diff --git a/app/database/services.py b/app/database/services.py
index 0b7e3711c..42f647d91 100644
--- a/app/database/services.py
+++ b/app/database/services.py
@@ -10,6 +10,8 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select, delete, func
 from sqlalchemy.orm import contains_eager, noload
 from sqlalchemy.exc import IntegrityError
+from sqlalchemy.dialects import sqlite as d_sqlite
+from sqlalchemy.dialects import postgresql as d_pg
 
 from .models import Asset, AssetInfo, AssetInfoTag, AssetCacheState, Tag, AssetInfoMeta, AssetLocation
 from .timeutil import utcnow
@@ -143,39 +145,49 @@ async def ingest_fs_asset(
         else:
             logging.error("Asset %s not found after PK conflict; skipping update.", asset_hash)
 
-    # ---- Step 2: INSERT/UPDATE AssetCacheState (mtime_ns, file_path) ----
-    with contextlib.suppress(IntegrityError):
-        async with session.begin_nested():
-            session.add(
-                AssetCacheState(
-                    asset_hash=asset_hash,
-                    file_path=locator,
-                    mtime_ns=int(mtime_ns),
+    # ---- Step 2: UPSERT AssetCacheState (mtime_ns, file_path) ----
+    dialect = session.bind.dialect.name  # "sqlite" or "postgresql"
+    vals = {
+        "asset_hash": asset_hash,
+        "file_path": locator,
+        "mtime_ns": int(mtime_ns),
+    }
+    # 2-step idempotent write so we can set flags deterministically:
+    #   INSERT ... ON CONFLICT(file_path) DO NOTHING
+    #   if conflicted, UPDATE only when values actually change
+    if dialect == "sqlite":
+        ins = (
+            d_sqlite.insert(AssetCacheState)
+            .values(**vals)
+            .on_conflict_do_nothing(index_elements=[AssetCacheState.file_path])
+        )
+    elif dialect == "postgresql":
+        ins = (
+            d_pg.insert(AssetCacheState)
+            .values(**vals)
+            .on_conflict_do_nothing(index_elements=[AssetCacheState.file_path])
+        )
+    else:
+        raise NotImplementedError(f"Unsupported database dialect: {dialect}")
+    res = await session.execute(ins)
+    if int(res.rowcount or 0) > 0:
+        out["state_created"] = True
+    else:
+        upd = (
+            sa.update(AssetCacheState)
+            .where(AssetCacheState.file_path == locator)
+            .where(
+                sa.or_(
+                    AssetCacheState.asset_hash != asset_hash,
+                    AssetCacheState.mtime_ns.is_(None),
+                    AssetCacheState.mtime_ns != int(mtime_ns),
                 )
             )
-            await session.flush()
-            out["state_created"] = True
-
-    if not out["state_created"]:
-        # unique(file_path) conflict -> update that row
-        state = (
-            await session.execute(
-                select(AssetCacheState).where(AssetCacheState.file_path == locator).limit(1)
-            )
-        ).scalars().first()
-        if state is not None:
-            changed = False
-            if state.asset_hash != asset_hash:
-                state.asset_hash = asset_hash
-                changed = True
-            if state.mtime_ns != int(mtime_ns):
-                state.mtime_ns = int(mtime_ns)
-                changed = True
-            if changed:
-                await session.flush()
-                out["state_updated"] = True
-        else:
-            logging.error("Locator state missing for %s after conflict; skipping update.", asset_hash)
+            .values(asset_hash=asset_hash, mtime_ns=int(mtime_ns))
+        )
+        res2 = await session.execute(upd)
+        if int(res2.rowcount or 0) > 0:
+            out["state_updated"] = True
 
     # ---- Optional: AssetInfo + tag links ----
     if info_name: