diff --git a/backend/app/modules/data_process/store.py b/backend/app/modules/data_process/store.py
index e501550..6acb405 100644
--- a/backend/app/modules/data_process/store.py
+++ b/backend/app/modules/data_process/store.py
@@ -3,11 +3,13 @@ from __future__ import annotations
 import hashlib
 import json
 import uuid
+from collections.abc import Iterator, Sequence
 from contextlib import contextmanager
-from datetime import date, datetime, timezone
+from datetime import UTC, date, datetime
+from decimal import Decimal
 from functools import lru_cache
 from pathlib import Path
-from typing import Any, Iterator, Sequence
+from typing import Any
 
 import psycopg
 from psycopg.rows import dict_row
@@ -36,7 +38,7 @@ class InvalidStateError(DataProcessStoreError):
 
 
 def utcnow() -> str:
-    return datetime.now(timezone.utc).replace(microsecond=0).isoformat().replace("+00:00", "Z")
+    return datetime.now(UTC).replace(microsecond=0).isoformat().replace("+00:00", "Z")
 
 
 def new_id(prefix: str) -> str:
@@ -65,6 +67,8 @@ def _json_value(value: Any, default: Any) -> Any:
 def _serialize_value(value: Any) -> Any:
     if isinstance(value, (datetime, date)):
         return value.isoformat().replace("+00:00", "Z")
+    if isinstance(value, Decimal):
+        return float(value)
     return value
 
 
@@ -136,9 +140,8 @@ class DataProcessStore:
         """显式安装数据处理表；API 路由和应用启动流程不会调用此方法。"""
         schema_path = Path(__file__).resolve().parents[2] / "db" / "sql" / "002_data_process.sql"
         sql = schema_path.read_text(encoding="utf-8")
-        with self.connect() as conn:
-            with conn.cursor() as cursor:
-                cursor.execute(sql)
+        with self.connect() as conn, conn.cursor() as cursor:
+            cursor.execute(sql)
 
     def list_tasks(
         self,
@@ -227,10 +230,30 @@ class DataProcessStore:
     def get_task(self, task_id: str, *, for_update: bool = False) -> dict[str, Any]:
         lock = " FOR UPDATE" if for_update else ""
         with self.connect() as conn:
-            row = conn.execute(
-                f"SELECT * FROM data_process_tasks WHERE id=%s AND deleted_at IS NULL{lock}",
-                (task_id,),
-            ).fetchone()
+            if for_update:
+                row = conn.execute(
+                    f"SELECT * FROM data_process_tasks WHERE id=%s AND deleted_at IS NULL{lock}",
+                    (task_id,),
+                ).fetchone()
+            else:
+                row = conn.execute(
+                    """
+                    SELECT task.*,
+                           (SELECT COUNT(*) FROM data_process_source_files source
+                            WHERE source.task_id=task.id AND source.deleted_at IS NULL)
+                             AS source_file_count,
+                           (SELECT COUNT(*) FROM data_process_preview_items preview
+                            WHERE preview.task_id=task.id) AS preview_count,
+                           CASE
+                             WHEN task.started_at IS NOT NULL AND task.completed_at IS NOT NULL
+                             THEN EXTRACT(EPOCH FROM (task.completed_at - task.started_at))
+                             ELSE NULL
+                           END AS duration_seconds
+                    FROM data_process_tasks task
+                    WHERE task.id=%s AND task.deleted_at IS NULL
+                    """,
+                    (task_id,),
+                ).fetchone()
         if not row:
             raise NotFoundError("data process task not found")
         return _decode_row(row) or {}
diff --git a/backend/tests/test_data_process_store.py b/backend/tests/test_data_process_store.py
index 0e7ba29..004504b 100644
--- a/backend/tests/test_data_process_store.py
+++ b/backend/tests/test_data_process_store.py
@@ -1,13 +1,27 @@
 from __future__ import annotations
 
+from decimal import Decimal
+
 import pytest
 
 from app.modules.data_process.store import (
     DataProcessStoreError,
+    _decode_row,
     _source_storage_descriptor,
 )
 
 
+def test_decode_row_serializes_postgres_numeric_values_as_json_numbers() -> None:
+    decoded = _decode_row(
+        {
+            "progress": Decimal("100.00"),
+            "duration_seconds": Decimal("389.000000"),
+        }
+    )
+
+    assert decoded == {"progress": 100.0, "duration_seconds": 389.0}
+
+
 def test_source_storage_descriptor_accepts_owned_local_and_legacy_db_references() -> None:
     task_id = "dpt_task"
     source_file_id = "dpsf_source"