diff --git a/lua/frecency/config.lua b/lua/frecency/config.lua
index e6e41d9..df59769 100644
--- a/lua/frecency/config.lua
+++ b/lua/frecency/config.lua
@@ -4,6 +4,7 @@ local os_util = require "frecency.os_util"
 ---@class FrecencyOpts
 ---@field recency_values? { age: integer, value: integer }[] default: see lua/frecency/config.lua
 ---@field auto_validate? boolean default: true
+---@field bootstrap? boolean default: true
 ---@field db_root? string default: vim.fn.stdpath "state"
 ---@field db_safe_mode? boolean default: true
 ---@field db_validate_threshold? integer default: 10
@@ -33,6 +34,7 @@ local Config = {}
 ---@class FrecencyRawConfig
 ---@field recency_values { age: integer, value: integer }[] default: see lua/frecency/config.lua
 ---@field auto_validate boolean default: true
+---@field bootstrap boolean default: true
 ---@field db_root string default: vim.fn.stdpath "state"
 ---@field db_safe_mode boolean default: true
 ---@field db_validate_threshold integer default: 10
@@ -59,6 +61,7 @@ Config.new = function()
   local keys = {
     recency_values = true,
     auto_validate = true,
+    bootstrap = true,
     db_root = true,
     db_safe_mode = true,
     db_validate_threshold = true,
@@ -98,6 +101,7 @@ end
 ---@type FrecencyRawConfig
 Config.default_values = {
   auto_validate = true,
+  bootstrap = true,
   db_root = vim.fn.stdpath "state" --[[@as string]],
   db_safe_mode = true,
   db_validate_threshold = 10,
@@ -158,6 +162,7 @@ Config.setup = function(ext_config)
   vim.validate {
     recency_values = { opts.recency_values, "t" },
     auto_validate = { opts.auto_validate, "b" },
+    bootstrap = { opts.bootstrap, "b" },
     db_root = { opts.db_root, "s" },
     db_safe_mode = { opts.db_safe_mode, "b" },
     db_validate_threshold = { opts.db_validate_threshold, "n" },
diff --git a/lua/frecency/database.lua b/lua/frecency/database.lua
index f9d2916..233d523 100644
--- a/lua/frecency/database.lua
+++ b/lua/frecency/database.lua
@@ -22,6 +22,7 @@ local Path = lazy_require "plenary.path" --[[@as FrecencyPlenaryPath]]
 ---@field private _file_lock FrecencyFileLock
 ---@field private file_lock_rx async fun(): ...
 ---@field private file_lock_tx fun(...): nil
+---@field private is_started boolean
 ---@field private tbl FrecencyDatabaseTable
 ---@field private version FrecencyDatabaseVersion
 ---@field private watcher_rx FrecencyPlenaryAsyncControlChannelRx
@@ -36,6 +37,7 @@ Database.new = function()
   return setmetatable({
     file_lock_rx = file_lock_rx,
     file_lock_tx = file_lock_tx,
+    is_started = false,
     tbl = Table.new(version),
     version = version,
     watcher_rx = watcher_rx,
@@ -74,6 +76,11 @@ end
 ---@async
 ---@return nil
 function Database:start()
+  timer.track "Database:start() start"
+  if self.is_started then
+    return
+  end
+  self.is_started = true
   local target = self:filename()
   self.file_lock_tx(FileLock.new(target))
   self.watcher_tx.send "load"
@@ -94,6 +101,7 @@ function Database:start()
       log.debug("DB coroutine end:", mode)
     end
   end)()
+  timer.track "Database:start() finish"
 end
 
 ---@async
diff --git a/lua/frecency/init.lua b/lua/frecency/init.lua
index 5db13ac..f6b8e38 100644
--- a/lua/frecency/init.lua
+++ b/lua/frecency/init.lua
@@ -1,7 +1,11 @@
+---@type FrecencyDatabase?
+local database
+
 ---This object is intended to be used as a singleton, and is lazily loaded.
 ---When methods are called at the first time, it calls the constructor and
 ---setup() to be initialized.
 ---@class FrecencyInstance
+---@field bootstrap async fun(): nil
 ---@field complete fun(findstart: 1|0, base: string): integer|''|string[]
 ---@field delete async fun(path: string): nil
 ---@field query fun(opts?: FrecencyQueryOpts): FrecencyQueryEntry[]|string[]
@@ -20,7 +24,7 @@ local frecency = setmetatable({}, {
 
     return function(...)
       if not instance() then
-        rawset(self, "instance", require("frecency.klass").new())
+        rawset(self, "instance", require("frecency.klass").new(database))
         local is_async = key == "delete" or key == "validate_database" or key == "register"
         instance():setup(is_async)
       end
@@ -45,8 +49,9 @@ local function setup(ext_config)
   end
 
   local config = require "frecency.config"
-
   config.setup(ext_config)
+  local timer = require "frecency.timer"
+  timer.track "setup() start"
 
   vim.api.nvim_set_hl(0, "TelescopeBufferLoaded", { link = "String", default = true })
   vim.api.nvim_set_hl(0, "TelescopePathSeparator", { link = "Directory", default = true })
@@ -86,7 +91,15 @@ local function setup(ext_config)
     end,
   })
 
+  if config.bootstrap and vim.v.vim_did_enter == 0 then
+    database = require("frecency.database").new()
+    async_call(function()
+      database:start()
+    end)
+  end
+
   setup_done = true
+  timer.track "setup() finish"
 end
 
 return {
diff --git a/lua/frecency/klass.lua b/lua/frecency/klass.lua
index 7de54e4..78d0cd4 100644
--- a/lua/frecency/klass.lua
+++ b/lua/frecency/klass.lua
@@ -9,16 +9,25 @@ local wait = require "frecency.wait"
 local lazy_require = require "frecency.lazy_require"
 local async = lazy_require "plenary.async" --[[@as FrecencyPlenaryAsync]]
 
+---@enum FrecencyStatus
+local STATUS = {
+  NEW = 0,
+  SETUP_CALLED = 1,
+  SETUP_FINISHED = 2,
+}
+
 ---@class Frecency
 ---@field private buf_registered table<integer, boolean> flag to indicate the buffer is registered to the database.
 ---@field private database FrecencyDatabase
 ---@field private picker FrecencyPicker
+---@field private status FrecencyStatus
 local Frecency = {}
 
+---@param database? FrecencyDatabase
 ---@return Frecency
-Frecency.new = function()
-  local self = setmetatable({ buf_registered = {} }, { __index = Frecency }) --[[@as Frecency]]
-  self.database = Database.new()
+Frecency.new = function(database)
+  local self = setmetatable({ buf_registered = {}, status = STATUS.NEW }, { __index = Frecency }) --[[@as Frecency]]
+  self.database = database or Database.new()
   return self
 end
 
@@ -26,22 +35,35 @@ end
 ---@param is_async boolean
 ---@return nil
 function Frecency:setup(is_async)
+  if self.status >= STATUS.SETUP_CALLED then
+    return
+  end
+  self.status = STATUS.SETUP_CALLED
+  timer.track "frecency.setup() start"
+
   ---@async
   local function init()
-    timer.track "init() start"
     self.database:start()
     self:assert_db_entries()
     if config.auto_validate then
       self:validate_database()
     end
-    timer.track "init() finish"
+    timer.track "frecency.setup() finish"
+    self.status = STATUS.SETUP_FINISHED
   end
 
   if is_async then
     init()
-  else
-    wait(init)
+    return
   end
+
+  local ok, status = wait(init)
+  if ok then
+    return
+  end
+  -- NOTE: This means init() has failed. Try again.
+  self.status = STATUS.NEW
+  self:error(status == -1 and "init() never returns during the time" or "init() is interrupted during the time")
 end
 
 ---This can be calledBy `require("telescope").extensions.frecency.frecency`.
@@ -79,8 +101,11 @@ end
 ---@param force? boolean
 ---@return nil
 function Frecency:validate_database(force)
+  timer.track "validate_database() start"
   local unlinked = self.database:unlinked_entries()
+  timer.track "validate_database() calculate unlinked"
   if #unlinked == 0 or (not force and #unlinked < config.db_validate_threshold) then
+    timer.track "validate_database() finish: no unlinked"
     return
   end
   local function remove_entries()
@@ -89,6 +114,7 @@ function Frecency:validate_database(force)
   end
   if not config.db_safe_mode then
     remove_entries()
+    timer.track "validate_database() finish: removed"
     return
   end
   -- HACK: This is needed because the default implementaion of vim.ui.select()
diff --git a/lua/frecency/timer.lua b/lua/frecency/timer.lua
index 7d0fbf5..1dc5f49 100644
--- a/lua/frecency/timer.lua
+++ b/lua/frecency/timer.lua
@@ -18,21 +18,11 @@ function M.track(event)
   end
   if M.has_lazy then
     local stats = require "lazy.stats"
-    ---@param n integer
-    ---@return string
-    local function make_key(n)
-      return ("[telescope-frecency] %s: %d"):format(event, n)
+    local function make_key(num)
+      local key = num and ("[telescope-frecency] %s: %d"):format(event, num) or "[telescope-frecency] " .. event
+      return stats._stats.times[key] and make_key((num or 1) + 1) or key
     end
-    local key
-    local num = 0
-    while true do
-      key = make_key(num)
-      if not stats._stats.times[key] then
-        break
-      end
-      num = num + 1
-    end
-    stats.track(key)
+    stats.track(make_key())
   end
 end
 
diff --git a/lua/frecency/wait.lua b/lua/frecency/wait.lua
index a27efd9..a8f5be4 100644
--- a/lua/frecency/wait.lua
+++ b/lua/frecency/wait.lua
@@ -40,15 +40,8 @@ end
 
 ---@param f FrecencyWaitCallback
 ---@param opts FrecencyWaitConfig?
----@return nil
+---@return boolean ok
+---@return nil|-1|-2 status
 return function(f, opts)
-  local wait = Wait.new(f, opts)
-  local ok, status = wait:run()
-  if ok then
-    return
-  elseif status == -1 then
-    error "callback never returnes during the time"
-  elseif status == -2 then
-    error "callback is interrupted during the time"
-  end
+  return Wait.new(f, opts):run()
 end