refactor(core): Improve DB directory setup (#3502)

packages/cli/src/databases/utils/migrationHelpers.ts

@@ -1,5 +1,7 @@
+/* eslint-disable no-await-in-loop */
 import { readFileSync, rmSync } from 'fs';
 import { UserSettings } from 'n8n-core';
+import { QueryRunner } from 'typeorm/query-runner/QueryRunner';
 import { getLogger } from '../../Logger';
 
 const PERSONALIZATION_SURVEY_FILENAME = 'personalizationSurvey.json';
@@ -53,3 +55,31 @@ export function logMigrationEnd(migrationName: string): void {
 		logger.warn('Migrations finished.');
 	}, 100);
 }
+
+export function chunkQuery(query: string, limit: number, offset = 0): string {
+	return `
+			${query}
+			LIMIT ${limit}
+			OFFSET ${offset}
+		`;
+}
+
+export async function runChunked(
+	queryRunner: QueryRunner,
+	query: string,
+	// eslint-disable-next-line @typescript-eslint/no-explicit-any
+	operation: (results: any[]) => Promise<void>,
+	limit = 100,
+): Promise<void> {
+	let offset = 0;
+	let chunkedQuery: string;
+	let chunkedQueryResults: unknown[];
+
+	do {
+		chunkedQuery = chunkQuery(query, limit, offset);
+		chunkedQueryResults = (await queryRunner.query(chunkedQuery)) as unknown[];
+		// pass a copy to prevent errors from mutation
+		await operation([...chunkedQueryResults]);
+		offset += limit;
+	} while (chunkedQueryResults.length === limit);
+}