test this new action

Author: Sung Won Chung

.github/workflows/formatter.yml

@@ -10,12 +10,23 @@ jobs:
     name: runner / ruff
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - name: Checkout PR head
+        uses: actions/checkout@v3
+        if: github.event_name == 'pull_request'
+        with:
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
+          ref: ${{ github.event.pull_request.head.ref }}
+
+      - name: Checkout Repo 
+        uses: actions/checkout@v3
+        if: github.event_name == 'workflow_dispatch'
+
       - name: Check files using the ruff formatter
         uses: chartboost/ruff-action@v1
         id: ruff_formatter
         with:
           args: format
+
       - name: Auto commit ruff formatting
         uses: stefanzweifel/git-auto-commit-action@v5
         with:

data_diff/databases/mysql.py

@@ -1,4 +1,4 @@
-from typing import Any, ClassVar, Dict, Type
+from typing import Any, ClassVar, Dict, Type, Union
 
 import attrs
 
@@ -20,6 +20,7 @@
     import_helper,
     ConnectError,
     BaseDialect,
+    ThreadLocalInterpreter,
 )
 from data_diff.databases.base import (
     MD5_HEXDIGITS,
@@ -148,3 +149,14 @@ def create_connection(self):
             elif e.errno == mysql.errorcode.ER_BAD_DB_ERROR:
                 raise ConnectError("Database does not exist") from e
             raise ConnectError(*e.args) from e
+
+    def _query_in_worker(self, sql_code: Union[str, ThreadLocalInterpreter]):
+        "This method runs in a worker thread"
+        if self._init_error:
+            raise self._init_error
+        if not self.thread_local.conn.is_connected():
+            try:
+                self.thread_local.conn.ping(reconnect=True, attempts=3, delay=5)
+            except Exception as e:
+                raise ConnectError(*e.args) from e
+        return self._query_conn(self.thread_local.conn, sql_code)