From 36fe36d00359ca4d4bb91b72651d70b2bb09e810 Mon Sep 17 00:00:00 2001
From: Nikolai Kochetov <nik-kochetov@yandex-team.ru>
Date: Tue, 20 Feb 2018 16:59:19 +0300
Subject: [PATCH] updated MergeTreePrewhereRangeReader; renamed
 MergeTreePrewhereRangeReader to MergeTreeRangeReader

---
 dbms/src/Storages/MergeTree/MergeTreeBaseBlockInputStream.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/dbms/src/Storages/MergeTree/MergeTreeBaseBlockInputStream.cpp b/dbms/src/Storages/MergeTree/MergeTreeBaseBlockInputStream.cpp
index 8bd4b469593..c2687a4303a 100644
--- a/dbms/src/Storages/MergeTree/MergeTreeBaseBlockInputStream.cpp
+++ b/dbms/src/Storages/MergeTree/MergeTreeBaseBlockInputStream.cpp
@@ -142,6 +142,10 @@ Block MergeTreeBaseBlockInputStream::readFromPart()
 
     auto read_result = task->range_reader.read(rows_to_read, task->mark_ranges);
 
+    /// All rows were filtered. Repeat.
+    if (read_result.block.rows() == 0)
+        read_result.block.clear();
+
     progressImpl({ read_result.block.rows(), read_result.block.bytes() });
 
     if (task->size_predictor)