diff --git a/colddb.lua b/colddb.lua
index 495f2a6..d842d3a 100644
--- a/colddb.lua
+++ b/colddb.lua
@@ -34,6 +34,10 @@ function colddb.get_db(directory)
 		indexes = false,
 		add_to_mem_pool = true,
 	}
+	-- make tables weak so the garbage-collector will remove unused data
+	setmetatable(db.tags, {__mode = "kv"})
+	setmetatable(db.mem_pool, {__mode = "kv"})
+	setmetatable(db.indexes_pool, {__mode = "kv"})
 	return db
 end
 
@@ -269,7 +273,7 @@ function colddb.create_index_table(db,tag_name)
 	if f then
 		f:seek("set")
 		f:write("0")
-		db.indexes_pool[string.format("%s%s",t,name)] = {file = f,needs_flushing = false,deleted_items = {},iterating = false,inuse = false}
+		db.indexes_pool[string.format("%s%s",t,name)] = {file = f,needs_flushing = false,deleted_items = {},iterating = false}
 		return true
 	end
 	return false
@@ -295,7 +299,7 @@ function colddb.open_index_table(db,tag_name)
 		end
 		local f = io.open(p, "r+")
 		if f then
-			db.indexes_pool[cs] = {file = f,needs_flushing = false,deleted_items = {},iterating = false,inuse = true}
+			db.indexes_pool[cs] = {file = f,needs_flushing = false,deleted_items = {},iterating = false}
 			return f
 		end
 		return nil
@@ -320,7 +324,6 @@ function colddb.append_index_table(db,key,tag_name)
 			fl:flush()
 		end
 		db.indexes_pool[cs].needs_flushing = true
-		db.indexes_pool[cs].inuse = true
 		fl:seek("end")
 		fl:write(string.format("\n%s",key))
 		fl:seek("set")
@@ -334,7 +337,6 @@ function colddb.append_index_table(db,key,tag_name)
 			fl:flush()
 		end
 		db.indexes_pool[cs].needs_flushing = true
-		db.indexes_pool[cs].inuse = true
 		local c = 0
 		for i in pairs(key) do
 			fl:seek("end")
@@ -367,7 +369,6 @@ function colddb.get_count(db,tag_name)
 		end
 		fl:seek("set")
 		local count = tonumber(fl:read("*l"))
-		db.indexes_pool[cs].inuse = true
 		return count
 	end
 	return nil
@@ -375,7 +376,6 @@ end
 
 local function iterate(db,func_on_iterate,end_func,cycles_per_tick,count,cs,args)
 	local f = db.indexes_pool[cs]
-	f.inuse = true
 	local fl = f.file
 	for i=1,cycles_per_tick do
 		if count < 1 then
@@ -394,6 +394,11 @@ local function iterate(db,func_on_iterate,end_func,cycles_per_tick,count,cs,args
 		end
 		if db.iterate_queue[cs] and db.iterate_queue[cs][1] then
 			local copy = db.iterate_queue[cs][1]
+			f = db.indexes_pool[cs]
+			if not f or not f.file then
+				colddb.open_index_table(db,copy.tag_name)
+				f = db.indexes_pool[cs]
+			end
 			if copy.begin_func then
 				local a = copy.begin_func(copy.args)
 				if a and type(a) == "table" then
@@ -425,8 +430,6 @@ function colddb.iterate_index_table(db,begin_func,func_on_iterate,end_func,cycle
 		f = db.indexes_pool[cs]
 	end
 	if f and f.file and db.indexes_pool[cs].iterating == false then
-		-- set inuse and iterating to true
-		db.indexes_pool[cs].inuse = true
 		db.indexes_pool[cs].iterating = true
 		local fl = f.file
 		if f.needs_flushing == true then
@@ -469,42 +472,6 @@ function colddb.iterate_index_table(db,begin_func,func_on_iterate,end_func,cycle
 	end
 end
 
-local function check_use(db,name,tag_name,d)
-	if not d then
-		d = 0
-	end
-	local delay = 30 + d
-	local t = ""
-	if tag_name then
-		t = colddb.get_tag(db,tag_name)
-	end
-	local cs = string.format("%s%s",t,name)
-	if not db.mem_pool or not db.mem_pool[cs] then
-		return false
-	end
-	if db.mem_pool[cs].inuse == false then
-		if db.mem_pool[cs].indexes == true then
-			local cs2 = string.format("%s%s",t,"æIndex_table")
-			local fs = db.indexes_pool[cs2]
-				if fs and fs.file then
-					if fs.inuse == true or fs.iterating == true then
-						db.indexes_pool[cs2].inuse = false
-						minetest.after(delay,check_use,name,tag_name,delay,d)
-						return false
-					else
-						fs.file:close()
-						db.indexes_pool[cs2] = nil
-					end
-				end
-		end
-		db.mem_pool[cs] = nil
-	else
-		db.mem_pool[cs].inuse = false
-		minetest.after(delay,check_use,name,tag_name,delay,d)
-		return false
-	end
-end
-
 local function load_into_mem(db,name,_table,tag_name)
 	if db.add_to_mem_pool then
 		local t = ""
@@ -513,14 +480,10 @@ local function load_into_mem(db,name,_table,tag_name)
 		end
 		local cs = string.format("%s%s",t,name)
 		if not db.mem_pool[cs] then
-			db.mem_pool[cs] = {mem = {},inuse = false,check_timer = false,indexes = db.indexes}
-		end
-		db.mem_pool[cs].mem = _table
-		if not db.mem_pool[cs].check_timer then
-			db.mem_pool[cs].inuse = false
+			db.mem_pool[cs] = {mem = _table,indexes = db.indexes}
+		else
+			db.mem_pool[cs].mem = _table
 			db.mem_pool[cs].indexes = db.indexes
-			db.mem_pool[cs].check_timer = true
-			minetest.after(30,check_use,name,tag_name,30,0)
 		end
 	end
 end
@@ -539,9 +502,7 @@ function colddb.set(db,name,_table,tag_name)
 		minetest.after(0,function(db,name,tag_name)colddb.append_index_table(db,name,tag_name)end,db,name,tag_name)
 	end
 	minetest.after(1,function(db,name, _table,tag_name)colddb.save_table(db,name, _table,tag_name)end,db,name, _table,tag_name)
-	local cs = string.format("%s%s",t,name)
-	if db.add_to_mem_pool and not (db.mem_pool or db.mem_pool[cs]) then
-		db.mem_pool[cs] = {mem = {},inuse = false,check_timer = false,indexes = db.indexes}
+	if db.add_to_mem_pool then
 		load_into_mem(db,name,_table,tag_name)
 	end
 end
@@ -560,10 +521,8 @@ function colddb.set_key(db,name,tag_name)
 		minetest.after(0,function(db,name,tag_name)colddb.append_index_table(db,name,tag_name)end,db,name,tag_name)
 	end
 	minetest.after(1,function(db,name, tag_name)colddb.save_key(db,name, tag_name)end,db,name, tag_name)
-	local cs = string.format("%s%s",t,name)
-	if db.add_to_mem_pool and not (db.mem_pool or db.mem_pool[cs]) then
-		db.mem_pool[cs] = {mem = {},inuse = false,check_timer = false,indexes = db.indexes}
-		load_into_mem(db,name,_table,tag_name)
+	if db.add_to_mem_pool then
+		load_into_mem(db,name,"",tag_name)
 	end
 end
 
@@ -575,7 +534,6 @@ function colddb.get(db,name,tag_name)
 	local cs = string.format("%s%s",t,name)
 	local pm = db.mem_pool[cs]
 	if pm then
-		db.mem_pool[cs].inuse = true
 		return pm.mem
 	else
 		local _table = colddb.load_table(db,name,tag_name)
@@ -595,7 +553,6 @@ function colddb.get_key(db,name,tag_name)
 	local cs = string.format("%s%s",t,name)
 	local pm = db.mem_pool[cs]
 	if pm then
-		db.mem_pool[cs].inuse = true
 		return true
 	else
 		local bool = colddb.load_key(db,name,tag_name)
@@ -613,7 +570,7 @@ function colddb.remove(db,name,tag_name)
 		t = colddb.get_tag(db,tag_name)
 	end
 	local cs = string.format("%s%s",t,name)
-	if db.mem_pool and db.mem_pool[cs] then
+	if db.mem_pool[cs] then
 		db.mem_pool[cs] = nil
 	end
 	if db.indexes and colddb.file_Exists(db,"æIndex_table",tag_name) then