Sending progress in HTTP headers (continued) [#CLICKHOUSE-32].

dbms/include/DB/IO/WriteBufferFromHTTPServerResponse.h

@@ -14,6 +14,7 @@
 #include <DB/IO/ZlibDeflatingWriteBuffer.h>
 #include <DB/IO/HTTPCommon.h>
 #include <DB/Common/NetException.h>
+#include <DB/Common/Stopwatch.h>
 #include <DB/Core/Progress.h>
 
 
@@ -56,6 +57,8 @@ private:
 	bool body_started_sending = false;	/// If true, you could not add any headers.
 
 	Progress accumulated_progress;
+	size_t send_progress_interval_ms = 100;
+	Stopwatch progress_watch;
 
 	std::mutex mutex;	/// progress callback could be called from different threads.
 
@@ -143,11 +146,15 @@ public:
 		if (body_started_sending)
 			return;
 
+		accumulated_progress.incrementPiecewiseAtomically(progress);
+
+		if (progress_watch.elapsed() >= send_progress_interval_ms * 1000000)
+		{
+			progress_watch.restart();
+
 			/// Send all common headers before our special progress headers.
 			startSendHeaders();
 
-		accumulated_progress.incrementPiecewiseAtomically(progress);
-
 			std::string progress_string;
 			{
 				WriteBufferFromString progress_string_writer(progress_string);
@@ -156,6 +163,7 @@ public:
 
 			*response_header_ostr << "X-ClickHouse-Progress: " << progress_string << "\r\n" << std::flush;
 		}
+	}
 
 	/// Send at least HTTP headers if no data has been sent yet.
 	/// Use after the data has possibly been sent and no error happened (and thus you do not plan
@@ -187,6 +195,13 @@ public:
 		add_cors_header = enable_cors;
 	}
 
+	/// Don't send HTTP headers with progress more frequently.
+	void setSendProgressInterval(size_t send_progress_interval_ms_)
+	{
+		send_progress_interval_ms = send_progress_interval_ms_;
+	}
+
+
 	~WriteBufferFromHTTPServerResponse()
 	{
 		if (!offset())

dbms/include/DB/Interpreters/Settings.h

@@ -237,7 +237,10 @@ struct Settings
 	M(SettingUInt64, output_format_pretty_max_rows, 10000) \
 	\
 	/** Use client timezone for interpreting DateTime string values, instead of adopting server timezone. */ \
-	M(SettingBool, use_client_time_zone, false)
+	M(SettingBool, use_client_time_zone, false) \
+	\
+	/** Do not send HTTP headers X-ClickHouse-Progress more frequently than at each specified interval. */ \
+	M(SettingUInt64, http_headers_progress_interval_ms, 100) \
 
 	/// Всевозможные ограничения на выполнение запроса.
 	Limits limits;

dbms/src/Server/HTTPHandler.cpp

@@ -229,6 +229,8 @@ void HTTPHandler::processQuery(
 	if (client_supports_http_compression)
 		used_output.out->setCompressionLevel(context.getSettingsRef().http_zlib_compression_level);
 
+	used_output.out->setSendProgressInterval(context.getSettingsRef().http_headers_progress_interval_ms);
+
 	/// If 'http_native_compression_disable_checksumming_on_decompress' setting is turned on,
 	/// checksums of client data compressed with internal algorithm are not checked.
 	if (in_post_compressed && context.getSettingsRef().http_native_compression_disable_checksumming_on_decompress)