diff --git a/src/backends/redis/CMakeLists.txt b/src/backends/redis/CMakeLists.txt
index 19f75d5..19f7f05 100644
--- a/src/backends/redis/CMakeLists.txt
+++ b/src/backends/redis/CMakeLists.txt
@@ -51,8 +51,7 @@ configure_file(
 	${CMAKE_CURRENT_BINARY_DIR}/redisConfig.h
 )
 set(LUA_SCRIPTS
-	"${CMAKE_SOURCE_DIR}/lib/ohm-scripts/save.lua"
-	"${CMAKE_SOURCE_DIR}/lib/ohm-scripts/delete.lua"
+	tag_if_in_set.lua
 )
 
 install(TARGETS ${PROJECT_NAME}
diff --git a/src/backends/redis/backend_redis.cpp b/src/backends/redis/backend_redis.cpp
index 990a6e1..3bd8543 100644
--- a/src/backends/redis/backend_redis.cpp
+++ b/src/backends/redis/backend_redis.cpp
@@ -27,6 +27,8 @@
 #include <array>
 #include <cstdint>
 #include <boost/range/empty.hpp>
+#include <fstream>
+#include <sstream>
 
 namespace dindb {
 	namespace {
@@ -94,6 +96,23 @@ namespace dindb {
 			}
 			return retval;
 		}
+
+		std::string read_script (const dincore::SearchPaths& parSearch, const char* parName) {
+			const auto full_path = parSearch.first_hit(boost::string_ref(parName));
+			if (full_path.empty()) {
+				const std::string msg = std::string("Unable to locate and load Lua script \"") + parName + "\" from any of the given search paths";
+				throw std::runtime_error(msg);
+			}
+
+			std::ifstream script(full_path);
+			std::string retval;
+			script.seekg(0, std::ios::end);
+			retval.reserve(script.tellg());
+			script.seekg(0, std::ios::beg);
+			retval.assign(std::istreambuf_iterator<char>(script), std::istreambuf_iterator<char>());
+
+			return retval;
+		}
 	} //unnamed namespace
 } //namespace dindb
 
@@ -140,6 +159,7 @@ namespace YAML {
 namespace dindb {
 	BackendRedis::BackendRedis(std::string&& parAddress, uint16_t parPort, uint16_t parDatabase, bool parConnect, dincore::SearchPaths&& parLuaPaths) :
 		m_redis(std::move(parAddress), parPort),
+		m_tag_if_in_set(),
 		m_lua_script_paths(std::move(parLuaPaths)),
 		m_database(parDatabase)
 	{
@@ -166,6 +186,8 @@ namespace dindb {
 			oss << "Error connecting to Redis: " << m_redis.connection_error();
 			throw std::runtime_error(oss.str());
 		}
+
+		m_tag_if_in_set = m_redis.make_script(read_script(m_lua_script_paths, "tag_if_in_set.lua"));
 	}
 
 	void BackendRedis::disconnect() {
@@ -173,6 +195,21 @@ namespace dindb {
 	}
 
 	void BackendRedis::tag_files (const std::vector<FileIDType>& parFiles, const std::vector<boost::string_ref>& parTags, GroupIDType parSet) {
+		using dinhelp::lexical_cast;
+
+		auto batch = m_redis.make_batch();
+		const std::string set_key = (parSet != InvalidGroupID ? PROGRAM_NAME ":set:" + lexical_cast<std::string>(parSet) : "");
+		for (const auto file_id : parFiles) {
+			for (const auto &tag : parTags) {
+				std::ostringstream oss;
+				oss << PROGRAM_NAME ":tag:" << tag;
+				const std::string tag_key = oss.str();
+				const std::string file_key = PROGRAM_NAME ":file:" + lexical_cast<std::string>(file_id);
+				m_tag_if_in_set.run(batch, std::make_tuple(tag_key, file_key), std::make_tuple(set_key));
+			}
+		}
+
+		batch.throw_if_failed();
 	}
 
 	void BackendRedis::tag_files (const std::vector<std::string>& parRegexes, const std::vector<boost::string_ref>& parTags, GroupIDType parSet) {
diff --git a/src/backends/redis/backend_redis.hpp b/src/backends/redis/backend_redis.hpp
index d7ced97..08fb6cc 100644
--- a/src/backends/redis/backend_redis.hpp
+++ b/src/backends/redis/backend_redis.hpp
@@ -20,6 +20,7 @@
 
 #include "backends/db_backend.hpp"
 #include "command.hpp"
+#include "script.hpp"
 #include "dindexer-core/searchpaths.hpp"
 #include <string>
 #include <cstdint>
@@ -58,6 +59,7 @@ namespace dindb {
 
 	private:
 		redis::Command m_redis;
+		redis::Script m_tag_if_in_set;
 		dincore::SearchPaths m_lua_script_paths;
 		uint16_t m_database;
 	};
diff --git a/src/backends/redis/tag_if_in_set.lua b/src/backends/redis/tag_if_in_set.lua
new file mode 100644
index 0000000..6c9ec12
--- /dev/null
+++ b/src/backends/redis/tag_if_in_set.lua
@@ -0,0 +1,30 @@
+-- Copyright 2015, 2016, Michele Santullo
+-- This file is part of "dindexer".
+--
+-- "dindexer" is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- "dindexer" is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with "dindexer".  If not, see <http://www.gnu.org/licenses/>.
+
+local tag_key = KEYS[1]
+local file_key = KEYS[2]
+local group_key = ARGV[1]
+
+if group_key == "" then
+	return redis.call("SADD", tag_key, file_key)
+else
+	local found_group_key = redis.call("HGET", file_key, "group_id")
+	if found_group_key == group_key then
+		return redis.call("SADD", tag_key, file_key)
+	else
+		return nil
+	end
+end