From 7041e2807794b7247cc55f5d17428e76aeffc480 Mon Sep 17 00:00:00 2001
From: CurtizJ <pad11rus@gmail.com>
Date: Fri, 14 Feb 2020 00:16:40 +0300
Subject: [PATCH] fix segfault in MergeTreeRangeReader

---
 dbms/src/Storages/MergeTree/MergeTreeRangeReader.cpp  |  2 +-
 .../01079_new_range_reader_segfault.reference         |  1 +
 .../0_stateless/01079_new_range_reader_segfault.sql   | 11 +++++++++++
 3 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 dbms/tests/queries/0_stateless/01079_new_range_reader_segfault.reference
 create mode 100644 dbms/tests/queries/0_stateless/01079_new_range_reader_segfault.sql

diff --git a/dbms/src/Storages/MergeTree/MergeTreeRangeReader.cpp b/dbms/src/Storages/MergeTree/MergeTreeRangeReader.cpp
index 56e5cfdb3d2..cd458669d81 100644
--- a/dbms/src/Storages/MergeTree/MergeTreeRangeReader.cpp
+++ b/dbms/src/Storages/MergeTree/MergeTreeRangeReader.cpp
@@ -333,8 +333,8 @@ void MergeTreeRangeReader::ReadResult::optimize()
             filter_holder_original = std::move(filter_holder);
             filter = new_filter.get();
             filter_holder = std::move(new_filter);
+            need_filter = true;
         }
-        need_filter = true;
     }
     /// Another guess, if it's worth filtering at PREWHERE
     else if (countBytesInResultFilter(filter->getData()) < 0.6 * filter->size())
diff --git a/dbms/tests/queries/0_stateless/01079_new_range_reader_segfault.reference b/dbms/tests/queries/0_stateless/01079_new_range_reader_segfault.reference
new file mode 100644
index 00000000000..257cc5642cb
--- /dev/null
+++ b/dbms/tests/queries/0_stateless/01079_new_range_reader_segfault.reference
@@ -0,0 +1 @@
+foo
diff --git a/dbms/tests/queries/0_stateless/01079_new_range_reader_segfault.sql b/dbms/tests/queries/0_stateless/01079_new_range_reader_segfault.sql
new file mode 100644
index 00000000000..35de0d0b1df
--- /dev/null
+++ b/dbms/tests/queries/0_stateless/01079_new_range_reader_segfault.sql
@@ -0,0 +1,11 @@
+drop table if exists t;
+
+create table t (a Int) engine = MergeTree order by a;
+
+-- some magic to satisfy conditions to run optimizations in MergeTreeRangeReader
+insert into t select number < 10 ? 0 : 1 from numbers(50);
+alter table t add column s String default 'foo';
+
+select s from t prewhere a != 1 where rand() % 2 = 0 limit 1;
+
+drop table t;