From ca33060e0bd30c6d077f8dd18ca8492d50c06a92 Mon Sep 17 00:00:00 2001
From: Charlie Kolb <charlie@n8n.io>
Date: Thu, 7 May 2026 17:00:04 +0200
Subject: [PATCH] fix(core): Advance Postgres IDENTITY sequences after entity
 import (#29762)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 .../services/__tests__/import.service.test.ts | 53 +++++++++++++++++++
 packages/cli/src/services/import.service.ts   | 49 +++++++++++++++++
 2 files changed, 102 insertions(+)

diff --git a/packages/cli/src/services/__tests__/import.service.test.ts b/packages/cli/src/services/__tests__/import.service.test.ts
index 962a6879089..852758bb9fc 100644
--- a/packages/cli/src/services/__tests__/import.service.test.ts
+++ b/packages/cli/src/services/__tests__/import.service.test.ts
@@ -1106,4 +1106,57 @@ describe('ImportService', () => {
 			expect(mockDataTableDDLService.dropTable).not.toHaveBeenCalled();
 		});
 	});
+
+	describe('advanceIdentitySequences', () => {
+		it('should run setval for each identity column on Postgres', async () => {
+			// @ts-expect-error overriding for the test
+			mockDataSource.options = { type: 'postgres' };
+
+			mockEntityManager.query = jest
+				.fn()
+				// information_schema lookup for "workflow_dependency"
+				.mockResolvedValueOnce([{ column_name: 'id' }])
+				// setval call returns nothing meaningful
+				.mockResolvedValueOnce(undefined)
+				// information_schema lookup for "insights_metadata" (has 'metaId')
+				.mockResolvedValueOnce([{ column_name: 'metaId' }])
+				.mockResolvedValueOnce(undefined)
+				// information_schema lookup for "user" (no identity columns)
+				.mockResolvedValueOnce([]);
+
+			await importService.advanceIdentitySequences(mockEntityManager, [
+				'workflow_dependency',
+				'insights_metadata',
+				'user',
+			]);
+
+			const setvalCalls = (mockEntityManager.query as jest.Mock).mock.calls.filter(
+				([sql]) => typeof sql === 'string' && sql.includes('setval('),
+			);
+			expect(setvalCalls).toHaveLength(2);
+			// Quoted table identifier passed through to pg_get_serial_sequence
+			// (regclass folds unquoted names to lowercase, so the quoted form is required).
+			expect(setvalCalls[0][1]).toEqual(['"workflow_dependency"', 'id']);
+			expect(setvalCalls[1][1]).toEqual(['"insights_metadata"', 'metaId']);
+		});
+
+		it('should be a no-op on SQLite', async () => {
+			// SQLite is the default in beforeEach.
+			mockEntityManager.query = jest.fn();
+
+			await importService.advanceIdentitySequences(mockEntityManager, ['workflow_dependency']);
+
+			expect(mockEntityManager.query).not.toHaveBeenCalled();
+		});
+
+		it('should be a no-op when no tables are provided', async () => {
+			// @ts-expect-error overriding for the test
+			mockDataSource.options = { type: 'postgres' };
+			mockEntityManager.query = jest.fn();
+
+			await importService.advanceIdentitySequences(mockEntityManager, []);
+
+			expect(mockEntityManager.query).not.toHaveBeenCalled();
+		});
+	});
 });
diff --git a/packages/cli/src/services/import.service.ts b/packages/cli/src/services/import.service.ts
index 3e9afd97378..379f60ca65b 100644
--- a/packages/cli/src/services/import.service.ts
+++ b/packages/cli/src/services/import.service.ts
@@ -500,6 +500,11 @@ export class ImportService {
 				customEncryptionKey,
 			);
 
+			// Postgres IDENTITY sequences don't auto-advance when explicit ids are
+			// inserted, so subsequent implicit inserts would collide. Reset each
+			// imported table's sequence to MAX(col).
+			await this.advanceIdentitySequences(transactionManager, tableNames);
+
 			// After the data_table / data_table_column registry rows are imported,
 			// recreate the dynamic backing tables (empty) so the imported tables work.
 			await this.recreateDataTableUserTablesFromRegistry(transactionManager);
@@ -768,6 +773,50 @@ export class ImportService {
 		this.logger.info(`✅ Recreated ${dataTables.length} data-table backing table(s)`);
 	}
 
+	/**
+	 * Advance Postgres IDENTITY sequences to MAX(col) for every identity column
+	 * in the given tables. No-op on SQLite, where INTEGER PRIMARY KEY auto-bumps
+	 * its rowid sequence on inserts with explicit ids.
+	 */
+	async advanceIdentitySequences(
+		transactionManager: EntityManager,
+		tableNames: string[],
+	): Promise<void> {
+		if (this.dataSource.options.type !== 'postgres') return;
+		if (tableNames.length === 0) return;
+
+		this.logger.info('\n🔢 Advancing Postgres IDENTITY sequences...');
+		let advanced = 0;
+
+		for (const tableName of tableNames) {
+			const identityColumns: Array<{ column_name: string }> = await transactionManager.query(
+				`SELECT column_name FROM information_schema.columns
+					WHERE table_schema = current_schema()
+						AND table_name = $1
+						AND identity_generation IS NOT NULL`,
+				[tableName],
+			);
+
+			if (identityColumns.length === 0) continue;
+
+			const escapedTable = this.dataSource.driver.escape(tableName);
+			for (const { column_name: columnName } of identityColumns) {
+				const escapedCol = this.dataSource.driver.escape(columnName);
+				await transactionManager.query(
+					`SELECT setval(
+						pg_get_serial_sequence($1, $2),
+						COALESCE((SELECT MAX(${escapedCol}) FROM ${escapedTable}), 1),
+						(SELECT MAX(${escapedCol}) FROM ${escapedTable}) IS NOT NULL
+					)`,
+					[escapedTable, columnName],
+				);
+				advanced++;
+			}
+		}
+
+		this.logger.info(`✅ Advanced ${advanced} sequence(s) across ${tableNames.length} table(s)`);
+	}
+
 	async disableForeignKeyConstraints(transactionManager: EntityManager) {
 		const disableCommand = this.foreignKeyCommands.disable[this.dataSource.options.type];