From b22b65dd299f77f882e8c98f7342b03671bd678f Mon Sep 17 00:00:00 2001
From: Azat Khuzhin <a3at.mail@gmail.com>
Date: Sat, 21 Sep 2019 02:22:25 +0300
Subject: [PATCH] Avoid SIGSEGV on batch send failure (file with index XX is
 absent)

In case of the following error:
  Failed to send batch: file with index 23742 is absent

NULL dereference will occur for the "remote".
---
 dbms/src/Storages/Distributed/DirectoryMonitor.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/dbms/src/Storages/Distributed/DirectoryMonitor.cpp b/dbms/src/Storages/Distributed/DirectoryMonitor.cpp
index df19d76bbb34..183897c75745 100644
--- a/dbms/src/Storages/Distributed/DirectoryMonitor.cpp
+++ b/dbms/src/Storages/Distributed/DirectoryMonitor.cpp
@@ -392,7 +392,8 @@ struct StorageDistributedDirectoryMonitor::Batch
                 remote->writePrepared(in);
             }
 
-            remote->writeSuffix();
+            if (remote)
+                remote->writeSuffix();
         }
         catch (const Exception & e)
         {