From 149ad4d7b55b27265ac253ecb6a22d238bd4f341 Mon Sep 17 00:00:00 2001
From: kisk <tarekanwer23@yahoo.com>
Date: Tue, 27 Jan 2026 02:02:30 +0200
Subject: [PATCH 1/2] feat: forward structuralSharing to QueryObserver

---
 packages/query-db-collection/src/query.ts     | 10 ++++++-
 .../query-db-collection/tests/query.test.ts   | 26 +++++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/packages/query-db-collection/src/query.ts b/packages/query-db-collection/src/query.ts
index 6b3f83a90..ab47dc6a9 100644
--- a/packages/query-db-collection/src/query.ts
+++ b/packages/query-db-collection/src/query.ts
@@ -112,6 +112,13 @@ export interface QueryCollectionConfig<
     Array<T>,
     TQueryKey
   >[`staleTime`]
+  structuralSharing?: QueryObserverOptions<
+    Array<T>,
+    TError,
+    Array<T>,
+    Array<T>,
+    TQueryKey
+  >['structuralSharing']
 
   /**
    * Metadata to pass to the query.
@@ -543,6 +550,7 @@ export function queryCollectionOptions(
     onUpdate,
     onDelete,
     meta,
+    structuralSharing,
     ...baseCollectionConfig
   } = config
 
@@ -717,7 +725,6 @@ export function queryCollectionOptions(
         queryKey: key,
         queryFn: queryFunction,
         meta: extendedMeta,
-        structuralSharing: true,
         notifyOnChangeProps: `all`,
 
         // Only include options that are explicitly defined to allow QueryClient defaultOptions to be used
@@ -726,6 +733,7 @@ export function queryCollectionOptions(
         ...(retry !== undefined && { retry }),
         ...(retryDelay !== undefined && { retryDelay }),
         ...(staleTime !== undefined && { staleTime }),
+        ...(structuralSharing !== undefined && { structuralSharing }),
       }
 
       const localObserver = new QueryObserver<
diff --git a/packages/query-db-collection/tests/query.test.ts b/packages/query-db-collection/tests/query.test.ts
index 0a623de61..ffabe09ae 100644
--- a/packages/query-db-collection/tests/query.test.ts
+++ b/packages/query-db-collection/tests/query.test.ts
@@ -3500,6 +3500,32 @@ describe(`QueryCollection`, () => {
       // Clean up
       customQueryClient.clear()
     })
+
+    it(`should forward structuralSharing option to QueryObserver`, async () => {
+      const queryKey = [`structuralSharingTest`]
+      const queryFn = vi.fn().mockResolvedValue([])
+
+      const options = queryCollectionOptions({
+        id: `test`,
+        queryClient,
+        queryKey,
+        queryFn,
+        getKey,
+        structuralSharing: false,
+        startSync: true,
+      })
+
+      createCollection(options)
+
+      await vi.waitFor(() => {
+        expect(queryFn).toHaveBeenCalled()
+      })
+
+      const query = queryClient.getQueryCache().find({ queryKey })
+
+      expect(query).toBeDefined()
+      expect(query!.options.structuralSharing).toBe(false)
+    })
   })
 
   describe(`Query Garbage Collection`, () => {

From 7434ec1f565748a3b4c1b6d1b15e668fbf4e9039 Mon Sep 17 00:00:00 2001
From: kisk <tarekanwer23@yahoo.com>
Date: Tue, 27 Jan 2026 02:15:28 +0200
Subject: [PATCH 2/2] fix(query-db-collection): forward structuralSharing
 option

---
 .changeset/open-ideas-fix.md           | 5 +++++
 packages/db/src/query/builder/index.ts | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/open-ideas-fix.md

diff --git a/.changeset/open-ideas-fix.md b/.changeset/open-ideas-fix.md
new file mode 100644
index 000000000..a90008e0c
--- /dev/null
+++ b/.changeset/open-ideas-fix.md
@@ -0,0 +1,5 @@
+---
+'@tanstack/query-db-collection': patch
+---
+
+Forward structuralSharing option to QueryObserver
diff --git a/packages/db/src/query/builder/index.ts b/packages/db/src/query/builder/index.ts
index 6ef4d1ddc..fefc23d34 100644
--- a/packages/db/src/query/builder/index.ts
+++ b/packages/db/src/query/builder/index.ts
@@ -34,8 +34,8 @@ import type {
 import type {
   CompareOptions,
   Context,
-  GetResult,
   FunctionalHavingRow,
+  GetResult,
   GroupByCallback,
   JoinOnCallback,
   MergeContextForJoinCallback,