feat: improve grouping perf in edgeless (#14442)

fix #14433 

#### PR Dependency Tree


* **PR #14442** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
  * Level-of-detail thumbnails for large images.
  * Adaptive pacing for snapping, distribution and other alignment work.
  * RAF coalescer utility to batch high-frequency updates.
  * Operation timing utility to measure synchronous work.

* **Improvements**
* Batch group/ungroup reparenting that preserves element order and
selection.
  * Coalesced panning and drag updates to reduce jitter.
* Connector/group indexing for more reliable updates, deletions and
sync.
  * Throttled viewport refresh behavior.

* **Documentation**
  * Docs added for RAF coalescer and measureOperation.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/blocks/image/src/image-edgeless-block.ts

@@ -26,6 +26,11 @@ import {
 
 @Peekable()
 export class ImageEdgelessBlockComponent extends GfxBlockComponent<ImageBlockModel> {
+  private static readonly LOD_MIN_IMAGE_BYTES = 1024 * 1024;
+  private static readonly LOD_MIN_IMAGE_PIXELS = 1920 * 1080;
+  private static readonly LOD_MAX_ZOOM = 0.4;
+  private static readonly LOD_THUMBNAIL_MAX_EDGE = 256;
+
   static override styles = css`
     affine-edgeless-image {
       position: relative;
@@ -63,6 +68,11 @@ export class ImageEdgelessBlockComponent extends GfxBlockComponent<ImageBlockMod
       width: 100%;
       height: 100%;
     }
+
+    affine-edgeless-image .resizable-img {
+      position: relative;
+      overflow: hidden;
+    }
   `;
 
   resourceController = new ResourceController(
@@ -70,6 +80,12 @@ export class ImageEdgelessBlockComponent extends GfxBlockComponent<ImageBlockMod
     'Image'
   );
 
+  private _lodThumbnailUrl: string | null = null;
+  private _lodSourceUrl: string | null = null;
+  private _lodGeneratingSourceUrl: string | null = null;
+  private _lodGenerationToken = 0;
+  private _lastShouldUseLod = false;
+
   get blobUrl() {
     return this.resourceController.blobUrl$.value;
   }
@@ -96,6 +112,134 @@ export class ImageEdgelessBlockComponent extends GfxBlockComponent<ImageBlockMod
     });
   }
 
+  private _isLargeImage() {
+    const { width = 0, height = 0, size = 0 } = this.model.props;
+    const pixels = width * height;
+    return (
+      size >= ImageEdgelessBlockComponent.LOD_MIN_IMAGE_BYTES ||
+      pixels >= ImageEdgelessBlockComponent.LOD_MIN_IMAGE_PIXELS
+    );
+  }
+
+  private _shouldUseLod(blobUrl: string | null, zoom = this.gfx.viewport.zoom) {
+    return (
+      Boolean(blobUrl) &&
+      this._isLargeImage() &&
+      zoom <= ImageEdgelessBlockComponent.LOD_MAX_ZOOM
+    );
+  }
+
+  private _revokeLodThumbnail() {
+    if (!this._lodThumbnailUrl) {
+      return;
+    }
+
+    URL.revokeObjectURL(this._lodThumbnailUrl);
+    this._lodThumbnailUrl = null;
+  }
+
+  private _resetLodSource(blobUrl: string | null) {
+    if (this._lodSourceUrl === blobUrl) {
+      return;
+    }
+
+    this._lodGenerationToken += 1;
+    this._lodGeneratingSourceUrl = null;
+    this._lodSourceUrl = blobUrl;
+    this._revokeLodThumbnail();
+  }
+
+  private _createImageElement(src: string) {
+    return new Promise<HTMLImageElement>((resolve, reject) => {
+      const image = new Image();
+      image.decoding = 'async';
+      image.onload = () => resolve(image);
+      image.onerror = () => reject(new Error('Failed to load image'));
+      image.src = src;
+    });
+  }
+
+  private _createThumbnailBlob(image: HTMLImageElement) {
+    const maxEdge = ImageEdgelessBlockComponent.LOD_THUMBNAIL_MAX_EDGE;
+    const longestEdge = Math.max(image.naturalWidth, image.naturalHeight);
+    const scale = longestEdge > maxEdge ? maxEdge / longestEdge : 1;
+    const targetWidth = Math.max(1, Math.round(image.naturalWidth * scale));
+    const targetHeight = Math.max(1, Math.round(image.naturalHeight * scale));
+
+    const canvas = document.createElement('canvas');
+    canvas.width = targetWidth;
+    canvas.height = targetHeight;
+    const ctx = canvas.getContext('2d');
+    if (!ctx) {
+      return Promise.resolve<Blob | null>(null);
+    }
+    ctx.imageSmoothingEnabled = true;
+    ctx.imageSmoothingQuality = 'low';
+    ctx.drawImage(image, 0, 0, targetWidth, targetHeight);
+
+    return new Promise<Blob | null>(resolve => {
+      canvas.toBlob(resolve);
+    });
+  }
+
+  private _ensureLodThumbnail(blobUrl: string) {
+    if (
+      this._lodThumbnailUrl ||
+      this._lodGeneratingSourceUrl === blobUrl ||
+      !this._shouldUseLod(blobUrl)
+    ) {
+      return;
+    }
+
+    const token = ++this._lodGenerationToken;
+    this._lodGeneratingSourceUrl = blobUrl;
+
+    void this._createImageElement(blobUrl)
+      .then(image => this._createThumbnailBlob(image))
+      .then(blob => {
+        if (!blob || token !== this._lodGenerationToken || !this.isConnected) {
+          return;
+        }
+
+        const thumbnailUrl = URL.createObjectURL(blob);
+        if (token !== this._lodGenerationToken || !this.isConnected) {
+          URL.revokeObjectURL(thumbnailUrl);
+          return;
+        }
+
+        this._revokeLodThumbnail();
+        this._lodThumbnailUrl = thumbnailUrl;
+
+        if (this._shouldUseLod(this.blobUrl)) {
+          this.requestUpdate();
+        }
+      })
+      .catch(err => {
+        if (token !== this._lodGenerationToken || !this.isConnected) {
+          return;
+        }
+        console.error(err);
+      })
+      .finally(() => {
+        if (token === this._lodGenerationToken) {
+          this._lodGeneratingSourceUrl = null;
+        }
+      });
+  }
+
+  private _updateLodFromViewport(zoom: number) {
+    const shouldUseLod = this._shouldUseLod(this.blobUrl, zoom);
+    if (shouldUseLod === this._lastShouldUseLod) {
+      return;
+    }
+
+    this._lastShouldUseLod = shouldUseLod;
+    if (shouldUseLod && this.blobUrl) {
+      this._ensureLodThumbnail(this.blobUrl);
+    }
+    this.requestUpdate();
+  }
+
   override connectedCallback() {
     super.connectedCallback();
 
@@ -108,14 +252,32 @@ export class ImageEdgelessBlockComponent extends GfxBlockComponent<ImageBlockMod
 
     this.disposables.add(
       this.model.props.sourceId$.subscribe(() => {
+        this._resetLodSource(null);
         this.refreshData();
       })
     );
+
+    this.disposables.add(
+      this.gfx.viewport.viewportUpdated.subscribe(({ zoom }) => {
+        this._updateLodFromViewport(zoom);
+      })
+    );
+
+    this._lastShouldUseLod = this._shouldUseLod(this.blobUrl);
+  }
+
+  override disconnectedCallback() {
+    this._lodGenerationToken += 1;
+    this._lodGeneratingSourceUrl = null;
+    this._lodSourceUrl = null;
+    this._revokeLodThumbnail();
+    super.disconnectedCallback();
   }
 
   override renderGfxBlock() {
     const blobUrl = this.blobUrl;
     const { rotate = 0, size = 0, caption = 'Image' } = this.model.props;
+    this._resetLodSource(blobUrl);
 
     const containerStyleMap = styleMap({
       display: 'flex',
@@ -138,6 +300,13 @@ export class ImageEdgelessBlockComponent extends GfxBlockComponent<ImageBlockMod
     });
 
     const { loading, icon, description, error, needUpload } = resovledState;
+    const shouldUseLod = this._shouldUseLod(blobUrl);
+    if (shouldUseLod && blobUrl) {
+      this._ensureLodThumbnail(blobUrl);
+    }
+    this._lastShouldUseLod = shouldUseLod;
+    const imageUrl =
+      shouldUseLod && this._lodThumbnailUrl ? this._lodThumbnailUrl : blobUrl;
 
     return html`
       <div class="affine-image-container" style=${containerStyleMap}>
@@ -149,7 +318,7 @@ export class ImageEdgelessBlockComponent extends GfxBlockComponent<ImageBlockMod
                 class="drag-target"
                 draggable="false"
                 loading="lazy"
-                src=${blobUrl}
+                src=${imageUrl ?? ''}
                 alt=${caption}
                 @error=${this._handleError}
               />

blocksuite/affine/blocks/root/src/edgeless/configs/toolbar/misc.ts

@@ -33,7 +33,11 @@ import {
   ReleaseFromGroupIcon,
   UnlockIcon,
 } from '@blocksuite/icons/lit';
-import type { GfxModel } from '@blocksuite/std/gfx';
+import {
+  batchAddChildren,
+  batchRemoveChildren,
+  type GfxModel,
+} from '@blocksuite/std/gfx';
 import { html } from 'lit';
 
 import { renderAlignmentMenu } from './alignment';
@@ -61,14 +65,13 @@ export const builtinMiscToolbarConfig = {
 
         const group = firstModel.group;
 
-        // oxlint-disable-next-line unicorn/prefer-dom-node-remove
+        batchRemoveChildren(group, [firstModel]);
-        group.removeChild(firstModel);
 
         firstModel.index = ctx.gfx.layer.generateIndex();
 
         const parent = group.group;
         if (parent && parent instanceof GroupElementModel) {
-          parent.addChild(firstModel);
+          batchAddChildren(parent, [firstModel]);
         }
       },
     },
@@ -255,9 +258,12 @@ export const builtinMiscToolbarConfig = {
 
         // release other elements from their groups and group with top element
         otherElements.forEach(element => {
-          // oxlint-disable-next-line unicorn/prefer-dom-node-remove
+          if (element.group) {
-          element.group?.removeChild(element);
+            batchRemoveChildren(element.group, [element]);
-          topElement.group?.addChild(element);
+          }
+          if (topElement.group) {
+            batchAddChildren(topElement.group, [element]);
+          }
         });
 
         if (otherElements.length === 0) {

blocksuite/affine/blocks/surface/src/surface-model.ts

@@ -40,10 +40,146 @@ export const SurfaceBlockSchemaExtension =
 
 export class SurfaceBlockModel extends BaseSurfaceModel {
   private readonly _disposables: DisposableGroup = new DisposableGroup();
+  private readonly _connectorIdsByEndpoint = new Map<string, Set<string>>();
+  private readonly _connectorIndexDisposables = new DisposableGroup();
+  private readonly _connectorEndpoints = new Map<
+    string,
+    { sourceId: string | null; targetId: string | null }
+  >();
+
+  private _addConnectorEndpoint(endpointId: string, connectorId: string) {
+    const connectorIds = this._connectorIdsByEndpoint.get(endpointId);
+
+    if (connectorIds) {
+      connectorIds.add(connectorId);
+      return;
+    }
+
+    this._connectorIdsByEndpoint.set(endpointId, new Set([connectorId]));
+  }
+
+  private _isConnectorModel(model: unknown): model is ConnectorElementModel {
+    return (
+      !!model &&
+      typeof model === 'object' &&
+      'type' in model &&
+      (model as { type?: string }).type === 'connector'
+    );
+  }
+
+  private _removeConnectorEndpoint(endpointId: string, connectorId: string) {
+    const connectorIds = this._connectorIdsByEndpoint.get(endpointId);
+
+    if (!connectorIds) {
+      return;
+    }
+
+    connectorIds.delete(connectorId);
+
+    if (connectorIds.size === 0) {
+      this._connectorIdsByEndpoint.delete(endpointId);
+    }
+  }
+
+  private _removeConnectorFromIndex(connectorId: string) {
+    const endpoints = this._connectorEndpoints.get(connectorId);
+
+    if (!endpoints) {
+      return;
+    }
+
+    if (endpoints.sourceId) {
+      this._removeConnectorEndpoint(endpoints.sourceId, connectorId);
+    }
+
+    if (endpoints.targetId) {
+      this._removeConnectorEndpoint(endpoints.targetId, connectorId);
+    }
+
+    this._connectorEndpoints.delete(connectorId);
+  }
+
+  private _rebuildConnectorIndex() {
+    this._connectorIdsByEndpoint.clear();
+    this._connectorEndpoints.clear();
+
+    this.getElementsByType('connector').forEach(connector => {
+      this._setConnectorEndpoints(connector as ConnectorElementModel);
+    });
+  }
+
+  private _setConnectorEndpoints(connector: ConnectorElementModel) {
+    const sourceId = connector.source?.id ?? null;
+    const targetId = connector.target?.id ?? null;
+    const previousEndpoints = this._connectorEndpoints.get(connector.id);
+
+    if (
+      previousEndpoints?.sourceId === sourceId &&
+      previousEndpoints?.targetId === targetId
+    ) {
+      return;
+    }
+
+    if (previousEndpoints?.sourceId) {
+      this._removeConnectorEndpoint(previousEndpoints.sourceId, connector.id);
+    }
+
+    if (previousEndpoints?.targetId) {
+      this._removeConnectorEndpoint(previousEndpoints.targetId, connector.id);
+    }
+
+    if (sourceId) {
+      this._addConnectorEndpoint(sourceId, connector.id);
+    }
+
+    if (targetId) {
+      this._addConnectorEndpoint(targetId, connector.id);
+    }
+
+    this._connectorEndpoints.set(connector.id, {
+      sourceId,
+      targetId,
+    });
+  }
 
   override _init() {
     this._extendElement(elementsCtorMap);
     super._init();
+    this._rebuildConnectorIndex();
+    this._connectorIndexDisposables.add(
+      this.elementAdded.subscribe(({ id }) => {
+        const model = this.getElementById(id);
+
+        if (this._isConnectorModel(model)) {
+          this._setConnectorEndpoints(model);
+        }
+      })
+    );
+    this._connectorIndexDisposables.add(
+      this.elementUpdated.subscribe(({ id, props }) => {
+        if (!props['source'] && !props['target']) {
+          return;
+        }
+
+        const model = this.getElementById(id);
+
+        if (this._isConnectorModel(model)) {
+          this._setConnectorEndpoints(model);
+        }
+      })
+    );
+    this._connectorIndexDisposables.add(
+      this.elementRemoved.subscribe(({ id, type }) => {
+        if (type === 'connector') {
+          this._removeConnectorFromIndex(id);
+        }
+      })
+    );
+    this.deleted.subscribe(() => {
+      this._connectorIndexDisposables.dispose();
+      this._connectorIdsByEndpoint.clear();
+      this._connectorEndpoints.clear();
+    });
     this.store.provider
       .getAll(surfaceMiddlewareIdentifier)
       .forEach(({ middleware }) => {
@@ -52,13 +188,31 @@ export class SurfaceBlockModel extends BaseSurfaceModel {
   }
 
   getConnectors(id: string) {
-    const connectors = this.getElementsByType(
+    const connectorIds = this._connectorIdsByEndpoint.get(id);
-      'connector'
-    ) as unknown[] as ConnectorElementModel[];
 
-    return connectors.filter(
+    if (!connectorIds?.size) {
-      connector => connector.source?.id === id || connector.target?.id === id
+      return [];
-    );
+    }
+
+    const staleConnectorIds: string[] = [];
+    const connectors: ConnectorElementModel[] = [];
+
+    connectorIds.forEach(connectorId => {
+      const model = this.getElementById(connectorId);
+
+      if (!this._isConnectorModel(model)) {
+        staleConnectorIds.push(connectorId);
+        return;
+      }
+
+      connectors.push(model);
+    });
+
+    staleConnectorIds.forEach(connectorId => {
+      this._removeConnectorFromIndex(connectorId);
+    });
+
+    return connectors;
   }
 
   override getElementsByType<K extends keyof SurfaceElementModelMap>(

blocksuite/affine/gfx/connector/src/connector-watcher.ts

@@ -84,6 +84,8 @@ export const connectorWatcher: SurfaceMiddleware = (
     );
 
   return () => {
+    pendingFlag = false;
+    pendingList.clear();
     disposables.forEach(d => d.unsubscribe());
   };
 };

blocksuite/affine/gfx/group/package.json

@@ -26,6 +26,7 @@
     "@preact/signals-core": "^1.8.0",
     "@toeverything/theme": "^1.1.23",
     "@types/lodash-es": "^4.17.12",
+    "fractional-indexing": "^3.2.0",
     "lit": "^3.2.0",
     "lodash-es": "^4.17.23",
     "minimatch": "^10.1.1",
@@ -33,6 +34,9 @@
     "yjs": "^13.6.27",
     "zod": "^3.25.76"
   },
+  "devDependencies": {
+    "vitest": "^3.2.4"
+  },
   "exports": {
     ".": "./src/index.ts",
     "./view": "./src/view.ts",

blocksuite/affine/gfx/group/src/__tests__/group-api.unit.spec.ts

@@ -0,0 +1,152 @@
+import { beforeEach, describe, expect, test, vi } from 'vitest';
+
+vi.mock('fractional-indexing', () => ({
+  generateKeyBetween: vi.fn(),
+  generateNKeysBetween: vi.fn(),
+}));
+
+import { generateKeyBetween, generateNKeysBetween } from 'fractional-indexing';
+
+import { ungroupCommand } from '../command/group-api.js';
+
+type TestElement = {
+  id: string;
+  index: string;
+  group: TestElement | null;
+  childElements: TestElement[];
+  removeChildren?: (elements: TestElement[]) => void;
+  addChildren?: (elements: TestElement[]) => void;
+};
+
+const mockedGenerateNKeysBetween = vi.mocked(generateNKeysBetween);
+const mockedGenerateKeyBetween = vi.mocked(generateKeyBetween);
+
+const createElement = (
+  id: string,
+  index: string,
+  group: TestElement | null
+): TestElement => ({
+  id,
+  index,
+  group,
+  childElements: [],
+});
+
+const createUngroupFixture = () => {
+  const parent = createElement('parent', 'p0', null);
+  const left = createElement('left', 'a0', parent);
+  const right = createElement('right', 'a0', parent);
+  const group = createElement('group', 'm0', parent);
+  const childA = createElement('child-a', 'c0', group);
+  const childB = createElement('child-b', 'c1', group);
+
+  group.childElements = [childB, childA];
+  parent.childElements = [left, group, right];
+
+  parent.removeChildren = vi.fn();
+  parent.addChildren = vi.fn();
+  group.removeChildren = vi.fn();
+
+  const elementOrder = new Map<TestElement, number>([
+    [left, 0],
+    [group, 1],
+    [right, 2],
+    [childA, 3],
+    [childB, 4],
+  ]);
+
+  const selectionSet = vi.fn();
+  const gfx = {
+    layer: {
+      compare: (a: TestElement, b: TestElement) =>
+        (elementOrder.get(a) ?? 0) - (elementOrder.get(b) ?? 0),
+    },
+    selection: {
+      set: selectionSet,
+    },
+  };
+
+  const std = {
+    get: vi.fn(() => gfx),
+    store: {
+      transact: (callback: () => void) => callback(),
+    },
+  };
+
+  return {
+    childA,
+    childB,
+    group,
+    parent,
+    selectionSet,
+    std,
+  };
+};
+
+describe('ungroupCommand', () => {
+  beforeEach(() => {
+    mockedGenerateNKeysBetween.mockReset();
+    mockedGenerateKeyBetween.mockReset();
+  });
+
+  test('falls back to open-ended key generation when sibling interval is invalid', () => {
+    const fixture = createUngroupFixture();
+    mockedGenerateNKeysBetween
+      .mockImplementationOnce(() => {
+        throw new Error('interval reversed');
+      })
+      .mockReturnValueOnce(['n0', 'n1']);
+
+    const next = vi.fn();
+    ungroupCommand(
+      {
+        std: fixture.std,
+        group: fixture.group as any,
+      } as any,
+      next
+    );
+
+    expect(mockedGenerateNKeysBetween).toHaveBeenNthCalledWith(
+      1,
+      'a0',
+      'a0',
+      2
+    );
+    expect(mockedGenerateNKeysBetween).toHaveBeenNthCalledWith(
+      2,
+      'a0',
+      null,
+      2
+    );
+    expect(fixture.childA.index).toBe('n0');
+    expect(fixture.childB.index).toBe('n1');
+    expect(fixture.selectionSet).toHaveBeenCalledWith({
+      editing: false,
+      elements: ['child-a', 'child-b'],
+    });
+    expect(next).toHaveBeenCalledTimes(1);
+  });
+
+  test('falls back to key-by-key generation when all batched strategies fail', () => {
+    const fixture = createUngroupFixture();
+    mockedGenerateNKeysBetween.mockImplementation(() => {
+      throw new Error('invalid range');
+    });
+
+    let seq = 0;
+    mockedGenerateKeyBetween.mockImplementation(() => `k${seq++}`);
+
+    ungroupCommand(
+      {
+        std: fixture.std,
+        group: fixture.group as any,
+      } as any,
+      vi.fn()
+    );
+
+    expect(mockedGenerateNKeysBetween).toHaveBeenCalledTimes(4);
+    expect(mockedGenerateKeyBetween).toHaveBeenCalledTimes(2);
+    expect(fixture.childA.index).toBe('k0');
+    expect(fixture.childB.index).toBe('k1');
+  });
+});

blocksuite/affine/gfx/group/src/command/group-api.ts

@@ -4,7 +4,80 @@ import {
   MindmapElementModel,
 } from '@blocksuite/affine-model';
 import type { Command } from '@blocksuite/std';
-import { GfxControllerIdentifier, type GfxModel } from '@blocksuite/std/gfx';
+import {
+  batchAddChildren,
+  batchRemoveChildren,
+  type GfxController,
+  GfxControllerIdentifier,
+  type GfxModel,
+  measureOperation,
+} from '@blocksuite/std/gfx';
+import { generateKeyBetween, generateNKeysBetween } from 'fractional-indexing';
+
+const getTopLevelOrderedElements = (gfx: GfxController) => {
+  const topLevelElements = gfx.layer.layers.reduce<GfxModel[]>(
+    (elements, layer) => {
+      layer.elements.forEach(element => {
+        if (element.group === null) {
+          elements.push(element as GfxModel);
+        }
+      });
+
+      return elements;
+    },
+    []
+  );
+
+  topLevelElements.sort((a, b) => gfx.layer.compare(a, b));
+  return topLevelElements;
+};
+
+const buildUngroupIndexes = (
+  orderedElements: GfxModel[],
+  afterIndex: string | null,
+  beforeIndex: string | null,
+  fallbackAnchorIndex: string
+) => {
+  if (orderedElements.length === 0) {
+    return [];
+  }
+
+  const count = orderedElements.length;
+  const tryGenerateN = (left: string | null, right: string | null) => {
+    try {
+      const generated = generateNKeysBetween(left, right, count);
+      return generated.length === count ? generated : null;
+    } catch {
+      return null;
+    }
+  };
+
+  const tryGenerateOneByOne = (left: string | null, right: string | null) => {
+    try {
+      let cursor = left;
+      return orderedElements.map(() => {
+        cursor = generateKeyBetween(cursor, right);
+        return cursor;
+      });
+    } catch {
+      return null;
+    }
+  };
+
+  // Preferred: keep ungrouped children in the original group slot.
+  return (
+    tryGenerateN(afterIndex, beforeIndex) ??
+    // Fallback: ignore the upper bound when legacy/broken data has reversed interval.
+    tryGenerateN(afterIndex, null) ??
+    // Fallback: use group index as anchor when sibling interval is unavailable.
+    tryGenerateN(fallbackAnchorIndex, null) ??
+    // Last resort: always valid.
+    tryGenerateN(null, null) ??
+    // Defensive fallback for unexpected library behavior.
+    tryGenerateOneByOne(null, null) ??
+    []
+  );
+};
 
 export const createGroupCommand: Command<
   { elements: GfxModel[] | string[] },
@@ -39,6 +112,7 @@ export const createGroupFromSelectedCommand: Command<
   {},
   { groupId: string }
 > = (ctx, next) => {
+  measureOperation('edgeless:create-group-from-selected', () => {
     const { std } = ctx;
     const gfx = std.get(GfxControllerIdentifier);
     const { selection, surface } = gfx;
@@ -58,77 +132,98 @@ export const createGroupFromSelectedCommand: Command<
       return;
     }
 
-  const parent = selection.firstElement.group as GroupElementModel;
+    const parent = selection.firstElement.group;
-
+    let groupId: string | undefined;
-  if (parent !== null) {
+    std.store.transact(() => {
-    selection.selectedElements.forEach(element => {
-      // oxlint-disable-next-line unicorn/prefer-dom-node-remove
-      parent.removeChild(element);
-    });
-  }
-
       const [_, result] = std.command.exec(createGroupCommand, {
         elements: selection.selectedElements,
       });
+
       if (!result.groupId) {
         return;
       }
-  const group = surface.getElementById(result.groupId);
+
+      groupId = result.groupId;
+      const group = surface.getElementById(groupId);
 
       if (parent !== null && group) {
-    parent.addChild(group);
+        batchRemoveChildren(parent, selection.selectedElements);
+        batchAddChildren(parent, [group]);
+      }
+    });
+
+    if (!groupId) {
+      return;
     }
 
     selection.set({
       editing: false,
-    elements: [result.groupId],
+      elements: [groupId],
     });
 
-  next({ groupId: result.groupId });
+    next({ groupId });
+  });
 };
 
 export const ungroupCommand: Command<{ group: GroupElementModel }, {}> = (
   ctx,
   next
 ) => {
+  measureOperation('edgeless:ungroup', () => {
     const { std, group } = ctx;
     const gfx = std.get(GfxControllerIdentifier);
     const { selection } = gfx;
-  const parent = group.group as GroupElementModel;
+    const parent = group.group;
-  const elements = group.childElements;
+    const elements = [...group.childElements];
 
     if (group instanceof MindmapElementModel) {
       return;
     }
 
+    const orderedElements = [...elements].sort((a, b) =>
+      gfx.layer.compare(a, b)
+    );
+    const siblings = parent
+      ? [...parent.childElements].sort((a, b) => gfx.layer.compare(a, b))
+      : getTopLevelOrderedElements(gfx);
+    const groupPosition = siblings.indexOf(group);
+    const beforeSiblingIndex =
+      groupPosition > 0 ? (siblings[groupPosition - 1]?.index ?? null) : null;
+    const afterSiblingIndex =
+      groupPosition === -1
+        ? null
+        : (siblings[groupPosition + 1]?.index ?? null);
+    const nextIndexes = buildUngroupIndexes(
+      orderedElements,
+      beforeSiblingIndex,
+      afterSiblingIndex,
+      group.index
+    );
+
+    std.store.transact(() => {
       if (parent !== null) {
-    // oxlint-disable-next-line unicorn/prefer-dom-node-remove
+        batchRemoveChildren(parent, [group]);
-    parent.removeChild(group);
       }
 
-  elements.forEach(element => {
+      batchRemoveChildren(group, elements);
-    // oxlint-disable-next-line unicorn/prefer-dom-node-remove
-    group.removeChild(element);
-  });
 
       // keep relative index order of group children after ungroup
-  elements
+      orderedElements.forEach((element, idx) => {
-    .sort((a, b) => gfx.layer.compare(a, b))
+        const index = nextIndexes[idx];
-    .forEach(element => {
+        if (element.index !== index) {
-      std.store.transact(() => {
+          element.index = index;
-        element.index = gfx.layer.generateIndex();
+        }
-      });
       });
 
       if (parent !== null) {
-    elements.forEach(element => {
+        batchAddChildren(parent, orderedElements);
-      parent.addChild(element);
-    });
       }
+    });
 
     selection.set({
       editing: false,
-    elements: elements.map(ele => ele.id),
+      elements: orderedElements.map(ele => ele.id),
     });
     next();
+  });
 };

blocksuite/affine/gfx/group/vitest.config.ts

@@ -0,0 +1,25 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  esbuild: {
+    target: 'es2018',
+  },
+  test: {
+    globalSetup: '../../../scripts/vitest-global.js',
+    include: ['src/__tests__/**/*.unit.spec.ts'],
+    testTimeout: 1000,
+    coverage: {
+      provider: 'istanbul',
+      reporter: ['lcov'],
+      reportsDirectory: '../../../.coverage/affine-gfx-group',
+    },
+    onConsoleLog(log, type) {
+      if (log.includes('lit.dev/msg/dev-mode')) {
+        return false;
+      }
+      console.warn(`Unexpected ${type} log`, log);
+      throw new Error(log);
+    },
+    environment: 'happy-dom',
+  },
+});

blocksuite/affine/gfx/pointer/package.json

@@ -32,6 +32,9 @@
     "yjs": "^13.6.27",
     "zod": "^3.25.76"
   },
+  "devDependencies": {
+    "vitest": "^3.2.4"
+  },
   "exports": {
     ".": "./src/index.ts",
     "./view": "./src/view.ts"

blocksuite/affine/gfx/pointer/src/__tests__/adaptive-load-controller.unit.spec.ts

@@ -0,0 +1,73 @@
+import { describe, expect, test } from 'vitest';
+
+import {
+  AdaptiveCooldownController,
+  AdaptiveStrideController,
+} from '../snap/adaptive-load-controller.js';
+
+describe('AdaptiveStrideController', () => {
+  test('increases stride under heavy cost and respects maxStride', () => {
+    const controller = new AdaptiveStrideController({
+      heavyCostMs: 6,
+      maxStride: 3,
+      recoveryCostMs: 2,
+    });
+
+    controller.reportCost(10);
+    controller.reportCost(12);
+    controller.reportCost(15);
+
+    // stride should be capped at 3, so only every 3rd tick runs.
+    expect(controller.shouldSkip()).toBe(false);
+    expect(controller.shouldSkip()).toBe(true);
+    expect(controller.shouldSkip()).toBe(true);
+    expect(controller.shouldSkip()).toBe(false);
+  });
+
+  test('decreases stride when cost recovers and reset clears state', () => {
+    const controller = new AdaptiveStrideController({
+      heavyCostMs: 8,
+      maxStride: 4,
+      recoveryCostMs: 3,
+    });
+
+    controller.reportCost(12);
+    controller.reportCost(12);
+    controller.reportCost(1);
+
+    // From stride 3 recovered to stride 2: run every other tick.
+    expect(controller.shouldSkip()).toBe(false);
+    expect(controller.shouldSkip()).toBe(true);
+    expect(controller.shouldSkip()).toBe(false);
+
+    controller.reset();
+    expect(controller.shouldSkip()).toBe(false);
+    expect(controller.shouldSkip()).toBe(false);
+  });
+});
+
+describe('AdaptiveCooldownController', () => {
+  test('enters cooldown when cost exceeds threshold', () => {
+    const controller = new AdaptiveCooldownController({
+      cooldownFrames: 2,
+      maxCostMs: 5,
+    });
+
+    controller.reportCost(9);
+    expect(controller.shouldRun()).toBe(false);
+    expect(controller.shouldRun()).toBe(false);
+    expect(controller.shouldRun()).toBe(true);
+  });
+
+  test('reset exits cooldown immediately', () => {
+    const controller = new AdaptiveCooldownController({
+      cooldownFrames: 3,
+      maxCostMs: 5,
+    });
+
+    controller.reportCost(6);
+    expect(controller.shouldRun()).toBe(false);
+    controller.reset();
+    expect(controller.shouldRun()).toBe(true);
+  });
+});

blocksuite/affine/gfx/pointer/src/__tests__/pan-tool.unit.spec.ts

@@ -0,0 +1,177 @@
+import { EdgelessLegacySlotIdentifier } from '@blocksuite/affine-block-surface';
+import { MouseButton } from '@blocksuite/std/gfx';
+import { afterEach, describe, expect, test, vi } from 'vitest';
+
+import { PanTool } from '../tools/pan-tool.js';
+
+type PointerDownHandler = (event: {
+  raw: {
+    button: number;
+    preventDefault: () => void;
+  };
+}) => unknown;
+
+const mockRaf = () => {
+  let callback: FrameRequestCallback | undefined;
+  const requestAnimationFrameMock = vi
+    .fn()
+    .mockImplementation((cb: FrameRequestCallback) => {
+      callback = cb;
+      return 1;
+    });
+  const cancelAnimationFrameMock = vi.fn();
+
+  vi.stubGlobal('requestAnimationFrame', requestAnimationFrameMock);
+  vi.stubGlobal('cancelAnimationFrame', cancelAnimationFrameMock);
+
+  return {
+    getCallback: () => callback,
+    requestAnimationFrameMock,
+    cancelAnimationFrameMock,
+  };
+};
+
+const createToolFixture = (options?: {
+  currentToolName?: string;
+  currentToolOptions?: Record<string, unknown>;
+}) => {
+  const applyDeltaCenter = vi.fn();
+  const selectionSet = vi.fn();
+  const setTool = vi.fn();
+  const navigatorSettingUpdated = {
+    next: vi.fn(),
+  };
+  const currentToolName = options?.currentToolName;
+  const currentToolOption = {
+    toolType: currentToolName
+      ? ({
+          toolName: currentToolName,
+        } as any)
+      : undefined,
+    options: options?.currentToolOptions,
+  };
+
+  const gfx = {
+    viewport: {
+      zoom: 2,
+      applyDeltaCenter,
+    },
+    selection: {
+      surfaceSelections: [{ elements: ['shape-1'] }],
+      set: selectionSet,
+    },
+    tool: {
+      currentTool$: {
+        peek: () => null,
+      },
+      currentToolOption$: {
+        peek: () => currentToolOption,
+      },
+      setTool,
+    },
+    std: {
+      get: (identifier: unknown) => {
+        if (identifier === EdgelessLegacySlotIdentifier) {
+          return { navigatorSettingUpdated };
+        }
+        return null;
+      },
+    },
+    doc: {},
+  };
+
+  const tool = new PanTool(gfx as any);
+
+  return {
+    applyDeltaCenter,
+    navigatorSettingUpdated,
+    selectionSet,
+    setTool,
+    tool,
+  };
+};
+
+afterEach(() => {
+  vi.unstubAllGlobals();
+});
+
+describe('PanTool', () => {
+  test('flushes accumulated delta on dragEnd', () => {
+    mockRaf();
+    const { tool, applyDeltaCenter } = createToolFixture();
+
+    tool.dragStart({ x: 100, y: 100 } as any);
+    tool.dragMove({ x: 80, y: 60 } as any);
+    tool.dragMove({ x: 70, y: 40 } as any);
+
+    expect(applyDeltaCenter).not.toHaveBeenCalled();
+    tool.dragEnd({} as any);
+
+    expect(applyDeltaCenter).toHaveBeenCalledTimes(1);
+    expect(applyDeltaCenter).toHaveBeenCalledWith(15, 30);
+    expect(tool.panning$.value).toBe(false);
+  });
+
+  test('cancel in unmounted drops pending deltas', () => {
+    mockRaf();
+    const { tool, applyDeltaCenter } = createToolFixture();
+
+    tool.dragStart({ x: 100, y: 100 } as any);
+    tool.dragMove({ x: 80, y: 60 } as any);
+    tool.unmounted();
+    tool.dragEnd({} as any);
+
+    expect(applyDeltaCenter).not.toHaveBeenCalled();
+  });
+
+  test('middle click temporary pan restores frameNavigator with restoredAfterPan', () => {
+    const { tool, navigatorSettingUpdated, selectionSet, setTool } =
+      createToolFixture({
+        currentToolName: 'frameNavigator',
+        currentToolOptions: { mode: 'fit' },
+      });
+
+    const hooks: Partial<Record<'pointerDown', PointerDownHandler>> = {};
+    (tool as any).eventTarget = {
+      addHook: (eventName: 'pointerDown', handler: PointerDownHandler) => {
+        hooks[eventName] = handler;
+      },
+    };
+
+    tool.mounted();
+
+    const preventDefault = vi.fn();
+    const pointerDown = hooks.pointerDown!;
+    const ret = pointerDown({
+      raw: {
+        button: MouseButton.MIDDLE,
+        preventDefault,
+      },
+    });
+
+    expect(ret).toBe(false);
+    expect(preventDefault).toHaveBeenCalledTimes(1);
+    expect(navigatorSettingUpdated.next).toHaveBeenCalledWith({
+      blackBackground: false,
+    });
+    expect(setTool).toHaveBeenNthCalledWith(1, PanTool, {
+      panning: true,
+    });
+
+    document.dispatchEvent(
+      new PointerEvent('pointerup', { button: MouseButton.MIDDLE })
+    );
+
+    expect(selectionSet).toHaveBeenCalledWith([{ elements: ['shape-1'] }]);
+    expect(setTool).toHaveBeenNthCalledWith(
+      2,
+      expect.objectContaining({
+        toolName: 'frameNavigator',
+      }),
+      {
+        mode: 'fit',
+        restoredAfterPan: true,
+      }
+    );
+  });
+});

blocksuite/affine/gfx/pointer/src/snap/adaptive-load-controller.ts

@@ -0,0 +1,65 @@
+export class AdaptiveStrideController {
+  private _stride = 1;
+
+  private _ticks = 0;
+
+  constructor(
+    private readonly _options: {
+      heavyCostMs: number;
+      maxStride: number;
+      recoveryCostMs: number;
+    }
+  ) {}
+
+  reportCost(costMs: number) {
+    if (costMs > this._options.heavyCostMs) {
+      this._stride = Math.min(this._options.maxStride, this._stride + 1);
+      return;
+    }
+
+    if (costMs < this._options.recoveryCostMs && this._stride > 1) {
+      this._stride -= 1;
+    }
+  }
+
+  reset() {
+    this._stride = 1;
+    this._ticks = 0;
+  }
+
+  shouldSkip() {
+    const shouldSkip = this._stride > 1 && this._ticks % this._stride !== 0;
+    this._ticks += 1;
+    return shouldSkip;
+  }
+}
+
+export class AdaptiveCooldownController {
+  private _remainingFrames = 0;
+
+  constructor(
+    private readonly _options: {
+      cooldownFrames: number;
+      maxCostMs: number;
+    }
+  ) {}
+
+  reportCost(costMs: number) {
+    if (costMs > this._options.maxCostMs) {
+      this._remainingFrames = this._options.cooldownFrames;
+    }
+  }
+
+  reset() {
+    this._remainingFrames = 0;
+  }
+
+  shouldRun() {
+    if (this._remainingFrames <= 0) {
+      return true;
+    }
+
+    this._remainingFrames -= 1;
+    return false;
+  }
+}

blocksuite/affine/gfx/pointer/src/snap/snap-manager.ts

@@ -8,11 +8,18 @@ import {
   InteractivityExtension,
 } from '@blocksuite/std/gfx';
 
+import { AdaptiveStrideController } from './adaptive-load-controller';
 import type { SnapOverlay } from './snap-overlay';
 
 export class SnapExtension extends InteractivityExtension {
   static override key = 'snap-manager';
 
+  private static readonly MAX_ALIGN_SKIP_STRIDE = 3;
+
+  private static readonly ALIGN_HEAVY_COST_MS = 5;
+
+  private static readonly ALIGN_RECOVERY_COST_MS = 2;
+
   get snapOverlay() {
     return this.std.getOptional(
       OverlayIdentifier('snap-manager')
@@ -29,6 +36,11 @@ export class SnapExtension extends InteractivityExtension {
         }
 
         let alignBound: Bound | null = null;
+        const alignStride = new AdaptiveStrideController({
+          heavyCostMs: SnapExtension.ALIGN_HEAVY_COST_MS,
+          maxStride: SnapExtension.MAX_ALIGN_SKIP_STRIDE,
+          recoveryCostMs: SnapExtension.ALIGN_RECOVERY_COST_MS,
+        });
 
         return {
           onDragStart() {
@@ -42,6 +54,7 @@ export class SnapExtension extends InteractivityExtension {
                 return pre;
               }, [] as GfxModel[])
             );
+            alignStride.reset();
           },
           onDragMove(context: ExtensionDragMoveContext) {
             if (
@@ -53,14 +66,22 @@ export class SnapExtension extends InteractivityExtension {
               return;
             }
 
+            if (alignStride.shouldSkip()) {
+              return;
+            }
+
             const currentBound = alignBound.moveDelta(context.dx, context.dy);
+            const alignStart = performance.now();
             const alignRst = snapOverlay.align(currentBound);
+            const alignCost = performance.now() - alignStart;
+            alignStride.reportCost(alignCost);
 
             context.dx = alignRst.dx + context.dx;
             context.dy = alignRst.dy + context.dy;
           },
           clear() {
             alignBound = null;
+            alignStride.reset();
             snapOverlay.clear();
           },
         };

blocksuite/affine/gfx/pointer/src/snap/snap-overlay.ts

@@ -6,6 +6,8 @@ import {
 import { almostEqual, Bound, type IVec, Point } from '@blocksuite/global/gfx';
 import type { GfxModel } from '@blocksuite/std/gfx';
 
+import { AdaptiveCooldownController } from './adaptive-load-controller';
+
 interface Distance {
   horiz?: {
     /**
@@ -35,6 +37,9 @@ interface Distance {
 const ALIGN_THRESHOLD = 8;
 const DISTRIBUTION_LINE_OFFSET = 1;
 const STROKE_WIDTH = 2;
+const DISTRIBUTE_ALIGN_MAX_CANDIDATES = 160;
+const DISTRIBUTE_ALIGN_MAX_COST_MS = 5;
+const DISTRIBUTE_ALIGN_COOLDOWN_FRAMES = 2;
 
 export class SnapOverlay extends Overlay {
   static override overlayName: string = 'snap-manager';
@@ -75,6 +80,11 @@ export class SnapOverlay extends Overlay {
     vertical: [],
   };
 
+  private readonly _distributeCooldown = new AdaptiveCooldownController({
+    cooldownFrames: DISTRIBUTE_ALIGN_COOLDOWN_FRAMES,
+    maxCostMs: DISTRIBUTE_ALIGN_MAX_COST_MS,
+  });
+
   override clear() {
     this._referenceBounds = {
       vertical: [],
@@ -87,6 +97,7 @@ export class SnapOverlay extends Overlay {
     };
     this._distributedAlignLines = [];
     this._skippedElements.clear();
+    this._distributeCooldown.reset();
 
     super.clear();
   }
@@ -673,6 +684,13 @@ export class SnapOverlay extends Overlay {
       }
     }
 
+    const shouldTryDistribute =
+      this._referenceBounds.all.length <= DISTRIBUTE_ALIGN_MAX_CANDIDATES &&
+      this._distributeCooldown.shouldRun();
+
+    if (shouldTryDistribute) {
+      const distributeStart = performance.now();
+
       // point align priority is higher than distribute align
       if (rst.dx === 0) {
         this._alignDistributeHorizontally(rst, bound, threshold, viewport);
@@ -682,6 +700,10 @@ export class SnapOverlay extends Overlay {
         this._alignDistributeVertically(rst, bound, threshold, viewport);
       }
 
+      const distributeCost = performance.now() - distributeStart;
+      this._distributeCooldown.reportCost(distributeCost);
+    }
+
     this._renderer?.refresh();
 
     return rst;
@@ -776,24 +798,26 @@ export class SnapOverlay extends Overlay {
     });
     const verticalBounds: Bound[] = [];
     const horizBounds: Bound[] = [];
-    const allBounds: Bound[] = [];
+    const allCandidateElements = new Set<GfxModel>();
 
     vertCandidates.forEach(candidate => {
       if (skipped.has(candidate) || this._isSkippedElement(candidate)) return;
-      verticalBounds.push(candidate.elementBound);
+      const bound = candidate.elementBound;
-      allBounds.push(candidate.elementBound);
+      verticalBounds.push(bound);
+      allCandidateElements.add(candidate);
     });
 
     horizCandidates.forEach(candidate => {
       if (skipped.has(candidate) || this._isSkippedElement(candidate)) return;
-      horizBounds.push(candidate.elementBound);
+      const bound = candidate.elementBound;
-      allBounds.push(candidate.elementBound);
+      horizBounds.push(bound);
+      allCandidateElements.add(candidate);
     });
 
     this._referenceBounds = {
       horizontal: horizBounds,
       vertical: verticalBounds,
-      all: allBounds,
+      all: [...allCandidateElements].map(element => element.elementBound),
     };
   }
 

blocksuite/affine/gfx/pointer/src/tools/pan-tool.ts

@@ -4,7 +4,12 @@ import {
 } from '@blocksuite/affine-block-surface';
 import { on } from '@blocksuite/affine-shared/utils';
 import type { PointerEventState } from '@blocksuite/std';
-import { BaseTool, MouseButton, type ToolOptions } from '@blocksuite/std/gfx';
+import {
+  BaseTool,
+  createRafCoalescer,
+  MouseButton,
+  type ToolOptions,
+} from '@blocksuite/std/gfx';
 import { Signal } from '@preact/signals-core';
 
 interface RestorablePresentToolOptions {
@@ -21,13 +26,30 @@ export class PanTool extends BaseTool<PanToolOption> {
 
   private _lastPoint: [number, number] | null = null;
 
+  private _pendingDelta: [number, number] = [0, 0];
+
+  private readonly _deltaFlushCoalescer = createRafCoalescer<void>(() => {
+    this._flushPendingDelta();
+  });
+
   readonly panning$ = new Signal<boolean>(false);
 
+  private _flushPendingDelta() {
+    if (this._pendingDelta[0] === 0 && this._pendingDelta[1] === 0) {
+      return;
+    }
+
+    const [deltaX, deltaY] = this._pendingDelta;
+    this._pendingDelta = [0, 0];
+    this.gfx.viewport.applyDeltaCenter(deltaX, deltaY);
+  }
+
   override get allowDragWithRightButton(): boolean {
     return true;
   }
 
   override dragEnd(_: PointerEventState): void {
+    this._deltaFlushCoalescer.flush();
     this._lastPoint = null;
     this.panning$.value = false;
   }
@@ -43,12 +65,14 @@ export class PanTool extends BaseTool<PanToolOption> {
     const deltaY = lastY - e.y;
 
     this._lastPoint = [e.x, e.y];
-
+    this._pendingDelta[0] += deltaX / zoom;
-    viewport.applyDeltaCenter(deltaX / zoom, deltaY / zoom);
+    this._pendingDelta[1] += deltaY / zoom;
+    this._deltaFlushCoalescer.schedule(undefined);
   }
 
   override dragStart(e: PointerEventState): void {
     this._lastPoint = [e.x, e.y];
+    this._pendingDelta = [0, 0];
     this.panning$.value = true;
   }
 
@@ -120,4 +144,8 @@ export class PanTool extends BaseTool<PanToolOption> {
       return false;
     });
   }
+
+  override unmounted(): void {
+    this._deltaFlushCoalescer.cancel();
+  }
 }

blocksuite/affine/gfx/pointer/vitest.config.ts

@@ -0,0 +1,25 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  esbuild: {
+    target: 'es2018',
+  },
+  test: {
+    globalSetup: '../../../scripts/vitest-global.js',
+    include: ['src/__tests__/**/*.unit.spec.ts'],
+    testTimeout: 1000,
+    coverage: {
+      provider: 'istanbul',
+      reporter: ['lcov'],
+      reportsDirectory: '../../../.coverage/affine-gfx-pointer',
+    },
+    onConsoleLog(log, type) {
+      if (log.includes('lit.dev/msg/dev-mode')) {
+        return false;
+      }
+      console.warn(`Unexpected ${type} log`, log);
+      throw new Error(log);
+    },
+    environment: 'happy-dom',
+  },
+});

blocksuite/affine/model/src/blocks/frame/frame-model.ts

@@ -155,9 +155,22 @@ export class FrameBlockModel
   }
 
   removeChild(element: GfxModel): void {
+    this.removeChildren([element]);
+  }
+
+  removeChildren(elements: GfxModel[]): void {
+    const childIds = [...new Set(elements.map(element => element.id))];
+    if (!this.props.childElementIds || childIds.length === 0) {
+      return;
+    }
+
     this.store.transact(() => {
-      this.props.childElementIds &&
+      const childElementIds = this.props.childElementIds;
-        delete this.props.childElementIds[element.id];
+      if (!childElementIds) return;
+
+      childIds.forEach(childId => {
+        delete childElementIds[childId];
+      });
     });
   }
 }

blocksuite/affine/model/src/elements/group/group.ts

@@ -54,13 +54,22 @@ export class GroupElementModel extends GfxGroupLikeElementModel<GroupElementProp
   }
 
   override addChild(element: GfxModel) {
-    if (!canSafeAddToContainer(this, element)) {
+    this.addChildren([element]);
+  }
+
+  addChildren(elements: GfxModel[]) {
+    elements = [...new Set(elements)].filter(element =>
+      canSafeAddToContainer(this, element)
+    );
+    if (elements.length === 0) {
       return;
     }
 
     this.surface.store.transact(() => {
+      elements.forEach(element => {
         this.children.set(element.id, true);
       });
+    });
   }
 
   override containsBound(bound: Bound): boolean {
@@ -76,11 +85,22 @@ export class GroupElementModel extends GfxGroupLikeElementModel<GroupElementProp
   }
 
   removeChild(element: GfxModel) {
+    this.removeChildren([element]);
+  }
+
+  removeChildren(elements: GfxModel[]) {
     if (!this.children) {
       return;
     }
+    const childIds = [...new Set(elements.map(element => element.id))];
+    if (childIds.length === 0) {
+      return;
+    }
+
     this.surface.store.transact(() => {
-      this.children.delete(element.id);
+      childIds.forEach(childId => {
+        this.children.delete(childId);
+      });
     });
   }
 

blocksuite/docs/api/@blocksuite/std/gfx/README.md

@@ -34,6 +34,7 @@
 - [canSafeAddToContainer](functions/canSafeAddToContainer.md)
 - [compareLayer](functions/compareLayer.md)
 - [convert](functions/convert.md)
+- [createRafCoalescer](functions/createRafCoalescer.md)
 - [derive](functions/derive.md)
 - [generateKeyBetween](functions/generateKeyBetween.md)
 - [generateKeyBetweenV2](functions/generateKeyBetweenV2.md)
@@ -42,5 +43,6 @@
 - [GfxCompatible](functions/GfxCompatible.md)
 - [isGfxGroupCompatibleModel](functions/isGfxGroupCompatibleModel.md)
 - [local](functions/local.md)
+- [measureOperation](functions/measureOperation.md)
 - [observe](functions/observe.md)
 - [watch](functions/watch.md)

blocksuite/docs/api/@blocksuite/std/gfx/functions/createRafCoalescer.md

@@ -0,0 +1,27 @@
+[**BlockSuite API Documentation**](../../../../README.md)
+
+***
+
+[BlockSuite API Documentation](../../../../README.md) / [@blocksuite/std](../../README.md) / [gfx](../README.md) / createRafCoalescer
+
+# Function: createRafCoalescer()
+
+> **createRafCoalescer**\<`T`\>(`apply`): `RafCoalescer`\<`T`\>
+
+Coalesce high-frequency updates and only process the latest payload in one frame.
+
+## Type Parameters
+
+### T
+
+`T`
+
+## Parameters
+
+### apply
+
+(`payload`) => `void`
+
+## Returns
+
+`RafCoalescer`\<`T`\>

blocksuite/docs/api/@blocksuite/std/gfx/functions/measureOperation.md

@@ -0,0 +1,34 @@
+[**BlockSuite API Documentation**](../../../../README.md)
+
+***
+
+[BlockSuite API Documentation](../../../../README.md) / [@blocksuite/std](../../README.md) / [gfx](../README.md) / measureOperation
+
+# Function: measureOperation()
+
+> **measureOperation**\<`T`\>(`name`, `fn`): `T`
+
+Measure operation cost via Performance API when available.
+
+Marks are always cleared, while measure entries are intentionally retained
+so callers can inspect them from Performance tools.
+
+## Type Parameters
+
+### T
+
+`T`
+
+## Parameters
+
+### name
+
+`string`
+
+### fn
+
+() => `T`
+
+## Returns
+
+`T`

blocksuite/framework/std/src/__tests__/gfx/surface.unit.spec.ts

@@ -356,3 +356,63 @@ describe('convert decorator', () => {
     expect(elementModel.shapeType).toBe('rect');
   });
 });
+
+describe('surface group index cache', () => {
+  test('syncGroupChildrenIndex should replace outdated parent mappings', () => {
+    const { surfaceModel } = commonSetup();
+    const model = surfaceModel as any;
+
+    model._syncGroupChildrenIndex('group-1', ['a', 'b'], []);
+    expect(model._parentGroupMap.get('a')).toBe('group-1');
+    expect(model._parentGroupMap.get('b')).toBe('group-1');
+
+    model._syncGroupChildrenIndex('group-1', ['b', 'c']);
+    expect(model._parentGroupMap.has('a')).toBe(false);
+    expect(model._parentGroupMap.get('b')).toBe('group-1');
+    expect(model._parentGroupMap.get('c')).toBe('group-1');
+  });
+
+  test('removeGroupFromChildrenIndex should clear both child snapshot and reverse lookup', () => {
+    const { surfaceModel } = commonSetup();
+    const model = surfaceModel as any;
+
+    model._syncGroupChildrenIndex('group-2', ['x', 'y'], []);
+    model._removeGroupFromChildrenIndex('group-2');
+
+    expect(model._groupChildIdsMap.has('group-2')).toBe(false);
+    expect(model._parentGroupMap.has('x')).toBe(false);
+    expect(model._parentGroupMap.has('y')).toBe(false);
+  });
+
+  test('getGroup should recover from stale cache and update reverse lookup', () => {
+    const { surfaceModel } = commonSetup();
+    const model = surfaceModel as any;
+
+    const shapeId = surfaceModel.addElement({
+      type: 'testShape',
+    });
+    const shape = surfaceModel.getElementById(shapeId)!;
+
+    const fakeGroup = {
+      id: 'group-fallback',
+      hasChild: (element: { id: string }) => element.id === shapeId,
+    };
+
+    model._groupLikeModels.set(fakeGroup.id, fakeGroup);
+    model._parentGroupMap.set(shapeId, 'stale-group-id');
+
+    expect(surfaceModel.getGroup(shapeId)).toBe(fakeGroup);
+    expect(model._parentGroupMap.get(shapeId)).toBe(fakeGroup.id);
+    expect(model._parentGroupMap.has('stale-group-id')).toBe(false);
+
+    const otherShapeId = surfaceModel.addElement({
+      type: 'testShape',
+    });
+    model._parentGroupMap.set(otherShapeId, 'another-missing-group');
+    expect(surfaceModel.getGroup(otherShapeId)).toBeNull();
+    expect(model._parentGroupMap.has(otherShapeId)).toBe(false);
+
+    // keep one explicit check on element-based lookup path
+    expect(surfaceModel.getGroup(shape as any)).toBe(fakeGroup);
+  });
+});

blocksuite/framework/std/src/__tests__/gfx/tree.unit.spec.ts

@@ -0,0 +1,165 @@
+import { describe, expect, test, vi } from 'vitest';
+
+import {
+  type GfxGroupCompatibleInterface,
+  gfxGroupCompatibleSymbol,
+} from '../../gfx/model/base.js';
+import type { GfxModel } from '../../gfx/model/model.js';
+import {
+  batchAddChildren,
+  batchRemoveChildren,
+  canSafeAddToContainer,
+  descendantElementsImpl,
+  getTopElements,
+} from '../../utils/tree.js';
+
+type TestElement = {
+  id: string;
+  group: TestGroup | null;
+  groups: TestGroup[];
+};
+
+type TestGroup = TestElement & {
+  [gfxGroupCompatibleSymbol]: true;
+  childIds: string[];
+  childElements: GfxModel[];
+  addChild: (element: GfxModel) => void;
+  removeChild: (element: GfxModel) => void;
+  hasChild: (element: GfxModel) => boolean;
+  hasDescendant: (element: GfxModel) => boolean;
+};
+
+const createElement = (id: string): TestElement => ({
+  id,
+  group: null,
+  groups: [],
+});
+
+const createGroup = (id: string): TestGroup => {
+  const group: TestGroup = {
+    id,
+    [gfxGroupCompatibleSymbol]: true,
+    group: null,
+    groups: [],
+    childIds: [],
+    childElements: [],
+    addChild(element: GfxModel) {
+      const child = element as unknown as TestElement;
+      if (this.childElements.includes(element)) {
+        return;
+      }
+      this.childElements.push(element);
+      this.childIds.push(child.id);
+      child.group = this;
+      child.groups = [...this.groups, this];
+    },
+    removeChild(element: GfxModel) {
+      const child = element as unknown as TestElement;
+      this.childElements = this.childElements.filter(item => item !== element);
+      this.childIds = this.childIds.filter(id => id !== child.id);
+      if (child.group === this) {
+        child.group = null;
+        child.groups = [];
+      }
+    },
+    hasChild(element: GfxModel) {
+      return this.childElements.includes(element);
+    },
+    hasDescendant(element: GfxModel) {
+      return descendantElementsImpl(
+        this as unknown as GfxGroupCompatibleInterface
+      ).includes(element);
+    },
+  };
+
+  return group;
+};
+
+describe('tree utils', () => {
+  test('batchAddChildren prefers container.addChildren and deduplicates', () => {
+    const a = createElement('a') as unknown as GfxModel;
+    const b = createElement('b') as unknown as GfxModel;
+    const container = {
+      addChildren: vi.fn(),
+      addChild: vi.fn(),
+    };
+
+    batchAddChildren(container as any, [a, a, b]);
+
+    expect(container.addChildren).toHaveBeenCalledTimes(1);
+    expect(container.addChildren).toHaveBeenCalledWith([a, b]);
+    expect(container.addChild).not.toHaveBeenCalled();
+  });
+
+  test('batchRemoveChildren falls back to container.removeChild and deduplicates', () => {
+    const a = createElement('a') as unknown as GfxModel;
+    const b = createElement('b') as unknown as GfxModel;
+    const container = {
+      removeChild: vi.fn(),
+    };
+
+    batchRemoveChildren(container as any, [a, a, b]);
+
+    expect(container.removeChild).toHaveBeenCalledTimes(2);
+    expect(container.removeChild).toHaveBeenNthCalledWith(1, a);
+    expect(container.removeChild).toHaveBeenNthCalledWith(2, b);
+  });
+
+  test('getTopElements removes descendants when ancestors are selected', () => {
+    const root = createGroup('root');
+    const nested = createGroup('nested');
+    const leafA = createElement('leaf-a');
+    const leafB = createElement('leaf-b');
+    const leafC = createElement('leaf-c');
+
+    root.addChild(leafA as unknown as GfxModel);
+    root.addChild(nested as unknown as GfxModel);
+    nested.addChild(leafB as unknown as GfxModel);
+
+    const result = getTopElements([
+      root as unknown as GfxModel,
+      nested as unknown as GfxModel,
+      leafA as unknown as GfxModel,
+      leafB as unknown as GfxModel,
+      leafC as unknown as GfxModel,
+    ]);
+
+    expect(result).toEqual([
+      root as unknown as GfxModel,
+      leafC as unknown as GfxModel,
+    ]);
+  });
+
+  test('descendantElementsImpl stops on cyclic graph', () => {
+    const groupA = createGroup('group-a');
+    const groupB = createGroup('group-b');
+    groupA.addChild(groupB as unknown as GfxModel);
+    groupB.addChild(groupA as unknown as GfxModel);
+
+    const descendants = descendantElementsImpl(groupA as unknown as any);
+
+    expect(descendants).toHaveLength(2);
+    expect(new Set(descendants).size).toBe(2);
+  });
+
+  test('canSafeAddToContainer blocks self and circular descendants', () => {
+    const parent = createGroup('parent');
+    const child = createGroup('child');
+    const unrelated = createElement('plain');
+
+    parent.addChild(child as unknown as GfxModel);
+
+    expect(
+      canSafeAddToContainer(parent as unknown as any, parent as unknown as any)
+    ).toBe(false);
+    expect(
+      canSafeAddToContainer(child as unknown as any, parent as unknown as any)
+    ).toBe(false);
+    expect(
+      canSafeAddToContainer(
+        parent as unknown as any,
+        unrelated as unknown as any
+      )
+    ).toBe(true);
+  });
+});

blocksuite/framework/std/src/gfx/index.ts

@@ -5,6 +5,8 @@ export {
   SortOrder,
 } from '../utils/layer.js';
 export {
+  batchAddChildren,
+  batchRemoveChildren,
   canSafeAddToContainer,
   descendantElementsImpl,
   getTopElements,
@@ -94,6 +96,8 @@ export {
   type SurfaceBlockProps,
   type SurfaceMiddleware,
 } from './model/surface/surface-model.js';
+export { measureOperation } from './perf.js';
+export { createRafCoalescer, type RafCoalescer } from './raf-coalescer.js';
 export { GfxSelectionManager } from './selection.js';
 export {
   SurfaceMiddlewareBuilder,

blocksuite/framework/std/src/gfx/interactivity/manager.ts

@@ -11,6 +11,7 @@ import { GfxExtension, GfxExtensionIdentifier } from '../extension.js';
 import { GfxBlockElementModel } from '../model/gfx-block-model.js';
 import type { GfxModel } from '../model/model.js';
 import { GfxPrimitiveElementModel } from '../model/surface/element-model.js';
+import { createRafCoalescer } from '../raf-coalescer.js';
 import type { GfxElementModelView } from '../view/view.js';
 import { createInteractionContext, type SupportedEvents } from './event.js';
 import {
@@ -55,6 +56,20 @@ export const InteractivityIdentifier = GfxExtensionIdentifier(
   'interactivity-manager'
 ) as ServiceIdentifier<InteractivityManager>;
 
+const DRAG_MOVE_RAF_THRESHOLD = 100;
+const DRAG_MOVE_HEAVY_COST_MS = 4;
+
+const shouldAllowDragMoveCoalescing = (
+  elements: { model: GfxModel }[]
+): boolean => {
+  return elements.every(({ model }) => {
+    const isConnector = 'type' in model && model.type === 'connector';
+    const isContainer = 'childIds' in model;
+
+    return !isConnector && !isContainer;
+  });
+};
+
 export class InteractivityManager extends GfxExtension {
   static override key = 'interactivity-manager';
 
@@ -381,11 +396,18 @@ export class InteractivityManager extends GfxExtension {
     };
     let dragLastPos = internal.dragStartPos;
     let lastEvent = event;
+    let lastMoveDelta: [number, number] | null = null;
+    const canCoalesceDragMove = shouldAllowDragMoveCoalescing(
+      internal.elements
+    );
+    let shouldCoalesceDragMove =
+      canCoalesceDragMove &&
+      internal.elements.length >= DRAG_MOVE_RAF_THRESHOLD;
+
+    const applyDragMove = (event: PointerEvent) => {
+      const moveStart = performance.now();
+      lastEvent = event;
 
-    const viewportWatcher = this.gfx.viewport.viewportMoved.subscribe(() => {
-      onDragMove(lastEvent as PointerEvent);
-    });
-    const onDragMove = (event: PointerEvent) => {
       dragLastPos = Point.from(
         this.gfx.viewport.toModelCoordFromClientCoord([event.x, event.y])
       );
@@ -407,6 +429,16 @@ export class InteractivityManager extends GfxExtension {
         moveContext[direction] = 0;
       }
 
+      if (
+        lastMoveDelta &&
+        lastMoveDelta[0] === moveContext.dx &&
+        lastMoveDelta[1] === moveContext.dy
+      ) {
+        return;
+      }
+
+      lastMoveDelta = [moveContext.dx, moveContext.dy];
+
       this._safeExecute(() => {
         activeExtensionHandlers.forEach(handler =>
           handler?.onDragMove?.(moveContext)
@@ -423,13 +455,39 @@ export class InteractivityManager extends GfxExtension {
           elements: internal.elements,
         });
       });
+
+      if (
+        canCoalesceDragMove &&
+        !shouldCoalesceDragMove &&
+        performance.now() - moveStart > DRAG_MOVE_HEAVY_COST_MS
+      ) {
+        shouldCoalesceDragMove = true;
+      }
     };
+
+    const dragMoveCoalescer = createRafCoalescer<PointerEvent>(applyDragMove);
+
+    const flushPendingDragMove = () => {
+      dragMoveCoalescer.flush();
+    };
+    const onDragMove = (event: PointerEvent) => {
+      if (!shouldCoalesceDragMove) {
+        applyDragMove(event);
+        return;
+      }
+
+      dragMoveCoalescer.schedule(event);
+    };
+    const viewportWatcher = this.gfx.viewport.viewportMoved.subscribe(() => {
+      onDragMove(lastEvent as PointerEvent);
+    });
     const onDragEnd = (event: PointerEvent) => {
       this.activeInteraction$.value = null;
 
       host.removeEventListener('pointermove', onDragMove, false);
       host.removeEventListener('pointerup', onDragEnd, false);
       viewportWatcher.unsubscribe();
+      flushPendingDragMove();
 
       dragLastPos = Point.from(
         this.gfx.viewport.toModelCoordFromClientCoord([event.x, event.y])

blocksuite/framework/std/src/gfx/layer.ts

@@ -101,6 +101,8 @@ export class LayerManager extends GfxExtension {
 
   layers: Layer[] = [];
 
+  private readonly _groupChildSnapshot = new Map<string, string[]>();
+
   slots = {
     layerUpdated: new Subject<{
       type: 'delete' | 'add' | 'update';
@@ -148,6 +150,43 @@ export class LayerManager extends GfxExtension {
       : 'block';
   }
 
+  private _getModelById(id: string): GfxModel | null {
+    if (!this._surface) return null;
+
+    return (
+      this._surface.getElementById(id) ??
+      (this._doc.getModelById(id) as GfxModel | undefined) ??
+      null
+    );
+  }
+
+  private _getRelatedGroupElements(
+    group: GfxModel & GfxGroupCompatibleInterface,
+    oldChildIds?: string[]
+  ) {
+    const elements = new Set<GfxModel>([group, ...group.descendantElements]);
+
+    oldChildIds?.forEach(id => {
+      const model = this._getModelById(id);
+      if (!model) return;
+
+      elements.add(model);
+      if (isGfxGroupCompatibleModel(model)) {
+        model.descendantElements.forEach(descendant => {
+          elements.add(descendant);
+        });
+      }
+    });
+
+    return [...elements];
+  }
+
+  private _syncGroupChildSnapshot(
+    group: GfxModel & GfxGroupCompatibleInterface
+  ) {
+    this._groupChildSnapshot.set(group.id, [...group.childIds]);
+  }
+
   private _initLayers() {
     let blockIdx = 0;
     let canvasIdx = 0;
@@ -487,6 +526,29 @@ export class LayerManager extends GfxExtension {
     updateLayersZIndex(layers, index);
   }
 
+  private _refreshElementsInLayer(elements: GfxModel[]) {
+    const uniqueElements = [...new Set(elements)];
+
+    uniqueElements.forEach(element => {
+      const modelType = this._getModelType(element);
+      if (modelType === 'canvas') {
+        removeFromOrderedArray(this.canvasElements, element);
+        insertToOrderedArray(this.canvasElements, element);
+      } else {
+        removeFromOrderedArray(this.blocks, element);
+        insertToOrderedArray(this.blocks, element);
+      }
+    });
+
+    uniqueElements.forEach(element => {
+      this._removeFromLayer(element, this._getModelType(element));
+    });
+
+    uniqueElements.sort(compare).forEach(element => {
+      this._insertIntoLayer(element, this._getModelType(element));
+    });
+  }
+
   private _reset() {
     const elements = (
       this._doc
@@ -512,6 +574,17 @@ export class LayerManager extends GfxExtension {
 
     this.canvasElements.sort(compare);
     this.blocks.sort(compare);
+    this._groupChildSnapshot.clear();
+    this.canvasElements.forEach(element => {
+      if (isGfxGroupCompatibleModel(element)) {
+        this._syncGroupChildSnapshot(element);
+      }
+    });
+    this.blocks.forEach(element => {
+      if (isGfxGroupCompatibleModel(element)) {
+        this._syncGroupChildSnapshot(element);
+      }
+    });
 
     this._initLayers();
     this._buildCanvasLayers();
@@ -522,7 +595,8 @@ export class LayerManager extends GfxExtension {
    */
   private _updateLayer(
     element: GfxModel | GfxLocalElementModel,
-    props?: Record<string, unknown>
+    props?: Record<string, unknown>,
+    oldValues?: Record<string, unknown>
   ) {
     const modelType = this._getModelType(element);
     const isLocalElem = element instanceof GfxLocalElementModel;
@@ -539,7 +613,16 @@ export class LayerManager extends GfxExtension {
     };
 
     if (shouldUpdateGroupChildren) {
-      this._reset();
+      const group = element as GfxModel & GfxGroupCompatibleInterface;
+      const oldChildIds = childIdsChanged
+        ? Array.isArray(oldValues?.['childIds'])
+          ? (oldValues['childIds'] as string[])
+          : this._groupChildSnapshot.get(group.id)
+        : undefined;
+
+      const relatedElements = this._getRelatedGroupElements(group, oldChildIds);
+      this._refreshElementsInLayer(relatedElements);
+      this._syncGroupChildSnapshot(group);
       return true;
     }
 
@@ -581,6 +664,13 @@ export class LayerManager extends GfxExtension {
         element
       );
     }
+
+    if (isContainer) {
+      this._syncGroupChildSnapshot(
+        element as GfxModel & GfxGroupCompatibleInterface
+      );
+    }
+
     this._insertIntoLayer(element as GfxModel, modelType);
 
     if (isContainer) {
@@ -648,7 +738,26 @@ export class LayerManager extends GfxExtension {
     const isLocalElem = element instanceof GfxLocalElementModel;
 
     if (isGroup) {
-      this._reset();
+      const groupElements = this._getRelatedGroupElements(
+        element as GfxModel & GfxGroupCompatibleInterface
+      );
+      const descendants = groupElements.filter(model => model !== element);
+
+      if (!isLocalElem) {
+        const groupType = this._getModelType(element);
+        if (groupType === 'canvas') {
+          removeFromOrderedArray(this.canvasElements, element);
+        } else {
+          removeFromOrderedArray(this.blocks, element);
+        }
+
+        this._removeFromLayer(element, groupType);
+      }
+
+      this._groupChildSnapshot.delete(element.id);
+
+      this._refreshElementsInLayer(descendants);
+      this._buildCanvasLayers();
       this.slots.layerUpdated.next({
         type: 'delete',
         initiatingElement: element as GfxModel,
@@ -680,6 +789,7 @@ export class LayerManager extends GfxExtension {
 
   override unmounted() {
     this.slots.layerUpdated.complete();
+    this._groupChildSnapshot.clear();
     this._disposable.dispose();
   }
 
@@ -777,9 +887,10 @@ export class LayerManager extends GfxExtension {
 
   update(
     element: GfxModel | GfxLocalElementModel,
-    props?: Record<string, unknown>
+    props?: Record<string, unknown>,
+    oldValues?: Record<string, unknown>
   ) {
-    if (this._updateLayer(element, props)) {
+    if (this._updateLayer(element, props, oldValues)) {
       this._buildCanvasLayers();
       this.slots.layerUpdated.next({
         type: 'update',
@@ -867,7 +978,11 @@ export class LayerManager extends GfxExtension {
       this._disposable.add(
         surface.elementUpdated.subscribe(payload => {
           if (payload.props['index'] || payload.props['childIds']) {
-            this.update(surface.getElementById(payload.id)!, payload.props);
+            this.update(
+              surface.getElementById(payload.id)!,
+              payload.props,
+              payload.oldValues
+            );
           }
         })
       );

blocksuite/framework/std/src/gfx/model/surface/surface-model.ts

@@ -6,6 +6,7 @@ import { signal } from '@preact/signals-core';
 import { Subject } from 'rxjs';
 import * as Y from 'yjs';
 
+import { measureOperation } from '../../perf.js';
 import {
   type GfxGroupCompatibleInterface,
   isGfxGroupCompatibleModel,
@@ -74,6 +75,10 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
 
   protected _groupLikeModels = new Map<string, GfxGroupModel>();
 
+  protected _parentGroupMap = new Map<string, string>();
+
+  protected _groupChildIdsMap = new Map<string, string[]>();
+
   protected _middlewares: SurfaceMiddleware[] = [];
 
   protected _surfaceBlockModel = true;
@@ -133,6 +138,44 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
     });
   }
 
+  private _collectElementsToDelete(
+    id: string,
+    deleteElementIds: Set<string>,
+    orderedDeleteIds: string[],
+    deleteBlockIds: Set<string>
+  ) {
+    if (deleteElementIds.has(id)) {
+      return;
+    }
+
+    const element = this.getElementById(id);
+    if (!element) {
+      return;
+    }
+
+    deleteElementIds.add(id);
+
+    if (element instanceof GfxGroupLikeElementModel) {
+      element.childIds.forEach(childId => {
+        if (this.hasElementById(childId)) {
+          this._collectElementsToDelete(
+            childId,
+            deleteElementIds,
+            orderedDeleteIds,
+            deleteBlockIds
+          );
+          return;
+        }
+
+        if (this.store.hasBlock(childId)) {
+          deleteBlockIds.add(childId);
+        }
+      });
+    }
+
+    orderedDeleteIds.push(id);
+  }
+
   private _createElementFromProps(
     props: Record<string, unknown>,
     options: {
@@ -247,6 +290,26 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
     };
   }
 
+  private _emitElementUpdated(
+    model: GfxPrimitiveElementModel,
+    payload: ElementUpdatedData
+  ) {
+    if (
+      isGfxGroupCompatibleModel(model) &&
+      ('childIds' in payload.props || 'childIds' in payload.oldValues)
+    ) {
+      const oldChildIds = Array.isArray(payload.oldValues['childIds'])
+        ? (payload.oldValues['childIds'] as string[])
+        : undefined;
+      this._syncGroupChildrenIndex(model.id, model.childIds, oldChildIds);
+    }
+
+    this.elementUpdated.next(payload);
+    Object.keys(payload.props).forEach(key => {
+      model.propsUpdated.next({ key });
+    });
+  }
+
   private _initElementModels() {
     const elementsYMap = this.elements.getValue()!;
     const addToType = (type: string, model: GfxPrimitiveElementModel) => {
@@ -260,6 +323,7 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
 
       if (isGfxGroupCompatibleModel(model)) {
         this._groupLikeModels.set(model.id, model);
+        this._syncGroupChildrenIndex(model.id, model.childIds, []);
       }
     };
     const removeFromType = (type: string, model: GfxPrimitiveElementModel) => {
@@ -270,7 +334,10 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
         sameTypeElements.splice(index, 1);
       }
 
-      if (this._groupLikeModels.has(model.id)) {
+      this._parentGroupMap.delete(model.id);
+
+      if (isGfxGroupCompatibleModel(model)) {
+        this._removeGroupFromChildrenIndex(model.id);
         this._groupLikeModels.delete(model.id);
       }
     };
@@ -304,9 +371,9 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
                     element,
                     {
                       onChange: payload => {
-                        this.elementUpdated.next(payload);
+                        this._emitElementUpdated(model.model, {
-                        Object.keys(payload.props).forEach(key => {
+                          ...payload,
-                          model.model.propsUpdated.next({ key });
+                          id,
                         });
                       },
                       skipFieldInit: true,
@@ -351,10 +418,10 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
         val,
         {
           onChange: payload => {
-            (this.elementUpdated.next(payload),
+            this._emitElementUpdated(model.model, {
-              Object.keys(payload.props).forEach(key => {
+              ...payload,
-                model.model.propsUpdated.next({ key });
+              id: key,
-              }));
+            });
           },
           skipFieldInit: true,
         }
@@ -371,9 +438,12 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
     Object.values(this.store.blocks.peek()).forEach(block => {
       if (isGfxGroupCompatibleModel(block.model)) {
         this._groupLikeModels.set(block.id, block.model);
+        this._syncGroupChildrenIndex(block.id, block.model.childIds, []);
       }
     });
 
+    this._rebuildGroupChildrenIndex();
+
     elementsYMap.observe(onElementsMapChange);
 
     const subscription = this.store.slots.blockUpdated.subscribe(payload => {
@@ -381,11 +451,17 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
         case 'add':
           if (isGfxGroupCompatibleModel(payload.model)) {
             this._groupLikeModels.set(payload.id, payload.model);
+            this._syncGroupChildrenIndex(
+              payload.id,
+              payload.model.childIds,
+              []
+            );
           }
 
           break;
         case 'delete':
           if (isGfxGroupCompatibleModel(payload.model)) {
+            this._removeGroupFromChildrenIndex(payload.id);
             this._groupLikeModels.delete(payload.id);
           }
           {
@@ -395,6 +471,16 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
               group.removeChild(payload.model as GfxModel);
             }
           }
+          this._parentGroupMap.delete(payload.id);
+
+          break;
+        case 'update':
+          if (payload.props.key === 'childElementIds') {
+            const group = this.store.getBlock(payload.id)?.model;
+            if (group && isGfxGroupCompatibleModel(group)) {
+              this._syncGroupChildrenIndex(group.id, group.childIds);
+            }
+          }
 
           break;
       }
@@ -403,6 +489,8 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
     this.deleted.subscribe(() => {
       elementsYMap.unobserve(onElementsMapChange);
       subscription.unsubscribe();
+      this._groupChildIdsMap.clear();
+      this._parentGroupMap.clear();
     });
   }
 
@@ -500,6 +588,71 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
     return this._elementCtorMap[type];
   }
 
+  private _rebuildGroupChildrenIndex() {
+    this._groupChildIdsMap.clear();
+    this._parentGroupMap.clear();
+
+    this._groupLikeModels.forEach(group => {
+      this._syncGroupChildrenIndex(group.id, group.childIds, []);
+    });
+  }
+
+  private _removeFromParentGroupIfNeeded(
+    element: GfxModel,
+    deleteElementIds: Set<string>
+  ) {
+    const parentGroupId = this._parentGroupMap.get(element.id);
+
+    if (parentGroupId && deleteElementIds.has(parentGroupId)) {
+      return;
+    }
+
+    let parentGroup: GfxGroupModel | null = null;
+
+    if (parentGroupId) {
+      parentGroup = this._groupLikeModels.get(parentGroupId) ?? null;
+    }
+
+    parentGroup = parentGroup ?? this.getGroup(element.id);
+
+    if (parentGroup && !deleteElementIds.has(parentGroup.id)) {
+      // oxlint-disable-next-line unicorn/prefer-dom-node-remove
+      parentGroup.removeChild(element);
+    }
+  }
+
+  private _removeGroupFromChildrenIndex(groupId: string) {
+    const previousChildIds = this._groupChildIdsMap.get(groupId) ?? [];
+
+    previousChildIds.forEach(childId => {
+      if (this._parentGroupMap.get(childId) === groupId) {
+        this._parentGroupMap.delete(childId);
+      }
+    });
+
+    this._groupChildIdsMap.delete(groupId);
+  }
+
+  private _syncGroupChildrenIndex(
+    groupId: string,
+    nextChildIds: string[],
+    previousChildIds?: string[]
+  ) {
+    const prev = previousChildIds ?? this._groupChildIdsMap.get(groupId) ?? [];
+
+    prev.forEach(childId => {
+      if (this._parentGroupMap.get(childId) === groupId) {
+        this._parentGroupMap.delete(childId);
+      }
+    });
+
+    nextChildIds.forEach(childId => {
+      this._parentGroupMap.set(childId, groupId);
+    });
+
+    this._groupChildIdsMap.set(groupId, [...nextChildIds]);
+  }
+
   addElement<T extends object = Record<string, unknown>>(
     props: Partial<T> & { type: string }
   ) {
@@ -526,9 +679,9 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
 
     const elementModel = this._createElementFromProps(props, {
       onChange: payload => {
-        this.elementUpdated.next(payload);
+        this._emitElementUpdated(elementModel.model, {
-        Object.keys(payload.props).forEach(key => {
+          ...payload,
-          elementModel.model.propsUpdated.next({ key });
+          id,
         });
       },
     });
@@ -560,24 +713,48 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
       return;
     }
 
+    measureOperation('edgeless:delete-element', () => {
+      const deleteElementIds = new Set<string>();
+      const orderedDeleteIds: string[] = [];
+      const deleteBlockIds = new Set<string>();
+
+      this._collectElementsToDelete(
+        id,
+        deleteElementIds,
+        orderedDeleteIds,
+        deleteBlockIds
+      );
+
+      if (orderedDeleteIds.length === 0) {
+        return;
+      }
+
       this.store.transact(() => {
-      const element = this.getElementById(id)!;
+        orderedDeleteIds.forEach(elementId => {
-      const group = this.getGroup(id);
+          const element = this.getElementById(elementId);
 
-      if (element instanceof GfxGroupLikeElementModel) {
+          if (!element) {
-        element.childIds.forEach(childId => {
+            return;
-          if (this.hasElementById(childId)) {
-            this.deleteElement(childId);
-          } else if (this.store.hasBlock(childId)) {
-            this.store.deleteBlock(this.store.getBlock(childId)!.model);
           }
+
+          this._removeFromParentGroupIfNeeded(element, deleteElementIds);
+          this.elements.getValue()!.delete(elementId);
         });
+
+        deleteBlockIds.forEach(blockId => {
+          const block = this.store.getBlock(blockId)?.model;
+
+          if (!block) {
+            return;
           }
 
-      // oxlint-disable-next-line unicorn/prefer-dom-node-remove
+          this._removeFromParentGroupIfNeeded(
-      group?.removeChild(element as GfxModel);
+            block as GfxModel,
-
+            deleteElementIds
-      this.elements.getValue()!.delete(id);
+          );
+          this.store.deleteBlock(block);
+        });
+      });
     });
   }
 
@@ -607,18 +784,31 @@ export class SurfaceBlockModel extends BlockModel<SurfaceBlockProps> {
   }
 
   getGroup(elem: string | GfxModel): GfxGroupModel | null {
-    elem =
+    const id = typeof elem === 'string' ? elem : elem.id;
+    const parentGroupId = this._parentGroupMap.get(id);
+
+    if (parentGroupId) {
+      const group = this._groupLikeModels.get(parentGroupId);
+      if (group) {
+        return group;
+      }
+
+      this._parentGroupMap.delete(id);
+    }
+
+    const model =
       typeof elem === 'string'
         ? ((this.getElementById(elem) ??
             this.store.getBlock(elem)?.model) as GfxModel)
         : elem;
 
-    if (!elem) return null;
+    if (!model) return null;
 
-    assertType<GfxModel>(elem);
+    assertType<GfxModel>(model);
 
     for (const group of this._groupLikeModels.values()) {
-      if (group.hasChild(elem)) {
+      if (group.hasChild(model)) {
+        this._parentGroupMap.set(id, group.id);
         return group;
       }
     }

blocksuite/framework/std/src/gfx/perf.ts

@@ -0,0 +1,31 @@
+let opMeasureSeq = 0;
+
+/**
+ * Measure operation cost via Performance API when available.
+ *
+ * Marks are always cleared, while measure entries are intentionally retained
+ * so callers can inspect them from Performance tools.
+ */
+export const measureOperation = <T>(name: string, fn: () => T): T => {
+  if (
+    typeof performance === 'undefined' ||
+    typeof performance.mark !== 'function' ||
+    typeof performance.measure !== 'function'
+  ) {
+    return fn();
+  }
+
+  const operationId = opMeasureSeq++;
+  const startMark = `${name}:${operationId}:start`;
+  const endMark = `${name}:${operationId}:end`;
+  performance.mark(startMark);
+
+  try {
+    return fn();
+  } finally {
+    performance.mark(endMark);
+    performance.measure(name, startMark, endMark);
+    performance.clearMarks(startMark);
+    performance.clearMarks(endMark);
+  }
+};

blocksuite/framework/std/src/gfx/raf-coalescer.ts

@@ -0,0 +1,76 @@
+export interface RafCoalescer<T> {
+  cancel: () => void;
+  flush: () => void;
+  schedule: (payload: T) => void;
+}
+
+type FrameScheduler = (callback: FrameRequestCallback) => number;
+type FrameCanceller = (id: number) => void;
+
+const getFrameScheduler = (): FrameScheduler => {
+  if (typeof requestAnimationFrame === 'function') {
+    return requestAnimationFrame;
+  }
+
+  return callback => {
+    return globalThis.setTimeout(() => {
+      callback(
+        typeof performance !== 'undefined' ? performance.now() : Date.now()
+      );
+    }, 16) as unknown as number;
+  };
+};
+
+const getFrameCanceller = (): FrameCanceller => {
+  if (typeof cancelAnimationFrame === 'function') {
+    return cancelAnimationFrame;
+  }
+
+  return id => globalThis.clearTimeout(id);
+};
+
+/**
+ * Coalesce high-frequency updates and only process the latest payload in one frame.
+ */
+export const createRafCoalescer = <T>(
+  apply: (payload: T) => void
+): RafCoalescer<T> => {
+  const scheduleFrame = getFrameScheduler();
+  const cancelFrame = getFrameCanceller();
+
+  let pendingPayload: T | undefined;
+  let hasPendingPayload = false;
+  let rafId: number | null = null;
+
+  const run = () => {
+    rafId = null;
+    if (!hasPendingPayload) return;
+
+    const payload = pendingPayload as T;
+    pendingPayload = undefined;
+    hasPendingPayload = false;
+    apply(payload);
+  };
+
+  return {
+    schedule(payload: T) {
+      pendingPayload = payload;
+      hasPendingPayload = true;
+
+      if (rafId !== null) return;
+      rafId = scheduleFrame(run);
+    },
+    flush() {
+      if (rafId !== null) cancelFrame(rafId);
+      run();
+    },
+    cancel() {
+      if (rafId !== null) {
+        cancelFrame(rafId);
+        rafId = null;
+      }
+      pendingPayload = undefined;
+      hasPendingPayload = false;
+    },
+  };
+};

blocksuite/framework/std/src/gfx/viewport-element.ts

@@ -41,6 +41,10 @@ export function requestThrottledConnectedFrame<
   viewport: PropTypes.instanceOf(Viewport),
 })
 export class GfxViewportElement extends WithDisposable(ShadowlessElement) {
+  private static readonly VIEWPORT_REFRESH_PIXEL_THRESHOLD = 18;
+
+  private static readonly VIEWPORT_REFRESH_MAX_INTERVAL = 120;
+
   static override styles = css`
     gfx-viewport {
       position: absolute;
@@ -104,6 +108,14 @@ export class GfxViewportElement extends WithDisposable(ShadowlessElement) {
 
   private _lastVisibleModels?: Set<GfxBlockElementModel>;
 
+  private _lastViewportUpdate?: { zoom: number; center: [number, number] };
+
+  private _lastViewportRefreshTime = 0;
+
+  private _pendingViewportRefreshTimer: ReturnType<
+    typeof globalThis.setTimeout
+  > | null = null;
+
   private readonly _pendingChildrenUpdates: {
     id: string;
     resolve: () => void;
@@ -115,26 +127,90 @@ export class GfxViewportElement extends WithDisposable(ShadowlessElement) {
 
   private _updatingChildrenFlag = false;
 
+  private _clearPendingViewportRefreshTimer() {
+    if (this._pendingViewportRefreshTimer !== null) {
+      clearTimeout(this._pendingViewportRefreshTimer);
+      this._pendingViewportRefreshTimer = null;
+    }
+  }
+
+  private _scheduleTrailingViewportRefresh() {
+    this._clearPendingViewportRefreshTimer();
+    this._pendingViewportRefreshTimer = globalThis.setTimeout(() => {
+      this._pendingViewportRefreshTimer = null;
+      this._lastViewportRefreshTime = performance.now();
+      this._refreshViewport();
+    }, GfxViewportElement.VIEWPORT_REFRESH_MAX_INTERVAL);
+  }
+
+  private _refreshViewportByViewportUpdate(update: {
+    zoom: number;
+    center: [number, number];
+  }) {
+    const now = performance.now();
+    const previous = this._lastViewportUpdate;
+    this._lastViewportUpdate = {
+      zoom: update.zoom,
+      center: [update.center[0], update.center[1]],
+    };
+
+    if (!previous) {
+      this._lastViewportRefreshTime = now;
+      this._refreshViewport();
+      return;
+    }
+
+    const zoomChanged = Math.abs(previous.zoom - update.zoom) > 0.0001;
+    const centerMovedInPixel = Math.hypot(
+      (update.center[0] - previous.center[0]) * update.zoom,
+      (update.center[1] - previous.center[1]) * update.zoom
+    );
+    const timeoutReached =
+      now - this._lastViewportRefreshTime >=
+      GfxViewportElement.VIEWPORT_REFRESH_MAX_INTERVAL;
+
+    if (
+      zoomChanged ||
+      centerMovedInPixel >=
+        GfxViewportElement.VIEWPORT_REFRESH_PIXEL_THRESHOLD ||
+      timeoutReached
+    ) {
+      this._clearPendingViewportRefreshTimer();
+      this._lastViewportRefreshTime = now;
+      this._refreshViewport();
+      return;
+    }
+
+    this._scheduleTrailingViewportRefresh();
+  }
+
   override connectedCallback(): void {
     super.connectedCallback();
 
-    const viewportUpdateCallback = () => {
-      this._refreshViewport();
-    };
-
     if (!this.enableChildrenSchedule) {
       delete this.scheduleUpdateChildren;
     }
 
     this._hideOutsideAndNoSelectedBlock();
     this.disposables.add(
-      this.viewport.viewportUpdated.subscribe(() => viewportUpdateCallback())
+      this.viewport.viewportUpdated.subscribe(update =>
+        this._refreshViewportByViewportUpdate(update)
+      )
     );
     this.disposables.add(
-      this.viewport.sizeUpdated.subscribe(() => viewportUpdateCallback())
+      this.viewport.sizeUpdated.subscribe(() => {
+        this._clearPendingViewportRefreshTimer();
+        this._lastViewportRefreshTime = performance.now();
+        this._refreshViewport();
+      })
     );
   }
 
+  override disconnectedCallback(): void {
+    this._clearPendingViewportRefreshTimer();
+    super.disconnectedCallback();
+  }
+
   override render() {
     return html``;
   }

blocksuite/framework/std/src/utils/tree.ts

@@ -7,6 +7,11 @@ import {
 } from '../gfx/model/base.js';
 import type { GfxGroupModel, GfxModel } from '../gfx/model/model.js';
 
+type BatchGroupContainer = GfxGroupCompatibleInterface & {
+  addChildren?: (elements: GfxModel[]) => void;
+  removeChildren?: (elements: GfxModel[]) => void;
+};
+
 /**
  * Get the top elements from the list of elements, which are in some tree structures.
  *
@@ -26,19 +31,64 @@ import type { GfxGroupModel, GfxModel } from '../gfx/model/model.js';
  * The result should be `[G1, G4, E6]`
  */
 export function getTopElements(elements: GfxModel[]): GfxModel[] {
-  const results = new Set(elements);
+  const uniqueElements = [...new Set(elements)];
+  const selected = new Set(uniqueElements);
+  const topElements: GfxModel[] = [];
 
-  elements = [...new Set(elements)];
+  for (const element of uniqueElements) {
+    let ancestor = element.group;
+    let hasSelectedAncestor = false;
 
-  elements.forEach(e1 => {
+    while (ancestor) {
-    elements.forEach(e2 => {
+      if (selected.has(ancestor as GfxModel)) {
-      if (isGfxGroupCompatibleModel(e1) && e1.hasDescendant(e2)) {
+        hasSelectedAncestor = true;
-        results.delete(e2);
+        break;
+      }
+      ancestor = ancestor.group;
     }
-    });
-  });
 
-  return [...results];
+    if (!hasSelectedAncestor) {
+      topElements.push(element);
+    }
+  }
+
+  return topElements;
+}
+
+export function batchAddChildren(
+  container: GfxGroupCompatibleInterface,
+  elements: GfxModel[]
+) {
+  const uniqueElements = [...new Set(elements)];
+  if (uniqueElements.length === 0) return;
+
+  const batchContainer = container as BatchGroupContainer;
+  if (batchContainer.addChildren) {
+    batchContainer.addChildren(uniqueElements);
+    return;
+  }
+
+  uniqueElements.forEach(element => {
+    container.addChild(element);
+  });
+}
+
+export function batchRemoveChildren(
+  container: GfxGroupCompatibleInterface,
+  elements: GfxModel[]
+) {
+  const uniqueElements = [...new Set(elements)];
+  if (uniqueElements.length === 0) return;
+
+  const batchContainer = container as BatchGroupContainer;
+  if (batchContainer.removeChildren) {
+    batchContainer.removeChildren(uniqueElements);
+    return;
+  }
+
+  uniqueElements.forEach(element => {
+    container.removeChild(element);
+  });
 }
 
 function traverse(

blocksuite/integration-test/src/__tests__/edgeless/surface-model.spec.ts

@@ -235,6 +235,69 @@ describe('connector', () => {
     expect(model.getConnectors(id2)).toEqual([]);
   });
 
+  test('should update endpoint index when connector retargets', () => {
+    const id = model.addElement({
+      type: 'shape',
+    });
+    const id2 = model.addElement({
+      type: 'shape',
+    });
+    const id3 = model.addElement({
+      type: 'shape',
+    });
+    const connectorId = model.addElement({
+      type: 'connector',
+      source: {
+        id,
+      },
+      target: {
+        id: id2,
+      },
+    });
+    const connector = model.getElementById(connectorId)!;
+
+    expect(model.getConnectors(id).map(c => c.id)).toEqual([connector.id]);
+    expect(model.getConnectors(id2).map(c => c.id)).toEqual([connector.id]);
+
+    model.updateElement(connectorId, {
+      source: {
+        id: id3,
+      },
+      target: {
+        id: id2,
+      },
+    });
+
+    expect(model.getConnectors(id)).toEqual([]);
+    expect(model.getConnectors(id3).map(c => c.id)).toEqual([connector.id]);
+    expect(model.getConnectors(id2).map(c => c.id)).toEqual([connector.id]);
+  });
+
+  test('getConnectors should purge stale connector ids from endpoint cache', () => {
+    const shapeId = model.addElement({
+      type: 'shape',
+    });
+    const surfaceModel = model as any;
+    surfaceModel._connectorIdsByEndpoint.set(
+      shapeId,
+      new Set(['missing-connector-id'])
+    );
+    surfaceModel._connectorEndpoints.set('missing-connector-id', {
+      sourceId: shapeId,
+      targetId: null,
+    });
+
+    expect(model.getConnectors(shapeId)).toEqual([]);
+    expect(
+      surfaceModel._connectorIdsByEndpoint
+        .get(shapeId)
+        ?.has('missing-connector-id') ?? false
+    ).toBe(false);
+    expect(surfaceModel._connectorEndpoints.has('missing-connector-id')).toBe(
+      false
+    );
+  });
+
   test('should return null if connector are deleted', async () => {
     const id = model.addElement({
       type: 'shape',

yarn.lock

@@ -2684,10 +2684,12 @@ __metadata:
     "@preact/signals-core": "npm:^1.8.0"
     "@toeverything/theme": "npm:^1.1.23"
     "@types/lodash-es": "npm:^4.17.12"
+    fractional-indexing: "npm:^3.2.0"
     lit: "npm:^3.2.0"
     lodash-es: "npm:^4.17.23"
     minimatch: "npm:^10.1.1"
     rxjs: "npm:^7.8.2"
+    vitest: "npm:^3.2.4"
     yjs: "npm:^13.6.27"
     zod: "npm:^3.25.76"
   languageName: unknown
@@ -2814,6 +2816,7 @@ __metadata:
     lodash-es: "npm:^4.17.23"
     minimatch: "npm:^10.1.1"
     rxjs: "npm:^7.8.2"
+    vitest: "npm:^3.2.4"
     yjs: "npm:^13.6.27"
     zod: "npm:^3.25.76"
   languageName: unknown