Limit insertion to 100 records per query, but this is still suboptimal.

src/dbbackend.cpp

@@ -23,6 +23,7 @@
 
 namespace din {
 	namespace {
+		const std::size_t g_batch_size = 100;
 	} //unnamed namespace
 
 	void write_to_db (const std::vector<FileRecordData>& parData) {
@@ -30,15 +31,18 @@ namespace din {
 			return;
 		}
 
-		std::ostringstream query;
-		query << "BEGIN;\n";
-		query << "INSERT INTO \"Files\" (path, hash, level, group_id, is_directory, is_symlink, size) VALUES ";
-
 		pq::Connection conn("michele", "password", "dindexer", "100.200.100.200", 5432);
 		conn.connect();
 
+		conn.query_void("BEGIN;");
+		//TODO: use COPY instead of INSERT INTO
+		for (std::size_t z = 0; z < parData.size(); z += g_batch_size) {
+			std::ostringstream query;
+			query << "INSERT INTO \"Files\" (path, hash, level, group_id, is_directory, is_symlink, size) VALUES ";
+
 			const char* comma = "";
-		for (const auto& itm : parData) {
+			for (auto i = z; i < std::min(z + g_batch_size, parData.size()); ++i) {
+				const auto& itm = parData[i];
 				query << comma;
 				query << '(' << conn.escape_literal(itm.path) << ",'" << itm.hash << "',"
 					<< itm.level << ','
@@ -48,8 +52,10 @@ namespace din {
 				comma = ",";
 			}
 			query << ';';
-		query << "\nCOMMIT;";
+			//query << "\nCOMMIT;";
 
 			conn.query_void(query.str());
 		}
+		conn.query_void("COMMIT;");
+	}
 } //namespace din