel hash joins' shared memory: 1g failed with "could not resize shared memory segment" (LOG.md 2026-10-16 (61)).
+    shm_size: 2g
     stop_grace_period: 120s
     healthcheck:
       test: ['CMD-SHELL', 'pg_isready -U "$$POSTGRES_USER" -d "$$POSTGRES_DB"']