Implement database migration to other system

freqtrade/commands/db_commands.py

@@ -1,9 +1,40 @@
+import logging
 from typing import Any, Dict
 
 from freqtrade.configuration.config_setup import setup_utils_configuration
 from freqtrade.enums.runmode import RunMode
 
 
+logger = logging.getLogger(__name__)
+
+
 def start_db_convert(args: Dict[str, Any]) -> None:
+    from sqlalchemy.orm import make_transient
+
+    from freqtrade.persistence import Trade, init_db
+    from freqtrade.persistence.pairlock import PairLock
+
     config = setup_utils_configuration(args, RunMode.UTIL_NO_EXCHANGE)
-    pass
+
+    init_db(config['db_url'], False)
+    session_target = Trade._session
+    init_db(config['db_url_from'], False)
+
+    # print(f"{id(sessionA)=}, {id(sessionB)=}")
+    trade_count = 0
+    pairlock_count = 0
+    for trade in Trade.get_trades():
+        trade_count += 1
+        make_transient(trade)
+        for o in trade.orders:
+            make_transient(o)
+
+        session_target.add(trade)
+    session_target.commit()
+
+    for pairlock in PairLock.query:
+        pairlock_count += 1
+        make_transient(pairlock)
+        session_target.add(pairlock)
+    session_target.commit()
+    logger.info(f"Migrated {trade_count} Trades, and {pairlock_count} Pairlocks.")