From 2eb2e4cf41909dc82ccf5cd30c02f81941e40e36 Mon Sep 17 00:00:00 2001
From: Alexander Kazakov <Akazz@users.noreply.github.com>
Date: Sun, 12 Apr 2020 20:17:41 +0300
Subject: [PATCH] Added proper nullptr check

---
 src/Storages/System/StorageSystemTables.cpp | 23 +++++++++++++--------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/src/Storages/System/StorageSystemTables.cpp b/src/Storages/System/StorageSystemTables.cpp
index f4ce4a8b71..81ff6a03e1 100644
--- a/src/Storages/System/StorageSystemTables.cpp
+++ b/src/Storages/System/StorageSystemTables.cpp
@@ -239,20 +239,25 @@ protected:
                 StoragePtr table = nullptr;
                 TableStructureReadLockHolder lock;
 
-                try
+                if (need_lock_structure)
                 {
-                    if (need_lock_structure)
+                    table = tables_it->table();
+                    if (table == nullptr)
+                    {
+                        // Table might have just been removed or detached for Lazy engine (see DatabaseLazy::tryGetTable())
+                        continue;
+                    }
+                    try
                     {
-                        table = tables_it->table();
                         lock = table->lockStructureForShare(
                                 false, context.getCurrentQueryId(), context.getSettingsRef().lock_acquire_timeout);
                     }
-                }
-                catch (const Exception & e)
-                {
-                    if (e.code() == ErrorCodes::TABLE_IS_DROPPED)
-                        continue;
-                    throw;
+                    catch (const Exception & e)
+                    {
+                        if (e.code() == ErrorCodes::TABLE_IS_DROPPED)
+                            continue;
+                        throw;
+                    }
                 }
 
                 ++rows_count;
-- 
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