diff --git a/apps/server/src/core/base/query-cache/column-types.spec.ts b/apps/server/src/core/base/query-cache/column-types.spec.ts
new file mode 100644
index 00000000..3307c429
--- /dev/null
+++ b/apps/server/src/core/base/query-cache/column-types.spec.ts
@@ -0,0 +1,76 @@
+import { BasePropertyType } from '../base.schemas';
+import { buildColumnSpecs, SYSTEM_COLUMNS } from './column-types';
+
+const p = (type: string, extra: Record<string, unknown> = {}) => ({
+  id: `prop-${type}`,
+  type,
+  typeOptions: extra,
+}) as any;
+
+describe('buildColumnSpecs', () => {
+  it('includes the fixed system columns first', () => {
+    const specs = buildColumnSpecs([]);
+    expect(specs.map((s) => s.column)).toEqual(SYSTEM_COLUMNS.map((s) => s.column));
+  });
+
+  it('maps text / url / email to VARCHAR indexable', () => {
+    for (const t of [BasePropertyType.TEXT, BasePropertyType.URL, BasePropertyType.EMAIL]) {
+      const specs = buildColumnSpecs([p(t)]);
+      const user = specs[specs.length - 1];
+      expect(user.ddlType).toBe('VARCHAR');
+      expect(user.indexable).toBe(true);
+    }
+  });
+
+  it('maps number to DOUBLE indexable', () => {
+    const specs = buildColumnSpecs([p(BasePropertyType.NUMBER)]);
+    const user = specs[specs.length - 1];
+    expect(user.ddlType).toBe('DOUBLE');
+    expect(user.indexable).toBe(true);
+  });
+
+  it('maps date to TIMESTAMPTZ indexable', () => {
+    const specs = buildColumnSpecs([p(BasePropertyType.DATE)]);
+    const user = specs[specs.length - 1];
+    expect(user.ddlType).toBe('TIMESTAMPTZ');
+    expect(user.indexable).toBe(true);
+  });
+
+  it('maps checkbox to BOOLEAN indexable', () => {
+    const specs = buildColumnSpecs([p(BasePropertyType.CHECKBOX)]);
+    const user = specs[specs.length - 1];
+    expect(user.ddlType).toBe('BOOLEAN');
+  });
+
+  it('maps select / status to VARCHAR indexable', () => {
+    for (const t of [BasePropertyType.SELECT, BasePropertyType.STATUS]) {
+      const specs = buildColumnSpecs([p(t)]);
+      const user = specs[specs.length - 1];
+      expect(user.ddlType).toBe('VARCHAR');
+      expect(user.indexable).toBe(true);
+    }
+  });
+
+  it('maps multiSelect / file / multi-person to JSON non-indexable', () => {
+    for (const t of [BasePropertyType.MULTI_SELECT, BasePropertyType.FILE]) {
+      const specs = buildColumnSpecs([p(t)]);
+      const user = specs[specs.length - 1];
+      expect(user.ddlType).toBe('JSON');
+      expect(user.indexable).toBe(false);
+    }
+    const specs = buildColumnSpecs([p(BasePropertyType.PERSON, { allowMultiple: true })]);
+    expect(specs[specs.length - 1].ddlType).toBe('JSON');
+  });
+
+  it('maps single-person to VARCHAR indexable when allowMultiple=false', () => {
+    const specs = buildColumnSpecs([p(BasePropertyType.PERSON, { allowMultiple: false })]);
+    const user = specs[specs.length - 1];
+    expect(user.ddlType).toBe('VARCHAR');
+    expect(user.indexable).toBe(true);
+  });
+
+  it('skips unknown property types', () => {
+    const specs = buildColumnSpecs([p('unknown-type-x')]);
+    expect(specs.length).toBe(SYSTEM_COLUMNS.length);
+  });
+});
diff --git a/apps/server/src/core/base/query-cache/column-types.ts b/apps/server/src/core/base/query-cache/column-types.ts
new file mode 100644
index 00000000..bf84cb19
--- /dev/null
+++ b/apps/server/src/core/base/query-cache/column-types.ts
@@ -0,0 +1,60 @@
+import { BasePropertyType, BasePropertyTypeValue } from '../base.schemas';
+import { ColumnSpec } from './query-cache.types';
+import type { BaseProperty } from '@docmost/db/types/entity.types';
+
+export const SYSTEM_COLUMNS: ColumnSpec[] = [
+  { column: 'id', ddlType: 'VARCHAR', indexable: false },
+  { column: 'position', ddlType: 'VARCHAR', indexable: true },
+  { column: 'created_at', ddlType: 'TIMESTAMPTZ', indexable: true },
+  { column: 'updated_at', ddlType: 'TIMESTAMPTZ', indexable: true },
+  { column: 'last_updated_by_id', ddlType: 'VARCHAR', indexable: true },
+  { column: 'deleted_at', ddlType: 'TIMESTAMPTZ', indexable: false },
+  { column: 'search_text', ddlType: 'VARCHAR', indexable: false },
+];
+
+type PropertyLike = Pick<BaseProperty, 'id' | 'type' | 'typeOptions'>;
+
+export function buildColumnSpecs(properties: PropertyLike[]): ColumnSpec[] {
+  const out: ColumnSpec[] = [...SYSTEM_COLUMNS];
+  for (const prop of properties) {
+    const spec = buildUserColumn(prop);
+    if (spec) out.push(spec);
+  }
+  return out;
+}
+
+function buildUserColumn(prop: PropertyLike): ColumnSpec | null {
+  const t = prop.type as BasePropertyTypeValue;
+  switch (t) {
+    case BasePropertyType.TEXT:
+    case BasePropertyType.URL:
+    case BasePropertyType.EMAIL:
+      return { column: prop.id, ddlType: 'VARCHAR', indexable: true, property: prop };
+    case BasePropertyType.NUMBER:
+      return { column: prop.id, ddlType: 'DOUBLE', indexable: true, property: prop };
+    case BasePropertyType.DATE:
+      return { column: prop.id, ddlType: 'TIMESTAMPTZ', indexable: true, property: prop };
+    case BasePropertyType.CHECKBOX:
+      return { column: prop.id, ddlType: 'BOOLEAN', indexable: true, property: prop };
+    case BasePropertyType.SELECT:
+    case BasePropertyType.STATUS:
+      return { column: prop.id, ddlType: 'VARCHAR', indexable: true, property: prop };
+    case BasePropertyType.MULTI_SELECT:
+    case BasePropertyType.FILE:
+      return { column: prop.id, ddlType: 'JSON', indexable: false, property: prop };
+    case BasePropertyType.PERSON: {
+      const allowMultiple = !!(prop.typeOptions as any)?.allowMultiple;
+      return allowMultiple
+        ? { column: prop.id, ddlType: 'JSON', indexable: false, property: prop }
+        : { column: prop.id, ddlType: 'VARCHAR', indexable: true, property: prop };
+    }
+    // System types are modelled as system columns on base_rows — do not add
+    // a per-property column for them. They're already in SYSTEM_COLUMNS.
+    case BasePropertyType.CREATED_AT:
+    case BasePropertyType.LAST_EDITED_AT:
+    case BasePropertyType.LAST_EDITED_BY:
+      return null;
+    default:
+      return null;
+  }
+}
diff --git a/apps/server/src/core/base/query-cache/query-cache.types.ts b/apps/server/src/core/base/query-cache/query-cache.types.ts
new file mode 100644
index 00000000..0d785d90
--- /dev/null
+++ b/apps/server/src/core/base/query-cache/query-cache.types.ts
@@ -0,0 +1,37 @@
+import type { DuckDBConnection, DuckDBInstance } from '@duckdb/node-api';
+import type { BaseProperty } from '@docmost/db/types/entity.types';
+
+export type DuckDbColumnType =
+  | 'VARCHAR'
+  | 'DOUBLE'
+  | 'BOOLEAN'
+  | 'TIMESTAMPTZ'
+  | 'JSON';
+
+export type ColumnSpec = {
+  // The uuid of the property (user-defined props) or a stable literal
+  // ('id', 'position', 'created_at', 'updated_at', 'last_updated_by_id',
+  //  'deleted_at', 'search_text') for system columns.
+  column: string;
+  ddlType: DuckDbColumnType;
+  indexable: boolean;
+  // For user-defined props we keep the source BaseProperty so callers can
+  // resolve the extraction rule from JSON.
+  property?: Pick<BaseProperty, 'id' | 'type' | 'typeOptions'>;
+};
+
+export type LoadedCollection = {
+  baseId: string;
+  schemaVersion: number;
+  columns: ColumnSpec[];
+  instance: DuckDBInstance;
+  connection: DuckDBConnection;
+  lastAccessedAt: number;
+};
+
+export type ChangeEnvelope =
+  | { kind: 'row-upsert'; baseId: string; row: Record<string, unknown> }
+  | { kind: 'row-delete'; baseId: string; rowId: string }
+  | { kind: 'rows-delete'; baseId: string; rowIds: string[] }
+  | { kind: 'row-reorder'; baseId: string; rowId: string; position: string }
+  | { kind: 'schema-invalidate'; baseId: string; schemaVersion: number };