diff --git a/addons/attachment_indexation/models/ir_attachment.py b/addons/attachment_indexation/models/ir_attachment.py
index c6017f010c8..164ef46e800 100644
--- a/addons/attachment_indexation/models/ir_attachment.py
+++ b/addons/attachment_indexation/models/ir_attachment.py
@@ -6,6 +6,7 @@ import xml.dom.minidom
 import zipfile
 
 from odoo import api, models
+from odoo.tools.lru import LRU
 
 _logger = logging.getLogger(__name__)
 
@@ -21,6 +22,8 @@ except ImportError:
 FTYPES = ['docx', 'pptx', 'xlsx', 'opendoc', 'pdf']
 
 
+index_content_cache = LRU(1)
+
 def textToString(element):
     buff = u""
     for node in element.childNodes:
@@ -121,10 +124,19 @@ class IrAttachment(models.Model):
         return buf
 
     @api.model
-    def _index(self, bin_data, mimetype):
+    def _index(self, bin_data, mimetype, checksum=None):
+        if checksum:
+            cached_content = index_content_cache.get(checksum)
+            if cached_content:
+                return cached_content
+        res = False
         for ftype in FTYPES:
             buf = getattr(self, '_index_%s' % ftype)(bin_data)
             if buf:
-                return buf.replace('\x00', '')
+                res = buf.replace('\x00', '')
+                break
 
-        return super(IrAttachment, self)._index(bin_data, mimetype)
+        res = res or super(IrAttachment, self)._index(bin_data, mimetype, checksum=checksum)
+        if checksum:
+            index_content_cache[checksum] = res
+        return res
diff --git a/odoo/addons/base/models/ir_attachment.py b/odoo/addons/base/models/ir_attachment.py
index b881cc49f85..11cbbc96871 100644
--- a/odoo/addons/base/models/ir_attachment.py
+++ b/odoo/addons/base/models/ir_attachment.py
@@ -251,10 +251,15 @@ class IrAttachment(models.Model):
                 self._file_delete(fname)
 
     def _get_datas_related_values(self, data, mimetype):
+        checksum = self._compute_checksum(data)
+        try:
+            index_content = self._index(data, mimetype, checksum=checksum)
+        except TypeError:
+            index_content = self._index(data, mimetype)
         values = {
             'file_size': len(data),
-            'checksum': self._compute_checksum(data),
-            'index_content': self._index(data, mimetype),
+            'checksum': checksum,
+            'index_content': index_content,
             'store_fname': False,
             'db_datas': data,
         }
@@ -360,7 +365,7 @@ class IrAttachment(models.Model):
         return values
 
     @api.model
-    def _index(self, bin_data, file_type):
+    def _index(self, bin_data, file_type, checksum=None):
         """ compute the index content of the given binary data.
             This is a python implementation of the unix command 'strings'.
             :param bin_data : datas in binary form
@@ -652,7 +657,7 @@ class IrAttachment(models.Model):
                 ))
 
             # 'check()' only uses res_model and res_id from values, and make an exists.
-            # We can group the values by model, res_id to make only one query when 
+            # We can group the values by model, res_id to make only one query when
             # creating multiple attachments on a single record.
             record_tuple = (values.get('res_model'), values.get('res_id'))
             record_tuple_set.add(record_tuple)