⚡️(backend) increase nb_accesses cache TTL

The nb_accesses cache TTL was very short, 30 seconds. That mean that the
user will hit the cache for a very short period and the cache is
probably not be hit. This is what we can see in the slow queries from
the pg_stat_statements table. The query to compute the nb_accesses is
executed a little bit less than the number of queries to list or
retrieve documents, meaning the cache is not used.

documentation/env.md

@@ -86,6 +86,7 @@ These are the environment variables you can set for the `impress-backend` contai
 | DOCSPEC_API_URL                                 | URL to endpoint of DocSpec conversion API                                                                                                                                  |                                                                         |
 | DOCUMENT_IMAGE_MAX_SIZE                         | Maximum size of document in bytes                                                                                                                                          | 10485760                                                                |
 | DOCUMENT_ALL_ENDPOINT_ENABLED                   | Enable or not the endpoint /api/v1.0/documents/all/                                                                                                                        | true                                                                    |
+| DOCUMENT_NB_ACCESSES_CACHE_TIMEOUT              | Time, in seconds, the number of accesses for a document stay in cache.                                                                                                     | 600                                                                     |
 | FRONTEND_CSS_URL                                | To add a external css file to the app                                                                                                                                      |                                                                         |
 | FRONTEND_JS_URL                                 | To add a external js file to the app                                                                                                                                       |                                                                         |
 | FRONTEND_HOMEPAGE_FEATURE_ENABLED               | Frontend feature flag to display the homepage                                                                                                                              | false                                                                   |

src/backend/core/api/viewsets.py

@@ -1049,6 +1049,9 @@ class DocumentViewSet(
                     defaults={"role": models.RoleChoices.OWNER},
                 )
 
+        # Invalidate the nb_accesses cache, the value has probably changed after the move.
+        document.invalidate_nb_accesses_cache()
+
         posthog_capture(
             PosthogEventName.DOC_MOVED,
             user,

src/backend/core/models.py

@@ -1193,7 +1193,9 @@ class Document(MP_Node, BaseModel):
                     document__ancestors_deleted_at__isnull=True,
                 ).count(),
             )
-            cache.set(cache_key, nb_accesses)
+            cache.set(
+                cache_key, nb_accesses, settings.DOCUMENT_NB_ACCESSES_CACHE_TIMEOUT
+            )
 
         return nb_accesses
 

src/backend/impress/settings.py

@@ -990,6 +990,12 @@ class Base(Configuration):
         environ_prefix=None,
     )
 
+    DOCUMENT_NB_ACCESSES_CACHE_TIMEOUT = values.IntegerValue(
+        default=600,
+        environ_name="DOCUMENT_NB_ACCESSES_CACHE_TIMEOUT",
+        environ_prefix=None,
+    )
+
     # Logging
     # We want to make it easy to log to console but by default we log production
     # to Sentry and don't want to log to console.