From 75c97ca82aa6de897d41e14267425b67bb0fed1c Mon Sep 17 00:00:00 2001
From: Vitaliy Zakaznikov <vzakaznikov@altinity.com>
Date: Mon, 8 Jun 2020 00:19:23 +0200
Subject: [PATCH] Adding support for PREWHERE in live view tables.

---
 src/Storages/LiveView/StorageBlocks.h         |  5 +++++
 src/Storages/LiveView/StorageLiveView.h       |  1 +
 .../00973_live_view_select_prewhere.reference |  4 ++++
 .../00973_live_view_select_prewhere.sql       | 20 +++++++++++++++++++
 4 files changed, 30 insertions(+)
 create mode 100644 tests/queries/0_stateless/00973_live_view_select_prewhere.reference
 create mode 100644 tests/queries/0_stateless/00973_live_view_select_prewhere.sql

diff --git a/src/Storages/LiveView/StorageBlocks.h b/src/Storages/LiveView/StorageBlocks.h
index a21a9374137..2a9d7766fd7 100644
--- a/src/Storages/LiveView/StorageBlocks.h
+++ b/src/Storages/LiveView/StorageBlocks.h
@@ -26,6 +26,11 @@ public:
         return std::make_shared<StorageBlocks>(table_id, columns, std::move(pipes), to_stage);
     }
     std::string getName() const override { return "Blocks"; }
+    /// It is passed inside the query and solved at its level.
+    bool supportsPrewhere() const override { return true; }
+    bool supportsSampling() const override { return true; }
+    bool supportsFinal() const override { return true; }
+
     QueryProcessingStage::Enum getQueryProcessingStage(const Context &, QueryProcessingStage::Enum /*to_stage*/, const ASTPtr &) const override { return to_stage; }
 
     Pipes read(
diff --git a/src/Storages/LiveView/StorageLiveView.h b/src/Storages/LiveView/StorageLiveView.h
index fe62de224da..85e3d0cee62 100644
--- a/src/Storages/LiveView/StorageLiveView.h
+++ b/src/Storages/LiveView/StorageLiveView.h
@@ -65,6 +65,7 @@ public:
     ASTPtr getInnerBlocksQuery();
 
     /// It is passed inside the query and solved at its level.
+    bool supportsPrewhere() const override { return true; }
     bool supportsSampling() const override { return true; }
     bool supportsFinal() const override { return true; }
 
diff --git a/tests/queries/0_stateless/00973_live_view_select_prewhere.reference b/tests/queries/0_stateless/00973_live_view_select_prewhere.reference
new file mode 100644
index 00000000000..a2a88e78c97
--- /dev/null
+++ b/tests/queries/0_stateless/00973_live_view_select_prewhere.reference
@@ -0,0 +1,4 @@
+5	1
+5	1
+10	2
+10	2
diff --git a/tests/queries/0_stateless/00973_live_view_select_prewhere.sql b/tests/queries/0_stateless/00973_live_view_select_prewhere.sql
new file mode 100644
index 00000000000..e0e2d342f9e
--- /dev/null
+++ b/tests/queries/0_stateless/00973_live_view_select_prewhere.sql
@@ -0,0 +1,20 @@
+SET allow_experimental_live_view = 1;
+
+DROP TABLE IF EXISTS lv;
+DROP TABLE IF EXISTS mt;
+
+CREATE TABLE mt (a Int32) Engine=MergeTree order by tuple();
+CREATE LIVE VIEW lv AS SELECT sum(a) FROM mt PREWHERE a > 1;
+
+INSERT INTO mt VALUES (1),(2),(3);
+
+SELECT *,_version FROM lv;
+SELECT *,_version FROM lv;
+
+INSERT INTO mt VALUES (1),(2),(3);
+
+SELECT *,_version FROM lv;
+SELECT *,_version FROM lv;
+
+DROP TABLE lv;
+DROP TABLE mt;