diff --git a/backend/open_webui/migrations/versions/a749ab2aa953_add_memory_user_id_index.py b/backend/open_webui/migrations/versions/a749ab2aa953_add_memory_user_id_index.py
index 6a54d8d27b..254d49f7bf 100644
--- a/backend/open_webui/migrations/versions/a749ab2aa953_add_memory_user_id_index.py
+++ b/backend/open_webui/migrations/versions/a749ab2aa953_add_memory_user_id_index.py
@@ -7,7 +7,6 @@ Create Date: 2026-04-17 00:00:00.000000
 """
 
 from alembic import op
-import sqlalchemy as sa
 
 revision = 'a749ab2aa953'
 down_revision = 'c1d2e3f4a5b6'
diff --git a/backend/open_webui/models/memories.py b/backend/open_webui/models/memories.py
index 1ec52eeb6a..5de250c1fb 100644
--- a/backend/open_webui/models/memories.py
+++ b/backend/open_webui/models/memories.py
@@ -6,7 +6,7 @@ from sqlalchemy import select, delete
 from sqlalchemy.ext.asyncio import AsyncSession
 from open_webui.internal.db import Base, get_async_db_context
 from pydantic import BaseModel, ConfigDict
-from sqlalchemy import BigInteger, Column, String, Text
+from sqlalchemy import BigInteger, Column, Index, String, Text
 
 ####################
 # Memory DB Schema
@@ -19,11 +19,15 @@ class Memory(Base):
     __tablename__ = 'memory'
 
     id = Column(String, primary_key=True, unique=True)
-    user_id = Column(String, index=True)
+    user_id = Column(String)
     content = Column(Text)
     updated_at = Column(BigInteger)
     created_at = Column(BigInteger)
 
+    __table_args__ = (
+        Index('memory_user_id_idx', 'user_id'),
+    )
+
 
 class MemoryModel(BaseModel):
     id: str