diff --git a/README.md b/README.md
index 113e133..b1146ea 100644
--- a/README.md
+++ b/README.md
@@ -84,6 +84,8 @@ in the same line). Using treesitter for file preview highlighter etc
 
 - LSP Code Action, Code Lens, Code lens action
 
+- LRU cache for treesitter nodes
+
 # Why a new plugin
 
 I'd like to go beyond what the system is providing.
diff --git a/lua/navigator/gui.lua b/lua/navigator/gui.lua
index c3feba8..5736271 100644
--- a/lua/navigator/gui.lua
+++ b/lua/navigator/gui.lua
@@ -127,7 +127,7 @@ function M.new_list_view(opts)
   if opts.rawdata then
     data = items
   else
-    log(items)
+    trace(items)
     data = require"navigator.render".prepare_for_render(items, opts)
   end
 
diff --git a/lua/navigator/lru.lua b/lua/navigator/lru.lua
new file mode 100644
index 0000000..2e79a51
--- /dev/null
+++ b/lua/navigator/lru.lua
@@ -0,0 +1,150 @@
+-- lua-lru, LRU cache in Lua
+-- Copyright (c) 2015 Boris Nagaev
+-- See the LICENSE file for terms of use.
+local lru = {}
+
+function lru.new(max_size, max_bytes)
+
+  assert(max_size >= 1, "max_size must be >= 1")
+  assert(not max_bytes or max_bytes >= 1, "max_bytes must be >= 1")
+
+  -- current size
+  local size = 0
+  local bytes_used = 0
+
+  -- map is a hash map from keys to tuples
+  -- tuple: value, prev, next, key
+  -- prev and next are pointers to tuples
+  local map = {}
+
+  -- indices of tuple
+  local VALUE = 1
+  local PREV = 2
+  local NEXT = 3
+  local KEY = 4
+  local BYTES = 5
+
+  -- newest and oldest are ends of double-linked list
+  local newest = nil -- first
+  local oldest = nil -- last
+
+  local removed_tuple -- created in del(), removed in set()
+
+  -- remove a tuple from linked list
+  local function cut(tuple)
+    local tuple_prev = tuple[PREV]
+    local tuple_next = tuple[NEXT]
+    tuple[PREV] = nil
+    tuple[NEXT] = nil
+    if tuple_prev and tuple_next then
+      tuple_prev[NEXT] = tuple_next
+      tuple_next[PREV] = tuple_prev
+    elseif tuple_prev then
+      -- tuple is the oldest element
+      tuple_prev[NEXT] = nil
+      oldest = tuple_prev
+    elseif tuple_next then
+      -- tuple is the newest element
+      tuple_next[PREV] = nil
+      newest = tuple_next
+    else
+      -- tuple is the only element
+      newest = nil
+      oldest = nil
+    end
+  end
+
+  -- insert a tuple to the newest end
+  local function setNewest(tuple)
+    if not newest then
+      newest = tuple
+      oldest = tuple
+    else
+      tuple[NEXT] = newest
+      newest[PREV] = tuple
+      newest = tuple
+    end
+  end
+
+  local function del(key, tuple)
+    map[key] = nil
+    cut(tuple)
+    size = size - 1
+    bytes_used = bytes_used - (tuple[BYTES] or 0)
+    removed_tuple = tuple
+  end
+
+  -- removes elemenets to provide enough memory
+  -- returns last removed element or nil
+  local function makeFreeSpace(bytes)
+    while size + 1 > max_size or (max_bytes and bytes_used + bytes > max_bytes) do
+      assert(oldest, "not enough storage for cache")
+      del(oldest[KEY], oldest)
+    end
+  end
+
+  local function get(_, key)
+    local tuple = map[key]
+    if not tuple then
+      return nil
+    end
+    cut(tuple)
+    setNewest(tuple)
+    return tuple[VALUE]
+  end
+
+  local function set(_, key, value, bytes)
+    local tuple = map[key]
+    if tuple then
+      del(key, tuple)
+    end
+    if value ~= nil then
+      -- the value is not removed
+      bytes = max_bytes and (bytes or #value) or 0
+      makeFreeSpace(bytes)
+      local tuple1 = removed_tuple or {}
+      map[key] = tuple1
+      tuple1[VALUE] = value
+      tuple1[KEY] = key
+      tuple1[BYTES] = max_bytes and bytes
+      size = size + 1
+      bytes_used = bytes_used + bytes
+      setNewest(tuple1)
+    else
+      assert(key ~= nil, "Key may not be nil")
+    end
+    removed_tuple = nil
+  end
+
+  local function delete(_, key)
+    return set(_, key, nil)
+  end
+
+  local function mynext(_, prev_key)
+    local tuple
+    if prev_key then
+      tuple = map[prev_key][NEXT]
+    else
+      tuple = newest
+    end
+    if tuple then
+      return tuple[KEY], tuple[VALUE]
+    else
+      return nil
+    end
+  end
+
+  -- returns iterator for keys and values
+  local function lru_pairs()
+    return mynext, nil, nil
+  end
+
+  local mt = {
+    __index = {get = get, set = set, delete = delete, pairs = lru_pairs},
+    __pairs = lru_pairs
+  }
+
+  return setmetatable({}, mt)
+end
+
+return lru
diff --git a/lua/navigator/lspwrapper.lua b/lua/navigator/lspwrapper.lua
index 2751733..949ba34 100644
--- a/lua/navigator/lspwrapper.lua
+++ b/lua/navigator/lspwrapper.lua
@@ -1,4 +1,5 @@
 local M = {}
+
 local util = require "navigator.util"
 local gutil = require "guihua.util"
 local lsp = require "vim.lsp"
@@ -14,9 +15,8 @@ local is_win = vim.loop.os_uname().sysname:find("Windows")
 local path_sep = require"navigator.util".path_sep()
 local path_cur = require"navigator.util".path_cur()
 cwd = gutil.add_pec(cwd)
-ts_nodes = {}
-ts_nodes_time = {}
-
+local ts_nodes = require('navigator.lru').new(1000, 1024 * 1024)
+local ts_nodes_time = require('navigator.lru').new(1000)
 local TS_analysis_enabled = require"navigator".config_values().treesitter_analysis
 
 -- extract symbol from range
@@ -167,13 +167,18 @@ local function ts_functions(uri)
   local bufnr = vim.uri_to_bufnr(uri)
   local x = os.clock()
   trace(ts_nodes)
-  if ts_nodes[uri] ~= nil then
-    local t = ts_nodes_time[uri]
+  local tsnodes = ts_nodes:get(uri)
+  if tsnodes ~= nil then
+    log("get data from cache")
+    local t = ts_nodes_time:get(uri) or 0
     local fname = vim.uri_to_fname(uri)
     local modified = vim.fn.getftime(fname)
     if modified <= t then
       trace(t, modified)
-      return ts_nodes[uri]
+      return tsnodes
+    else
+      ts_nodes:delete(uri)
+      ts_nodes_time:delete(uri)
     end
   end
   local unload = false
@@ -189,9 +194,9 @@ local function ts_functions(uri)
     trace(cmd)
     -- vim.cmd(cmd)  -- todo: not sure if it is needed
   end
-  ts_nodes[uri] = funcs
-  ts_nodes_time[uri] = os.time()
-  trace(funcs, ts_nodes)
+  ts_nodes:set(uri, funcs)
+  ts_nodes_time:set(uri, os.time())
+  trace(funcs, ts_nodes:get(uri))
   trace(string.format("elapsed time: %.4f\n", os.clock() - x)) -- how long it tooks
   return funcs
 end
@@ -261,7 +266,7 @@ function M.locations_to_items(locations)
   end)
   local uri_def = {}
 
-  log(locations)
+  trace(locations)
   for i, loc in ipairs(locations) do
     local funcs = nil
     local item = lsp.util.locations_to_items({loc})[1]
diff --git a/lua/navigator/treesitter.lua b/lua/navigator/treesitter.lua
index 38c0df9..55c117e 100644
--- a/lua/navigator/treesitter.lua
+++ b/lua/navigator/treesitter.lua
@@ -2,6 +2,7 @@
 -- to fit in navigator.lua
 local gui = require "navigator.gui"
 local fn = vim.fn
+local lru = require('navigator.lru').new(500, 1024 * 1024)
 
 local ok, ts_locals = pcall(require, "nvim-treesitter.locals")
 
@@ -235,19 +236,41 @@ function M.goto_previous_usage(bufnr)
   return M.goto_adjacent_usage(bufnr, -1)
 end
 
+local function key(fname, filter)
+  return fname .. vim.inspect(filter)
+end
+
 local function get_all_nodes(bufnr, filter, summary)
-  trace(bufnr, filter, summary)
-  bufnr = bufnr or 0
-  summary = summary or false
-  if not parsers.has_parser() then
-    print("ts not loaded")
-  end
   local fname = vim.fn.expand("%:p:f")
   local uri = vim.uri_from_fname(fname)
   if bufnr ~= 0 then
     uri = vim.uri_from_bufnr(bufnr)
     fname = vim.uri_to_fname(uri)
   end
+
+  local ftime = vim.fn.getftime(fname)
+
+  local hash = key(fname, filter)
+
+  local result = lru:get(hash)
+  if result ~= nil and result.ftime == ftime then
+    log("get data from cache")
+    return result.nodes, result.length
+  end
+
+  if result ~= nil and result.ftime ~= ftime then
+    lru:delete(hash)
+  end
+
+  trace(bufnr, filter, summary)
+  if not bufnr then
+    print("get_all_node invalide bufnr")
+  end
+  summary = summary or false
+  if not parsers.has_parser() then
+    print("ts not loaded")
+  end
+
   path_sep = require"navigator.util".path_sep()
   path_cur = require"navigator.util".path_cur()
   local display_filename = fname:gsub(cwd .. path_sep, path_cur, 1)
@@ -366,6 +389,8 @@ local function get_all_nodes(bufnr, filter, summary)
     end
   end
   trace(all_nodes)
+  local nd = {nodes = all_nodes, ftime = vim.fn.getftime(fname), length = length}
+  lru:set(hash, nd)
   return all_nodes, length
 end