Скорректировал package.json в части команд запуска. Убрал еще одну лишнюю переменную с количеством pg соединений. Default value у pg pool = 10, чего должно хватать

.env.example

@@ -5,8 +5,5 @@ CORS_ALLOWED_ORIGINS=http://localhost:3000,http://localhost:5173
 # Optional. When set, POST /ingest requires x-api-key: <value>.
 INGEST_API_KEY=
 
-# Pool sizing for node-postgres.
-PG_POOL_MAX=20
-
 # Poll interval for GET /current/events SSE snapshots.
 CURRENT_EVENTS_POLL_MS=1000

.env.local.example

@@ -2,5 +2,4 @@ PORT=3101
 DATABASE_URL=postgres://greact:pG3526l4@194.36.208.86:5433/cloud
 CORS_ALLOWED_ORIGINS=http://localhost:3000,http://localhost:5173
 INGEST_API_KEY=
-PG_POOL_MAX=20
 CURRENT_EVENTS_POLL_MS=1000

docker-compose.yml

@@ -9,7 +9,6 @@ services:
       DATABASE_URL: ${DATABASE_URL}
       CORS_ALLOWED_ORIGINS: ${CORS_ALLOWED_ORIGINS}
       INGEST_API_KEY: ${INGEST_API_KEY}
-      PG_POOL_MAX: ${PG_POOL_MAX}
       CURRENT_EVENTS_POLL_MS: ${CURRENT_EVENTS_POLL_MS}
     ports:
       - "${PORT}:${PORT}"

package.json

@@ -6,8 +6,8 @@
   "license": "PERSONAL",
   "scripts": {
     "build": "nest build",
-    "start": "node --env-file=.env ./node_modules/@nestjs/cli/bin/nest.js start",
-    "start:dev": "node --env-file=.env ./node_modules/@nestjs/cli/bin/nest.js start --watch",
+    "start": "nest start --exec \"node --env-file=.env\"",
+    "start:dev": "nest start --watch --exec \"node --env-file=.env\"",
     "start:prod": "node dist/main.js",
     "lint": "eslint \"src/**/*.ts\"",
     "test": "jest --runInBand"

src/db/db.service.ts

@@ -15,7 +15,6 @@ export class DbService implements OnModuleInit, OnModuleDestroy {
   async onModuleInit(): Promise<void> {
     this.pool = new Pool({
       connectionString: process.env.DATABASE_URL,
-      max: Number(process.env.PG_POOL_MAX),
       idleTimeoutMillis: 30_000,
       connectionTimeoutMillis: 5_000,
       statement_timeout: 60_000,