Add "FOR UPDATE" in the subqueries of PATCH & DELETE requests

src/odata-to-abstract-sql.ts

@@ -21,6 +21,7 @@
 	FromNode,
 	WhereNode,
 	OrderByNode,
+	LockingClauseNode,
 	LimitNode,
 	OffsetNode,
 	NumberTypeNodes,
@@ -231,7 +232,12 @@
 	public where: Array<WhereNode[1]> = [];
 	public joins: JoinTypeNodes[] = [];
 	public extras: Array<
-		FieldsNode | ValuesNode | OrderByNode | LimitNode | OffsetNode
+		| FieldsNode
+		| ValuesNode
+		| OrderByNode
+		| LimitNode
+		| OffsetNode
+		| LockingClauseNode
 	> = [];
 
 	merge(otherQuery: Query): void {
@@ -807,6 +813,48 @@
 			if (hasQueryOpts) {
 				this.AddQueryOptions(resource, path, subQuery);
 			}
+
+			let lockStrength: LockingClauseNode[1] = 'UPDATE';
+			if (
+				method === 'PATCH' &&
+				// That's always set for PATCHes, so we only check it to keep TS happy.
+				bindVars != null
+			) {
+				// The FOR UPDATE lock mode is also acquired by any DELETE on a row,
+				// and also by an UPDATE that modifies the values of certain columns.
+				// Currently, the set of columns considered for the UPDATE case are those
+				// that have a unique index on them that can be used in a foreign key
+				// (so partial indexes and expressional indexes are not considered).
+				// FOR NO KEY UPDATE ... is acquired by any UPDATE that does not acquire a FOR UPDATE lock.
+				// See: https://www.postgresql.org/docs/17/explicit-locking.html#LOCKING-ROWS
+				const fieldsPartOfUniqueIndexes = new Set([
+					...resource.fields
+						.filter(
+							(field) =>
+								field.index === 'UNIQUE' || field.index === 'PRIMARY KEY',
+						)
+						.map((field) => field.fieldName),
+					...resource.indexes
+						.filter(
+							(idx) =>
+								(idx.type === 'UNIQUE' && idx.predicate == null) ||
+								idx.type === 'PRIMARY KEY',
+						)
+						.flatMap((idx) => idx.fields),
+				]);
+				const updatesFieldPartOfUniqueIndex = bindVars.some((b) =>
+					fieldsPartOfUniqueIndexes.has(b[0]),
+				);
+				if (!updatesFieldPartOfUniqueIndex) {
+					lockStrength = 'NO KEY UPDATE';
+				}
+			}
+			subQuery.extras.push([
+				'LockingClause',
+				lockStrength,
+				[resource.tableAlias],
+			]);
+
 			query.where.push([
 				'In',
 				referencedIdField,

test/filterby.ts

@@ -15,6 +15,7 @@ let operandToAbstractSQLFactory = $operandToAbstractSQLFactory;
 
 import test from './test.js';
 import _ from 'lodash';
+import type { LockingClauseNode } from '@balena/abstract-sql-compiler';
 
 let operandToAbstractSQL: ReturnType<typeof operandToAbstractSQLFactory>;
 
@@ -559,7 +560,8 @@ run(function () {
 			)
 			.from('pilot');
 	};
-	const updateWhere = [
+
+	const getUpdateWhere = (lockStrength: LockingClauseNode[1]) => [
 		'In',
 		['ReferencedField', 'pilot', 'id'],
 		[
@@ -569,6 +571,7 @@ run(function () {
 			pilotPilotCanFlyPlaneLeftJoin,
 			pilotPilotCanFlyPlanePlaneLeftJoin,
 			['Where', abstractsql],
+			['LockingClause', lockStrength, ['pilot']],
 		],
 	];
 
@@ -605,7 +608,7 @@ run(function () {
 				.to.be.a.query.that.updates.fields('name')
 				.values(['Bind', ['pilot', 'name']])
 				.from('pilot')
-				.where(updateWhere);
+				.where(getUpdateWhere('NO KEY UPDATE'));
 		});
 	});
 
@@ -654,7 +657,7 @@ run(function () {
 						'Default',
 					)
 					.from('pilot')
-					.where(updateWhere);
+					.where(getUpdateWhere('UPDATE'));
 			});
 		});
 	});
@@ -706,6 +709,7 @@ run(function () {
 							],
 						],
 						['Where', abstractsql],
+						['LockingClause', 'UPDATE', ['pilot']],
 					],
 				]);
 		});
@@ -806,7 +810,14 @@ run([['Number', 1]], function () {
 			)
 			.from('pilot');
 	};
-	const updateWhere = [
+
+	test('/pilot(1)?$filter=' + odata, 'POST', { name }, (result) => {
+		it('should insert into pilot where "' + odata + '"', () => {
+			insertTest(result);
+		});
+	});
+
+	const getUpdateWhere = (lockStrength: LockingClauseNode[1]) => [
 		'And',
 		['IsNotDistinctFrom', ['ReferencedField', 'pilot', 'id'], ['Bind', 0]],
 		[
@@ -820,23 +831,18 @@ run([['Number', 1]], function () {
 				],
 				['From', ['Table', 'pilot']],
 				['Where', abstractsql],
+				['LockingClause', lockStrength, ['pilot']],
 			],
 		],
 	];
 
-	test('/pilot(1)?$filter=' + odata, 'POST', { name }, (result) => {
-		it('should insert into pilot where "' + odata + '"', () => {
-			insertTest(result);
-		});
-	});
-
 	test('/pilot(1)?$filter=' + odata, 'PATCH', { name }, (result) => {
 		it('should update the pilot with id 1', () => {
 			expect(result)
 				.to.be.a.query.that.updates.fields('name')
 				.values(['Bind', ['pilot', 'name']])
 				.from('pilot')
-				.where(updateWhere);
+				.where(getUpdateWhere('NO KEY UPDATE'));
 		});
 	});
 
@@ -879,7 +885,7 @@ run([['Number', 1]], function () {
 						'Default',
 					)
 					.from('pilot')
-					.where(updateWhere);
+					.where(getUpdateWhere('UPDATE'));
 			});
 		});
 	});
@@ -2139,6 +2145,7 @@ test(
 									['Bind', 0],
 								],
 							],
+							['LockingClause', 'NO KEY UPDATE', ['copilot']],
 						],
 					],
 				],
@@ -2198,6 +2205,7 @@ test(
 									['Bind', 0],
 								],
 							],
+							['LockingClause', 'UPDATE', ['copilot']],
 						],
 					],
 				],

test/paging.ts

@@ -49,6 +49,7 @@ test('/pilot?$top=5&$skip=100', 'PATCH', { name }, (result) => {
 					['From', ['Table', 'pilot']],
 					['Limit', ['Bind', 0]],
 					['Offset', ['Bind', 1]],
+					['LockingClause', 'NO KEY UPDATE', ['pilot']],
 				],
 			]);
 	});
@@ -69,6 +70,7 @@ test('/pilot?$top=5&$skip=100', 'DELETE', (result) => {
 					['From', ['Table', 'pilot']],
 					['Limit', ['Bind', 0]],
 					['Offset', ['Bind', 1]],
+					['LockingClause', 'UPDATE', ['pilot']],
 				],
 			]);
 	});