add interpretation of PREWHERE in StorageBuffer::read

dbms/src/Storages/StorageBuffer.cpp

@@ -25,6 +25,8 @@
 #include <Poco/Ext/ThreadNumber.h>
 
 #include <ext/range.h>
+#include <DataStreams/FilterBlockInputStream.h>
+#include <DataStreams/ExpressionBlockInputStream.h>
 
 
 namespace ProfileEvents
@@ -223,6 +225,20 @@ BlockInputStreams StorageBuffer::read(
         for (auto & stream : streams_from_buffers)
             stream = InterpreterSelectQuery(query_info.query, context, stream, processed_stage).execute().in;
 
+    if (query_info.prewhere_info)
+    {
+        for (auto & stream : streams_from_buffers)
+            stream = std::make_shared<FilterBlockInputStream>(stream, query_info.prewhere_info->prewhere_actions,
+                    query_info.prewhere_info->prewhere_column_name, query_info.prewhere_info->remove_prewhere_column);
+
+        if (query_info.prewhere_info->alias_actions)
+        {
+            for (auto & stream : streams_from_buffers)
+                stream = std::make_shared<ExpressionBlockInputStream>(stream, query_info.prewhere_info->alias_actions);
+
+        }
+    }
+
     streams_from_dst.insert(streams_from_dst.end(), streams_from_buffers.begin(), streams_from_buffers.end());
     return streams_from_dst;
 }

dbms/tests/queries/0_stateless/00910_buffer_prewhere.reference

-1
\ No newline at end of file
+1

dbms/tests/queries/0_stateless/00910_buffer_prewhere.sql

@@ -2,5 +2,6 @@ DROP DATABASE IF EXISTS test_buffer;
 CREATE DATABASE test_buffer;
 CREATE TABLE test_buffer.mt (uid UInt64, ts DateTime, val Float64) ENGINE = MergeTree PARTITION BY toDate(ts) ORDER BY (uid, ts);
 CREATE TABLE test_buffer.buf as test_buffer.mt ENGINE = Buffer(test_buffer, mt, 2, 10, 60, 10000, 100000, 1000000, 10000000);
-INSERT INTO test_buffer.buf VALUES (1, '2019-03-01 10:00:00', 0.5), (2, '2019-03-02 10:00:00', 0.15), (1, '2019-03-03 10:00:00', 0.25)
-SELECT count() from test_buffer.buf prewhere ts > toDateTime('2019-03-01 12:00:00') and ts < toDateTime('2019-03-02 12:00:00')
\ No newline at end of file
+INSERT INTO test_buffer.buf VALUES (1, '2019-03-01 10:00:00', 0.5), (2, '2019-03-02 10:00:00', 0.15), (1, '2019-03-03 10:00:00', 0.25);
+SELECT count() from test_buffer.buf prewhere ts > toDateTime('2019-03-01 12:00:00') and ts < toDateTime('2019-03-02 12:00:00');
+DROP DATABASE test_buffer;