tarantool: add index for cleansing fiber

hitbox-tarantool/src/init.lua

@@ -1,35 +1,51 @@
 local fiber = require("fiber")
 local log = require("log")
 
+local SCAN_INTERVAL = 0.1
+local MAX_TUPLES_FOR_DELETE = 1000
+
 box.cfg({})
 
 local space_name = ...
 
 box.schema.space.create(space_name, { if_not_exists = true })
 box.space[space_name]:create_index("primary", {
-	type = 'HASH',
+	type = "HASH",
 	parts = { { 1, "string" } },
 	if_not_exists = true,
 })
+box.space[space_name]:create_index("by_ttl", {
+	parts = { { 2, "integer" } },
+	if_not_exists = true,
+})
 
 if not _G.__hitbox_cache_fiber then
 	_G.__hitbox_cache_fiber = fiber.create(function()
 		fiber.name("hitbox_cache_fiber")
 		while true do
+			box.ctl.wait_rw()
+
 			local ok, err = pcall(function()
-				for _, t in box.space[space_name]:pairs() do
-					if t[2] <= fiber.time() then
+				local for_del = box.space[space_name].index.by_ttl
+					:pairs({ math.floor(fiber.time()) }, { iterator = "LE" })
+					:take(MAX_TUPLES_FOR_DELETE)
+					:totable()
+
+				box.atomic(function()
+					for _, t in pairs(for_del) do
 						box.space[space_name]:delete(t[1])
 					end
-				end
+				end)
+
+				return true
 			end)
 
 			if not ok then
 				log.error(err)
 			end
 
 			fiber.testcancel()
-			fiber.sleep(1)
+			fiber.sleep(SCAN_INTERVAL)
 		end
 	end)
 end