From ee8b3339a11adc2e76bdc199bd188934fb3fdafe Mon Sep 17 00:00:00 2001
From: nikitamikhaylov <mikhaylovnikitka@gmail.com>
Date: Fri, 6 Nov 2020 21:28:59 +0300
Subject: [PATCH 1/2] done

---
 src/Interpreters/Context.cpp | 17 +++++++++++++++--
 src/Interpreters/Context.h   |  2 ++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/Interpreters/Context.cpp b/src/Interpreters/Context.cpp
index 94ebd397f51..6275e37953b 100644
--- a/src/Interpreters/Context.cpp
+++ b/src/Interpreters/Context.cpp
@@ -1465,11 +1465,16 @@ BackgroundSchedulePool & Context::getDistributedSchedulePool()
     return *shared->distributed_schedule_pool;
 }
 
+bool Context::hasDistributedDDL() const 
+{
+    return getConfigRef().has("distributed_ddl");
+}
+
 void Context::setDDLWorker(std::unique_ptr<DDLWorker> ddl_worker)
 {
     auto lock = getLock();
     if (shared->ddl_worker)
-        throw Exception("DDL background thread has already been initialized.", ErrorCodes::LOGICAL_ERROR);
+        throw Exception("DDL background thread has already been initialized", ErrorCodes::LOGICAL_ERROR);
     shared->ddl_worker = std::move(ddl_worker);
 }
 
@@ -1477,7 +1482,15 @@ DDLWorker & Context::getDDLWorker() const
 {
     auto lock = getLock();
     if (!shared->ddl_worker)
-        throw Exception("DDL background thread is not initialized.", ErrorCodes::NO_ELEMENTS_IN_CONFIG);
+    {
+        if (!hasZooKeeper())
+            throw Exception("There is no Zookeeper configuration in server config", ErrorCodes::NO_ELEMENTS_IN_CONFIG);
+
+        if (!hasDistributedDDL())
+            throw Exception("There is no DistributedDDL configuration in server config", ErrorCodes::NO_ELEMENTS_IN_CONFIG);
+
+        throw Exception("DDL background thread is not initialized", ErrorCodes::NO_ELEMENTS_IN_CONFIG);
+    }
     return *shared->ddl_worker;
 }
 
diff --git a/src/Interpreters/Context.h b/src/Interpreters/Context.h
index a2b61b29514..de7f7488a7c 100644
--- a/src/Interpreters/Context.h
+++ b/src/Interpreters/Context.h
@@ -523,6 +523,8 @@ public:
     BackgroundSchedulePool & getSchedulePool();
     BackgroundSchedulePool & getDistributedSchedulePool();
 
+    /// Has distributed_ddl configuration or not. 
+    bool hasDistributedDDL() const;
     void setDDLWorker(std::unique_ptr<DDLWorker> ddl_worker);
     DDLWorker & getDDLWorker() const;
 

From 6f4e5bcaac2916b94c04f3333accb1ad5b060a02 Mon Sep 17 00:00:00 2001
From: nikitamikhaylov <mikhaylovnikitka@gmail.com>
Date: Thu, 12 Nov 2020 23:11:04 +0300
Subject: [PATCH 2/2] style

---
 src/Interpreters/Context.cpp | 2 +-
 src/Interpreters/Context.h   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Interpreters/Context.cpp b/src/Interpreters/Context.cpp
index 6275e37953b..54ee7713e95 100644
--- a/src/Interpreters/Context.cpp
+++ b/src/Interpreters/Context.cpp
@@ -1465,7 +1465,7 @@ BackgroundSchedulePool & Context::getDistributedSchedulePool()
     return *shared->distributed_schedule_pool;
 }
 
-bool Context::hasDistributedDDL() const 
+bool Context::hasDistributedDDL() const
 {
     return getConfigRef().has("distributed_ddl");
 }
diff --git a/src/Interpreters/Context.h b/src/Interpreters/Context.h
index de7f7488a7c..02a57b5d966 100644
--- a/src/Interpreters/Context.h
+++ b/src/Interpreters/Context.h
@@ -523,7 +523,7 @@ public:
     BackgroundSchedulePool & getSchedulePool();
     BackgroundSchedulePool & getDistributedSchedulePool();
 
-    /// Has distributed_ddl configuration or not. 
+    /// Has distributed_ddl configuration or not.
     bool hasDistributedDDL() const;
     void setDDLWorker(std::unique_ptr<DDLWorker> ddl_worker);
     DDLWorker & getDDLWorker() const;