From 8a7bb6bc5a5b0f63781429a61dca27ceca22a6be Mon Sep 17 00:00:00 2001
From: "nicolas.dorier" <nicolas.dorier@gmail.com>
Date: Wed, 26 Jan 2022 15:09:06 +0900
Subject: [PATCH] Retry SaveChanges if deadlock detected in delete store

---
 .../Services/Stores/StoreRepository.cs         | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/BTCPayServer/Services/Stores/StoreRepository.cs b/BTCPayServer/Services/Stores/StoreRepository.cs
index e37a26950..61eeaf438 100644
--- a/BTCPayServer/Services/Stores/StoreRepository.cs
+++ b/BTCPayServer/Services/Stores/StoreRepository.cs
@@ -328,6 +328,7 @@ namespace BTCPayServer.Services.Stores
 
         public async Task<bool> DeleteStore(string storeId)
         {
+            int retry = 0;
             using var ctx = _ContextFactory.CreateContext();
             if (!ctx.Database.SupportDropForeignKey())
                 return false;
@@ -341,10 +342,25 @@ namespace BTCPayServer.Services.Stores
             foreach (var w in webhooks)
                 ctx.Webhooks.Remove(w);
             ctx.Stores.Remove(store);
-            await ctx.SaveChangesAsync();
+            retry:
+            try
+            {
+                await ctx.SaveChangesAsync();
+            }
+            catch (DbUpdateException ex) when (IsDeadlock(ex) && retry < 5)
+            {
+                await Task.Delay(100);
+                retry++;
+                goto retry;
+            }
             return true;
         }
 
+        private static bool IsDeadlock(DbUpdateException ex)
+        {
+            return ex.InnerException is Npgsql.PostgresException postgres && postgres.SqlState == "40P01";
+        }
+
         public bool CanDeleteStores()
         {
             using var ctx = _ContextFactory.CreateContext();