diff --git a/src/zvec b/src/zvec
index bdf58fc..d9b0920 160000
--- a/src/zvec
+++ b/src/zvec
@@ -1 +1 @@
-Subproject commit bdf58fc2d2d2be3ee69eeb5fc62c4601d4d6cc6a
+Subproject commit d9b0920ac7426cad85a79e2daeb652e6698ae2bf
diff --git a/tests/data/operations.test.ts b/tests/data/operations.test.ts
index 288a3a8..c2ab116 100644
--- a/tests/data/operations.test.ts
+++ b/tests/data/operations.test.ts
@@ -4,7 +4,8 @@ import {
   ZVecCreateAndOpen,
   ZVecInitialize,
   ZVecLogLevel,
-  ZVecLogType
+  ZVecLogType,
+  isZVecError
 } from '../../src/index';
 import { batch, createTestSchema, expectDoc, makeDoc, verifyDocs } from './helpers';
 
@@ -116,19 +117,163 @@ describe('Data Operations Pipeline', () => {
       expect(collection.stats.indexCompleteness['sparse']).toBeCloseTo(1);
     });
 
-    // it('should resolve concurrent async queries with correct results', async () => {
-    //   const targets = [550, 600, 700, 800, 900, 950];
-    //   const queries = targets.map(k => {
-    //     const doc = makeDoc(k, 1, 1);
-    //     return collection.query({
-    //       fieldName: 'dense', vector: doc.vectors!.dense, topk: 10, includeVector: true,
-    //     }).then(results => ({ k, results }));
-    //   });
-
-    //   const allResults = await Promise.all(queries);
-    //   for (const { k, results } of allResults) {
-    //     expectDoc(results[0], k, 1, 1);
-    //   }
-    // });
+    it('should resolve concurrent async queries with correct results', async () => {
+      const targets = [550, 600, 700, 800, 900, 950];
+      const denseQueries = targets.map(k => {
+        const doc = makeDoc(k, 1, 1);
+        return collection.query({
+          fieldName: 'dense', vector: doc.vectors!.dense, topk: 10, includeVector: true,
+        }).then(results => ({ k, results }));
+      });
+      const sparseQueries = targets.map(k => {
+        const doc = makeDoc(k, 1, 1);
+        return collection.query({
+          fieldName: 'sparse', vector: doc.vectors!.sparse, topk: 10, includeVector: true,
+          filter: `title = "Product_${k}_v1"`
+        }).then(results => ({ k, results }));
+      });
+
+      const denseResults = await Promise.all(denseQueries);
+      for (const { k, results } of denseResults) {
+        expect(results.length).toBe(10);
+        expectDoc(results[0], k, 1, 1);
+      }
+      const sparseResults = await Promise.all(sparseQueries);
+      for (const { k, results } of sparseResults) {
+        expect(results.length).toBe(1);
+        expectDoc(results[0], k, 1, 1);
+      }
+    });
+  });
+
+
+  describe('update', () => {
+    it('should update scalar fields without changing vectors', () => {
+      batch(collection, 'update', 501, 1000, 3, 1);
+      verifyDocs(collection, 501, 1000, 3, 1);
+    });
+
+    it('should not affect docs outside the update range', () => {
+      verifyDocs(collection, 1, 500, 2, 2);
+      verifyDocs(collection, 1001, 1500, 2, 2);
+    });
+
+    it('should return correct results from vector query after field update', () => {
+      const doc = makeDoc(750, 3, 1);
+      const denseResults = collection.querySync({
+        fieldName: 'dense', vector: doc.vectors!.dense, topk: 1, includeVector: true
+      });
+      expectDoc(denseResults[0], 750, 3, 1);
+      const sparseResults = collection.querySync({
+        fieldName: 'sparse', vector: doc.vectors!.sparse, topk: 1, includeVector: true
+      });
+      expectDoc(sparseResults[0], 750, 3, 1);
+    });
+  });
+
+
+  describe('delete', () => {
+    it('should delete a single doc by id', () => {
+      const doc = makeDoc(1001, 2, 2);
+      const result = collection.deleteSync(doc.id);
+      expect(result.ok).toBe(true);
+      const fetched = collection.fetchSync(doc.id);
+      expect(fetched[doc.id]).toBeUndefined();
+    });
+
+    it('should delete a batch of docs by ids', () => {
+      const ids = Array.from({ length: 100 }, (_, i) => makeDoc(1002 + i, 2, 2).id);
+      const results = collection.deleteSync(ids);
+      for (const status of results) {
+        expect(status.ok).toBe(true);
+      }
+      const fetched = collection.fetchSync(ids);
+      for (const id of ids) {
+        expect(fetched[id]).toBeUndefined();
+      }
+    });
+
+    it('should reflect correct docCount after deletions', () => {
+      expect(collection.stats.docCount).toBe(1500 - 101);
+    });
+
+    it('should not affect remaining docs', () => {
+      verifyDocs(collection, 1, 500, 2, 2);
+      verifyDocs(collection, 501, 1000, 3, 1);
+      verifyDocs(collection, 1102, 1500, 2, 2);
+    });
+
+    it('should delete docs matching a filter expression', async () => {
+      const result = await collection.deleteByFilter('price > 2800 AND title LIKE "%_v2"');
+      expect(result.ok).toBe(true);
+      const fetched = collection.fetchSync(['doc_1400', 'doc_1450', 'doc_1500']);
+      expect(fetched['doc_1400']).toBeUndefined();
+      expect(fetched['doc_1450']).toBeUndefined();
+      expect(fetched['doc_1500']).toBeUndefined();
+    });
+
+    it('should not affect docs outside the filter criteria', () => {
+      verifyDocs(collection, 1, 500, 2, 2);
+      verifyDocs(collection, 501, 1000, 3, 1);
+      verifyDocs(collection, 1102, 1399, 2, 2);
+    });
+  });
+
+
+  describe('error handling', () => {
+    it('should throw on insert with missing required vector field', () => {
+      try {
+        collection.insertSync({ id: 'bad_1', fields: { title: 'no vectors' } } as any);
+        fail('expected to throw');
+      } catch (e) {
+        expect(isZVecError(e)).toBe(true);
+      }
+    });
+
+    it('should throw on insert with wrong vector dimension', () => {
+      try {
+        collection.insertSync({
+          id: 'bad_2',
+          vectors: { dense: [1, 2, 3], sparse: { 0: 1.0 } },
+          fields: { title: 'wrong dim' }
+        });
+        fail('expected to throw');
+      } catch (e) {
+        expect(isZVecError(e)).toBe(true);
+      }
+    });
+
+    it('should fail to insert a duplicate doc id', () => {
+      const doc = makeDoc(1, 1, 1);
+      const result = collection.insertSync(doc);
+      expect(result.ok).toBe(false);
+    });
+
+    it('should fail to update a non-existent doc', () => {
+      const result = collection.updateSync({ id: 'nonexistent', fields: { title: 'ghost' } });
+      expect(result.ok).toBe(false);
+    });
+
+    it('should throw on query with invalid filter syntax', () => {
+      const doc = makeDoc(1, 1, 1);
+      try {
+        collection.querySync({
+          fieldName: 'dense', vector: doc.vectors!.dense, topk: 1,
+          filter: 'invalid @@@ syntax'
+        });
+        fail('expected to throw');
+      } catch (e) {
+        expect(isZVecError(e)).toBe(true);
+      }
+    });
+
+    it('should throw on query with non-existent vector field', () => {
+      try {
+        collection.querySync({ fieldName: 'nonexistent', vector: [1, 2, 3], topk: 1 });
+        fail('expected to throw');
+      } catch (e) {
+        expect(isZVecError(e)).toBe(true);
+      }
+    });
   });
 });