limit database creation concurrency to 1

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

.changeset/fresh-penguins-cry.md

@@ -0,0 +1,5 @@
+---
+'@backstage/backend-common': patch
+---
+
+Limit the database creation concurrency to one, defensively

packages/backend-common/package.json

@@ -96,6 +96,7 @@
     "minimatch": "^5.0.0",
     "mysql2": "^2.2.5",
     "node-fetch": "^2.6.7",
+    "p-limit": "^3.1.0",
     "pg": "^8.11.3",
     "raw-body": "^2.4.1",
     "tar": "^6.1.12",

packages/backend-common/src/database/connection.ts

@@ -18,6 +18,7 @@ import { Config } from '@backstage/config';
 import { JsonObject } from '@backstage/types';
 import { InputError } from '@backstage/errors';
 import knexFactory, { Knex } from 'knex';
+import limiterFactory from 'p-limit';
 import { mergeDatabaseConfig } from './config';
 import { DatabaseConnector } from './types';
 
@@ -35,6 +36,12 @@ type DatabaseClient =
   | 'mysql2'
   | string;
 
+// This limits the number of concurrent CREATE DATABASE and CREATE SCHEMA
+// commands, globally, to just one. This is overly defensive, and was added as
+// an attempt to counteract the pool issues on recent node versions. See
+// https://github.com/backstage/backstage/pull/19988
+const ddlLimiter = limiterFactory(1);
+
 /**
  * Mapping of client type to supported database connectors
  *
@@ -83,9 +90,8 @@ export async function ensureDatabaseExists(
 ): Promise<void> {
   const client: DatabaseClient = dbConfig.getString('client');
 
-  return ConnectorMapping[client]?.ensureDatabaseExists?.(
-    dbConfig,
-    ...databases,
+  return await ddlLimiter(() =>
+    ConnectorMapping[client]?.ensureDatabaseExists?.(dbConfig, ...databases),
   );
 }
 
@@ -100,9 +106,8 @@ export async function ensureSchemaExists(
 ): Promise<void> {
   const client: DatabaseClient = dbConfig.getString('client');
 
-  return await ConnectorMapping[client]?.ensureSchemaExists?.(
-    dbConfig,
-    ...schemas,
+  return await ddlLimiter(() =>
+    ConnectorMapping[client]?.ensureSchemaExists?.(dbConfig, ...schemas),
   );
 }
 

yarn.lock

@@ -3560,6 +3560,7 @@ __metadata:
     msw: ^1.0.0
     mysql2: ^2.2.5
     node-fetch: ^2.6.7
+    p-limit: ^3.1.0
     pg: ^8.11.3
     raw-body: ^2.4.1
     supertest: ^6.1.3