added readInvalidateQuery

dbms/src/Dictionaries/readInvalidateQuery.cpp

@@ -0,0 +1,56 @@
+#include <Dictionaries/readInvalidateQuery.h>
+#include <DataStreams/IProfilingBlockInputStream.h>
+
+namespace DB
+{
+
+namespace ErrorCodes
+{
+extern const int TOO_MUCH_COLUMNS;
+extern const int TOO_MUCH_ROWS;
+extern const int RECEIVED_EMPTY_DATA;
+}
+
+std::string readInvalidateQuery(IProfilingBlockInputStream & blockInputStream)
+{
+    blockInputStream.readPrefix();
+    std::string response;
+
+    try
+    {
+        Block block = blockInputStream.read();
+        if (!block)
+            throw Exception("Empty response", ErrorCodes::RECEIVED_EMPTY_DATA);
+
+        auto columns = block.columns();
+        if (columns > 1)
+            throw Exception("Expected single column in resultset, got " + std::to_string(columns), ErrorCodes::TOO_MUCH_COLUMNS);
+
+        auto rows = block.rows();
+        if (rows == 0)
+            throw Exception("Expected single row in resultset, got 0", ErrorCodes::RECEIVED_EMPTY_DATA);
+        if (rows > 1)
+            throw Exception("Expected single row in resultset, got at least " + std::to_string(rows), ErrorCodes::TOO_MUCH_ROWS);
+
+        auto column = block.getByPosition(0).column;
+        response = column->getDataAt(0).toString();
+
+        while (block = blockInputStream.read())
+        {
+            if (block.rows() > 0)
+                throw Exception("Expected single row in resultset, got at least " + std::to_string(rows + 1), ErrorCodes::TOO_MUCH_ROWS);
+        }
+    }
+    catch (Exception& exception)
+    {
+        blockInputStream.cancel();
+        blockInputStream.readSuffix();
+        throw;
+    }
+
+    blockInputStream.readSuffix();
+
+    return response;
+}
+
+}

dbms/src/Dictionaries/readInvalidateQuery.h

@@ -0,0 +1,13 @@
+#pragma once
+#include <string>
+
+class IProfilingBlockInputStream;
+
+namespace DB
+{
+
+// Using in MySQLDictionarySource and ODBCDictionarySource after processing invalidate_query
+std::string readInvalidateQuery(IProfilingBlockInputStream & blockInputStream);
+
+
+}