inital support for parallel load

CMakeLists.txt

@@ -20,5 +20,5 @@ set(SOURCE
 
 add_executable(${PROJECT_NAME} ${SOURCE})
 
-target_link_libraries(${PROJECT_NAME} stdc++ m)
+target_link_libraries(${PROJECT_NAME} stdc++ m pthread)
 

csvreader.cpp

@@ -4,6 +4,7 @@
 #include "csvreader.h"
 #include "parser.h"
 
+#include "threadpoool.h"
 
 namespace usql {
 
@@ -19,13 +20,8 @@ CsvReader::CsvReader(bool skip_hdr, char field_sep, char quote_ch, char line_sep
 
 
 size_t CsvReader::parseCSVFile(const std::string &filename, std::vector<ColDefNode> &cols_def, Table &table) {
+	size_t lines_cnt = 0;
 	size_t row_cnt = 0;
-	std::vector<ColDefNode> cdefs;
-	cdefs.reserve(cols_def.size());
-	for (auto &cd : cols_def) {
-		cdefs.emplace_back(table.get_column_def(cd.name));
-	}
-
 	bool inQuote(false);
 
 	errno = 0;
@@ -37,6 +33,13 @@ size_t CsvReader::parseCSVFile(const std::string &filename, std::vector<ColDefNo
 	size_t len = 0;
 
 	try {
+		// TODO handle it by settings
+		const std::size_t hw_concurrency = 2;	// std::thread::hardware_concurrency();
+		const bool use_threadpool = hw_concurrency > 1;
+
+		thread_pool tp{hw_concurrency};
+		std::mutex row_cnt_mutex;
+		
 		long read_chars;
 		while ((read_chars = getline(&line_str, &len, fp)) != -1) {
 			if (skip_header && !header_skiped) {
@@ -47,8 +50,27 @@ size_t CsvReader::parseCSVFile(const std::string &filename, std::vector<ColDefNo
 				line_str[read_chars - 1] = '\0';
 				--read_chars;
 			}
+			lines_cnt++;
 
+			if (!use_threadpool) {
 				row_cnt += parseCSVString(line_str, cols_def, table);
+			} else {
+				std::string csv_string(line_str);
+				dispatch(tp, std::function<void()>
+							([this, csv_string, &cols_def, &table, &row_cnt, &row_cnt_mutex]() {
+								int parsed = parseCSVString(csv_string, cols_def, table);
+								{
+									std::unique_lock<std::mutex> lock(row_cnt_mutex);
+									row_cnt++;
+								}
+							}
+						));
+			}
+
+		}
+
+		if (use_threadpool) {
+			tp.finish_tasks();
 		}
 
 		fclose(fp);
@@ -67,7 +89,7 @@ size_t CsvReader::parseCSVFile(const std::string &filename, std::vector<ColDefNo
 	return row_cnt;
 }
 
-size_t CsvReader::parseCSVString(const std::string &csvSource, std::vector<ColDefNode> &cols_def, Table& table) {
+size_t CsvReader::parseCSVString(const std::string csvSource, std::vector<ColDefNode> &cols_def, Table& table) {
 	size_t row_cnt = 0;
 	bool inQuote(false);
 	bool newLine(false);

csvreader.h

@@ -26,7 +26,7 @@ namespace usql {
     public:
 	explicit CsvReader(bool skip_hdr = true, char field_sep = ',', char quote_ch = '"', char line_sep = '\r', char line_sep2 = '\n');
 
-	size_t parseCSVString(const std::string &csvSource, std::vector<ColDefNode> &cols_def, Table& table);
+	size_t parseCSVString(const std::string csvSource, std::vector<ColDefNode> &cols_def, Table& table);
 
 	size_t parseCSVFile(const std::string &filename, std::vector<ColDefNode> &cols_def, Table& table);
 

table.cpp

@@ -43,17 +43,15 @@ ColDefNode Table::get_column_def(int col_index) {
 	}
 }
 
-// std::mutex insert_guard;
+std::mutex insert_guard;
 Row& Table::create_empty_row() {
-//	std::unique_lock guard(insert_guard);
+	std::unique_lock guard(insert_guard);
 
 	m_rows.emplace_back(columns_count(), false);
 	return m_rows.back();
 }
 
 void Table::create_row_from_vector(const std::vector<ColDefNode> &colDefs, const std::vector<std::string> &csv_line) {
-//	std::unique_lock guard(insert_guard);
-
 	// prepare empty new_row
 	Row& new_row = create_empty_row();
 

threadpoool.h

@@ -0,0 +1,132 @@
+#include <iostream>
+
+
+#include <thread>
+#include <mutex>
+#include <functional>
+#include <queue>
+#include <condition_variable>
+#include <vector>
+
+class thread_pool {
+ public:
+  thread_pool(std::size_t size) : stop(false), exit_on_empty(false) {
+    for (std::size_t i = 0; i < size; ++i) {
+      workers.emplace_back([this] { spawn(); });
+    }
+  }
+
+  virtual ~thread_pool() {
+    if (!stop) join();
+  }
+
+  // template<class F, class... Args>
+  // void post(F&& f, Args&&... args) {
+  void post(std::function<void()> f) {
+    {
+      std::unique_lock<std::mutex> lock(mutex);
+      tasks.push(f);
+    }
+
+    condition.notify_one();
+  }
+
+  void join() {
+    {
+      std::unique_lock<std::mutex> lock(mutex);
+      stop = true;
+    }
+
+    condition.notify_all();
+
+    for (std::size_t i = 0; i < workers.size(); ++i) {
+      workers[i].join();
+    }
+  }
+
+  void finish_tasks() {
+    {
+      std::unique_lock<std::mutex> lock(mutex);
+      exit_on_empty = true;
+    }
+    
+    while (!tasks.empty()) {
+      condition.notify_all();
+
+      std::unique_lock<std::mutex> lock(mutex);
+      condition_empty.wait(lock, [this]() {
+        return (tasks.empty());
+      });
+    }
+
+    // BLEJU, BLEJU  
+    // while (!tasks.empty()) condition.notify_all();
+    bool op = true;
+  }
+
+ private:
+  void spawn() {
+    std::function<void()> task;
+
+    while (!stop && (!exit_on_empty || !tasks.empty())) {
+      std::unique_lock<std::mutex> lock(mutex);
+      condition.wait(lock, [this]() {
+        return (!tasks.empty()) || (tasks.empty() && stop);
+      });
+
+      if (!tasks.empty()) {
+        task = std::move(tasks.front());
+        tasks.pop();
+        task();
+      }
+    }
+    if (exit_on_empty) {
+      condition_empty.notify_one();
+    }
+  }
+
+public:
+  std::vector<std::thread> workers;
+  std::queue<std::function<void()>> tasks;
+
+  std::mutex mutex;
+  std::condition_variable condition;
+  std::condition_variable condition_empty;
+  bool stop;
+  bool exit_on_empty;
+};
+
+// template<class F, class... Args>
+// inline void dispatch(thread_pool& pool, F&& f, Args&&... args) {
+inline void dispatch(thread_pool& pool, std::function<void()> f) {
+    pool.post(f);
+}
+
+
+
+// int main() {
+//     int cnt = 0;
+    
+//     thread_pool tp{std::thread::hardware_concurrency()};
+//     std::mutex mutex;
+
+//     std::cout << "start" << std::endl;
+
+//     for(int i=0; i<100; i++) {
+//         dispatch(tp, std::function<void()>
+//             ([i, &cnt, &mutex]() {
+//                 std::cout << "test " << i << std::endl;
+//                 {
+//                     std::unique_lock<std::mutex> lock(mutex);
+//                     cnt++;
+//                 }
+//             }
+//         ));
+//     }
+    
+    
+//     std::cout << "end" << std::endl;
+//     tp.join();
+//     std::cout << "cnt:" << cnt << std::endl;
+    
+// }