diff --git a/swh/search/elasticsearch.py b/swh/search/elasticsearch.py
--- a/swh/search/elasticsearch.py
+++ b/swh/search/elasticsearch.py
@@ -46,14 +46,12 @@
             index='origin',
             body={
                 'properties': {
+                    'sha1': {
+                        'type': 'keyword',
+                        'doc_values': True,
+                    },
                     'url': {
                         'type': 'text',
-                        # TODO: consider removing fielddata when
-                        # swh-storage allows querying by hash, so the
-                        # full URL does not have to be stored in ES'
-                        # memory. See:
-                        # https://www.elastic.co/guide/en/elasticsearch/reference/current/fielddata.html#before-enabling-fielddata
-                        'fielddata': True,
                         # To split URLs into token on any character
                         # that is not alphanumerical
                         'analyzer': 'simple',
@@ -80,22 +78,31 @@
             }
         )
 
+    @remote_api_endpoint('flush')
+    def flush(self) -> None:
+        """Blocks until all previous calls to _update() are completely
+        applied."""
+        self._backend.indices.refresh(index='_all')
+
     @remote_api_endpoint('origin/update')
     def origin_update(self, documents: Iterable[dict]) -> None:
         documents = map(_sanitize_origin, documents)
+        documents_with_sha1 = ((origin_identifier(document), document)
+                               for document in documents)
         actions = [
             {
                 '_op_type': 'update',
-                '_id': origin_identifier(document),
+                '_id': sha1,
                 '_index': 'origin',
-                'doc': document,
+                'doc': {
+                    **document,
+                    'sha1': sha1,
+                },
                 'doc_as_upsert': True,
             }
-            for document in documents
+            for (sha1, document) in documents_with_sha1
         ]
-        # TODO: make refresh='wait_for' configurable (we don't need it
-        # in production, it will probably be a performance issue)
-        bulk(self._backend, actions, index='origin', refresh='wait_for')
+        bulk(self._backend, actions, index='origin')
 
     def origin_dump(self) -> Iterator[model.Origin]:
         """Returns all content in Elasticsearch's index. Not exposed
@@ -180,7 +187,7 @@
             'size': count,
             'sort': [
                 {'_score': 'desc'},
-                {'_id': 'asc'},
+                {'sha1': 'asc'},
             ]
         }
         if page_token:
@@ -189,7 +196,7 @@
                 base64.b64decode(page_token))
             body['search_after'] = \
                 [page_token_content[b'score'],
-                 page_token_content[b'id'].decode('ascii')]
+                 page_token_content[b'sha1'].decode('ascii')]
 
         res = self._backend.search(
             index='origin',
@@ -203,7 +210,7 @@
             last_hit = hits[-1]
             next_page_token_content = {
                 b'score': last_hit['_score'],
-                b'id': last_hit['_id'],
+                b'sha1': last_hit['_source']['sha1'],
             }
             next_page_token = base64.b64encode(msgpack.dumps(
                 next_page_token_content))  # type: Optional[bytes]
diff --git a/swh/search/in_memory.py b/swh/search/in_memory.py
--- a/swh/search/in_memory.py
+++ b/swh/search/in_memory.py
@@ -43,6 +43,9 @@
         self._origins = defaultdict(dict)  # type: Dict[str, Dict[str, Any]]
         self._origin_ids = []  # type: List[str]
 
+    def flush(self) -> None:
+        pass
+
     _url_splitter = re.compile(r'\W')
 
     @remote_api_endpoint('origin/update')
diff --git a/swh/search/tests/test_cli.py b/swh/search/tests/test_cli.py
--- a/swh/search/tests/test_cli.py
+++ b/swh/search/tests/test_cli.py
@@ -85,6 +85,8 @@
         assert result.exit_code == 0, result.output
         assert result.output == expected_output
 
+        self.search.flush()
+
         results = self.search.origin_search(url_pattern='foobar')
         assert results == {'next_page_token': None, 'results': [
             {'url': 'http://foobar.baz'}]}
@@ -123,6 +125,8 @@
         assert result.exit_code == 0, result.output
         assert result.output == expected_output
 
+        self.search.flush()
+
         results = self.search.origin_search(url_pattern='foobar',
                                             with_visit=True)
         assert results == {'next_page_token': None, 'results': [
diff --git a/swh/search/tests/test_search.py b/swh/search/tests/test_search.py
--- a/swh/search/tests/test_search.py
+++ b/swh/search/tests/test_search.py
@@ -15,6 +15,7 @@
             {'url': 'http://barbaz.qux'},
             {'url': 'http://qux.quux'},
         ])
+        self.search.flush()
 
         results = self.search.origin_search(url_pattern='foobar')
         assert results == {'next_page_token': None, 'results': [
@@ -39,6 +40,7 @@
             {'url': 'http://barbaz.qux'},
             {'url': 'http://qux.quux'},
         ])
+        self.search.flush()
 
         results = self.search.origin_search(url_pattern='qu')
         assert results['next_page_token'] is None
@@ -58,6 +60,7 @@
         self.search.origin_update([
             {'url': 'http://foobar.baz', 'has_visits': True},
         ])
+        self.search.flush()
 
         results = self.search.origin_search(
             url_pattern='foobar', with_visit=True)
@@ -68,6 +71,7 @@
         self.search.origin_update([
             {'url': 'http://foobar.baz'},
         ])
+        self.search.flush()
 
         results = self.search.origin_search(
             url_pattern='foobar', with_visit=True)
@@ -76,6 +80,7 @@
         self.search.origin_update([
             {'url': 'http://foobar.baz', 'has_visits': True},
         ])
+        self.search.flush()
 
         results = self.search.origin_search(
             url_pattern='foobar', with_visit=True)
@@ -103,6 +108,7 @@
                 }
             },
         ])
+        self.search.flush()
 
         results = self.search.origin_search(metadata_pattern='foo')
         assert results == {'next_page_token': None, 'results': [
@@ -138,6 +144,7 @@
                 }
             },
         ])
+        self.search.flush()
 
         results = self.search.origin_search(metadata_pattern='foo')
         assert results == {'next_page_token': None, 'results': [
@@ -165,6 +172,7 @@
             {'url': 'http://origin2/foo/bar'},
             {'url': 'http://origin3/foo/bar/baz'},
         ])
+        self.search.flush()
 
         results = stream_results(
             self.search.origin_search,
@@ -227,6 +235,7 @@
                 }
             },
         ])
+        self.search.flush()
 
         results = stream_results(
             self.search.origin_search,