introduce skip_open_order_update parameter

skips startup-open-order-update
closes #4128

docs/configuration.md

@@ -89,6 +89,7 @@ Mandatory parameters are marked as **Required**, which means that they are requi
 | `exchange.ccxt_async_config` | Additional CCXT parameters passed to the async ccxt instance. Parameters may differ from exchange to exchange  and are documented in the [ccxt documentation](https://ccxt.readthedocs.io/en/latest/manual.html#instantiation) <br> **Datatype:** Dict
 | `exchange.markets_refresh_interval` | The interval in minutes in which markets are reloaded. <br>*Defaults to `60` minutes.* <br> **Datatype:** Positive Integer
 | `exchange.skip_pair_validation` | Skip pairlist validation on startup.<br>*Defaults to `false`<br> **Datatype:** Boolean
+| `exchange.skip_open_order_update` | Skips open order updates on startup should the exchange cause problems. Only relevant in live conditions.<br>*Defaults to `false`<br> **Datatype:** Boolean
 | `edge.*` | Please refer to [edge configuration document](edge.md) for detailed explanation.
 | `experimental.block_bad_exchanges` | Block exchanges known to not work with freqtrade. Leave on default unless you want to test if that exchange works now. <br>*Defaults to `true`.* <br> **Datatype:** Boolean
 | `pairlists` | Define one or more pairlists to be used. [More information](plugins.md#pairlists-and-pairlist-handlers). <br>*Defaults to `StaticPairList`.*  <br> **Datatype:** List of Dicts

freqtrade/freqtradebot.py

@@ -246,7 +246,7 @@ class FreqtradeBot(LoggingMixin):
         Updates open orders based on order list kept in the database.
         Mainly updates the state of orders - but may also close trades
         """
-        if self.config['dry_run']:
+        if self.config['dry_run'] or self.config['exchange'].get('skip_open_order_update', False):
             # Updating open orders in dry-run does not make sense and will fail.
             return