Tier 0 scalability: PgBouncer, Redis split, DB split, workers

T0.1: Separate redis-auth service (64mb, noeviction) for auth state
T0.2: Bump data Redis from 256mb to 1gb
T0.3: Per-app DATABASE_URL via PgBouncer to per-domain databases
T0.4: PgBouncer service (transaction mode, pool=20, max_conn=300);
      session.py pools reduced to 3+5 with timeout and recycle
T0.5: Hypercorn --workers 2 --keep-alive 75 on all 6 entrypoints

Deploy requires running split-databases.sh first to create per-domain
databases from the existing appdb.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -10,10 +10,8 @@ x-app-common: &app-common
     - /root/rose-ash/_config/app-config.yaml:/app/config/app-config.yaml:ro
 
 x-app-env: &app-env
-  DATABASE_URL: postgresql+asyncpg://postgres:change-me@db:5432/appdb
-  DATABASE_URL_ACCOUNT: postgresql+asyncpg://postgres:change-me@db:5432/appdb
-  DATABASE_URL_FEDERATION: postgresql+asyncpg://postgres:change-me@db:5432/appdb
-  ALEMBIC_DATABASE_URL: postgresql+psycopg://postgres:change-me@db:5432/appdb
+  DATABASE_URL_ACCOUNT: postgresql+asyncpg://postgres:change-me@pgbouncer:6432/db_account
+  DATABASE_URL_FEDERATION: postgresql+asyncpg://postgres:change-me@pgbouncer:6432/db_federation
   SMTP_HOST: ${SMTP_HOST}
   SMTP_PORT: ${SMTP_PORT}
   MAIL_FROM: ${MAIL_FROM}
@@ -25,7 +23,7 @@ x-app-env: &app-env
   GHOST_CONTENT_API_KEY: ${GHOST_CONTENT_API_KEY}
   GHOST_WEBHOOK_SECRET: ${GHOST_WEBHOOK_SECRET}
   GHOST_ADMIN_API_KEY: ${GHOST_ADMIN_API_KEY}
-  REDIS_AUTH_URL: redis://redis:6379/15
+  REDIS_AUTH_URL: redis://redis-auth:6379/0
   SECRET_KEY: ${SECRET_KEY}
   SUMUP_API_KEY: ${SUMUP_API_KEY}
   APP_URL_BLOG: https://blog.rose-ash.com
@@ -58,6 +56,8 @@ services:
       dockerfile: blog/Dockerfile
     environment:
       <<: *app-env
+      DATABASE_URL: postgresql+asyncpg://postgres:change-me@pgbouncer:6432/db_blog
+      ALEMBIC_DATABASE_URL: postgresql+psycopg://postgres:change-me@db:5432/db_blog
       REDIS_URL: redis://redis:6379/0
       DATABASE_HOST: db
       DATABASE_PORT: "5432"
@@ -74,6 +74,7 @@ services:
       - /root/rose-ash/_snapshot:/app/_snapshot
     environment:
       <<: *app-env
+      DATABASE_URL: postgresql+asyncpg://postgres:change-me@pgbouncer:6432/db_market
       REDIS_URL: redis://redis:6379/1
       DATABASE_HOST: db
       DATABASE_PORT: "5432"
@@ -86,6 +87,7 @@ services:
       dockerfile: cart/Dockerfile
     environment:
       <<: *app-env
+      DATABASE_URL: postgresql+asyncpg://postgres:change-me@pgbouncer:6432/db_cart
       REDIS_URL: redis://redis:6379/2
       DATABASE_HOST: db
       DATABASE_PORT: "5432"
@@ -98,6 +100,7 @@ services:
       dockerfile: events/Dockerfile
     environment:
       <<: *app-env
+      DATABASE_URL: postgresql+asyncpg://postgres:change-me@pgbouncer:6432/db_events
       REDIS_URL: redis://redis:6379/3
       DATABASE_HOST: db
       DATABASE_PORT: "5432"
@@ -110,6 +113,7 @@ services:
       dockerfile: federation/Dockerfile
     environment:
       <<: *app-env
+      DATABASE_URL: postgresql+asyncpg://postgres:change-me@pgbouncer:6432/db_federation
       REDIS_URL: redis://redis:6379/4
       DATABASE_HOST: db
       DATABASE_PORT: "5432"
@@ -122,6 +126,7 @@ services:
       dockerfile: account/Dockerfile
     environment:
       <<: *app-env
+      DATABASE_URL: postgresql+asyncpg://postgres:change-me@pgbouncer:6432/db_account
       REDIS_URL: redis://redis:6379/5
       DATABASE_HOST: db
       DATABASE_PORT: "5432"
@@ -145,6 +150,25 @@ services:
         constraints:
           - node.labels.gpu != true
 
+  pgbouncer:
+    image: bitnami/pgbouncer:latest
+    environment:
+      POSTGRESQL_HOST: db
+      POSTGRESQL_PORT: "5432"
+      POSTGRESQL_USERNAME: ${POSTGRES_USER:-postgres}
+      POSTGRESQL_PASSWORD: ${POSTGRES_PASSWORD:-change-me}
+      POSTGRESQL_DATABASE: "*"
+      PGBOUNCER_POOL_MODE: transaction
+      PGBOUNCER_DEFAULT_POOL_SIZE: "20"
+      PGBOUNCER_MAX_CLIENT_CONN: "300"
+      PGBOUNCER_MIN_POOL_SIZE: "5"
+    networks:
+      appnet:
+    deploy:
+      placement:
+        constraints:
+          - node.labels.gpu != true
+
   adminer:
     image: adminer
     networks:
@@ -164,16 +188,32 @@ services:
       appnet:
     command:
       redis-server
-      --maxmemory 256mb
+      --maxmemory 1gb
       --maxmemory-policy allkeys-lru
     deploy:
       placement:
         constraints:
           - node.labels.gpu != true
 
+  redis-auth:
+    image: redis:7-alpine
+    volumes:
+      - redis_auth_data:/data
+    networks:
+      appnet:
+    command:
+      redis-server
+      --maxmemory 64mb
+      --maxmemory-policy noeviction
+    deploy:
+      placement:
+        constraints:
+          - node.labels.gpu != true
+
 volumes:
   db_data_1:
   redis_data:
+  redis_auth_data:
 networks:
   appnet:
     driver: overlay