fix: parallel workers postgres fix

Author: VladislavKudrin

README.md

@@ -167,6 +167,24 @@ docker compose logs -f index-service
 
 :information_source: _Index creation can take several hours but significantly speeds up queries for transactions by address and asset lookups. See [Index Service Documentation](./packages/index-service/README.md) for details on created indexes, customization, and best practices._
 
+### PostgreSQL 17 Configuration (Custom Deployments)
+
+If you are running a custom PostgreSQL 17 deployment (not using our docker-compose), add the following to your `postgresql.conf` to prevent query backlog under concurrent load:
+
+```
+max_parallel_workers_per_gather = 0
+```
+
+Or apply it at runtime:
+```sql
+ALTER SYSTEM SET max_parallel_workers_per_gather = 0;
+```
+```sql
+SELECT pg_reload_conf();
+```
+
+This is applied automatically when using our docker-compose stack.
+
 ### Check Cardano DB sync progress
 Use the GraphQL Playground in the browser at http://localhost:3100/graphql:
 > **_Note_** This Query is not available in early Era's of Cardano.

docker-compose.yml

@@ -10,7 +10,7 @@ services:
       - POSTGRES_USER_FILE=/run/secrets/postgres_user
     ports:
       - ${POSTGRES_PORT}:${POSTGRES_PORT}
-    command: -p ${POSTGRES_PORT}
+    command: -p ${POSTGRES_PORT} -c max_parallel_workers_per_gather=0
     secrets:
       - postgres_db
       - postgres_password