Avoid modification of SimulationTool and instead customise Inventory Cache

through SimulationTool_getInventoryCustomCache.

Also, if getInventoryList() calls could be handled with the custom cache,
fallback on generic cache which is in most cases better than nothing.

product/ERP5/Tool/SimulationTool.py

@@ -1301,59 +1301,42 @@ class SimulationTool(BaseTool):
         'quantity_unit_uid': quantity_unit_uid,
       }
 
-      # Required:
-      #   + ALTER TABLE stock ADD KEY `resource_section_node_date` (`resource_uid`, `section_uid`, `node_uid`, `date`);
-      #   + ALTER TABLE stock ADD KEY `variation_text_section_node` (`variation_text`, `section_uid`, `node_uid`);
-      if (optimisation__ and
-          'at_date' not in kw and
-          'from_date' not in kw and
-          'to_date' not in kw and
-          'variation_text' not in kw and
-          'resource_uid' in kw):
-        resource_uid_list = kw['resource_uid']
-        if not isinstance(resource_uid_list, (list, set, tuple)):
-          resource_uid_list = [resource_uid_list]
+      # Use Custom Inventory Cache implementation if any, before falling back
+      # on ERP5 Generic Cache implementation
+      cached_result = []
+      if optimisation__ and \
+              not getattr(self, 'SimulationTool_getInventoryCustomCache', None)(kw,
+                                                                                base_inventory_kw,
+                                                                                cached_result) and \
+              getattr(self, "Resource_zGetInventoryCacheResult", None) is not None and \
+              (not kw.get('from_date')) and \
+              'transformed_resource' not in kw:
+        # Here is the different kind of date
+        # from_date : >=
+        # to_date   : <
+        # at_date   : <=
+        # As we just have from_date, it means that we must use
+        # the to_date for the cache in order to avoid double computation
+        # of the same line
+        at_date = kw.pop("at_date", None)
+        if at_date is None:
+          to_date = kw.pop("to_date", None)
         else:
-          resource_uid_list = deepcopy(resource_uid_list)
-
-        for brain in self.portal_catalog(uid=resource_uid_list):
-          resource = brain.getObject()
-          if resource.getLotControlType() != '1':
-            resource_uid_list.remove(resource.getUid())
-
-        # Get available variations from the cache
-        from_date = None
-        variation_text_set = set()
-        for brain in self.Base_zGetKRAllInventoryCacheVariation(
-                resource_uid_list=resource_uid_list):
-          variation_text_set.add(brain['variation_text'])
-          # All the entries in the cache are generated at the same date
-          if from_date is None:
-            from_date = brain['to_date']
-
-        if from_date is not None:
-          node_uid_list = kw['node_uid']
-          if not isinstance(node_uid_list, (list, set, tuple)):
-            node_uid_list = [node_uid_list]
-          section_uid_list = kw['section_uid']
-          if not isinstance(section_uid_list, (list, set, tuple)):
-            section_uid_list = [section_uid_list]
-
-          # Get variations added since the cache was created
-          for brain in self.Base_zGetKRAllInventoryDeltaVariation(
-              from_date=from_date,
-              resource_uid_list=resource_uid_list,
-              # TODO-arnau: section_uid and node_uid seems always to be given to
-              # get*InventoryList...
-              section_uid_list=section_uid_list,
-              node_uid_list=node_uid_list):
-            variation_text_set.add(brain['variation_text'])
-
-          del kw['resource_uid']
-          kw['variation_text'] = list(variation_text_set)
+          # add one second so that we can use to_date
+          to_date = at_date + MYSQL_MIN_DATETIME_RESOLUTION
+        try:
+          cached_result, cached_date = self._getCachedInventoryList(
+              to_date=to_date,
+              sql_kw=kw,
+              **base_inventory_kw)
+        except StockOptimisationError:
+          kw['to_date'] = to_date
         else:
-          LOG("SimulationTool.getInventoryList", WARNING, "Not using Inventory Cache!")
-
+          if src__:
+            sql_source_list.extend(cached_result)
+          # Now must generate query for date diff
+          kw['to_date'] = to_date
+          kw['from_date'] = cached_date
       sql_kw, new_kw = self._generateKeywordDict(**kw)
       # Copy kw content as _generateSQLKeywordDictFromKeywordDict
       # remove some values from it
@@ -1367,11 +1350,142 @@ class SimulationTool(BaseTool):
       stock_sql_kw = self._generateSQLKeywordDictFromKeywordDict(
           table=default_stock_table, sql_kw=sql_kw, new_kw=new_kw_copy)
       stock_sql_kw.update(base_inventory_kw)
+      delta_result = self.Resource_zGetInventoryList(
+          **stock_sql_kw)
+      if src__:
+        sql_source_list.append(delta_result)
+        result = ';\n-- NEXT QUERY\n'.join(sql_source_list)
+      else:
+        if cached_result:
+            result = self._addBrainResults(delta_result, cached_result, new_kw)
+        else:
+            result = delta_result
+      return result
 
-      if 'variation_text' in kw:
-        stock_sql_kw['use_kr_inventory_cache'] = True
+    def getInventoryCacheLag(self):
+      """
+      Returns a duration, in days, for stock cache management.
+      If data in stock cache is older than lag compared to query's date
+      (at_date or to_date), then it becomes a "soft miss": use found value,
+      but add a new entry to cache at query's date minus half the lag.
+      So this value should be:
+      - Small enough that few enough rows need to be table-scanned for
+        average queries (probably queries against current date).
+      - Large enough that few enough documents get modified past that date,
+        otherwise cache entries would be removed from cache all the time.
+      """
+      return self.SimulationTool_getInventoryCacheLag()
+
+    def _getCachedInventoryList(self, to_date, sql_kw, stock_table_id, src__=False, **kw):
+      """
+      Try to get a cached inventory list result
+      If not existing, fill the cache
+      """
+      Resource_zGetInventoryList = self.Resource_zGetInventoryList
+      # Generate the SQL source without date parameter
+      # This will be the cache key
+      try:
+          no_date_kw = deepcopy(sql_kw)
+      except TypeError:
+          LOG("SimulationTool._getCachedInventoryList", WARNING,
+              "Failed copying sql_kw, disabling stock cache",
+              error=exc_info())
+          raise StockOptimisationError
+      no_date_sql_kw, no_date_new_kw = self._generateKeywordDict(**no_date_kw)
+      no_date_stock_sql_kw = self._generateSQLKeywordDictFromKeywordDict(
+        table=stock_table_id, sql_kw=no_date_sql_kw,
+        new_kw=no_date_new_kw)
+      kw.update(no_date_stock_sql_kw)
+      if src__:
+        sql_source_list = []
+      # Generate the cache key (md5 of query source)
+      sql_text_hash = md5(Resource_zGetInventoryList(
+        stock_table_id=stock_table_id,
+        src__=1,
+        **kw)).digest()
+      # Try to get result from cache
+      Resource_zGetInventoryCacheResult = self.Resource_zGetInventoryCacheResult
+      inventory_cache_kw = {'query': sql_text_hash}
+      if to_date is not None:
+        inventory_cache_kw['date'] = to_date
+      try:
+          cached_sql_result = Resource_zGetInventoryCacheResult(**inventory_cache_kw)
+      except ProgrammingError:
+          # First use of the optimisation, we need to create the table
+          LOG("SimulationTool._getCachedInventoryList", INFO,
+              "Creating inventory cache stock")
+          if src__:
+              sql_source_list.append(self.SimulationTool_zCreateInventoryCache(src__=1))
+          else:
+              self.SimulationTool_zCreateInventoryCache()
+          cached_sql_result = None
 
-      return self.Resource_zGetInventoryList(**stock_sql_kw)
+      if src__:
+        sql_source_list.append(Resource_zGetInventoryCacheResult(src__=1, **inventory_cache_kw))
+      if cached_sql_result:
+        brain_result = loads(cached_sql_result[0].result)
+        # Rebuild the brains
+        cached_result = Results(
+          (brain_result['items'], brain_result['data']),
+          brains=getBrain(
+            Resource_zGetInventoryList.class_file_,
+            Resource_zGetInventoryList.class_name_,
+          ),
+          parent=self,
+        )
+      else:
+        cached_result = []
+      cache_lag = self.getInventoryCacheLag()
+      if cached_sql_result and (to_date is None or (to_date - DateTime(cached_sql_result[0].date) < cache_lag)):
+        cached_date = DateTime(cached_sql_result[0].date)
+        result = cached_result
+      elif to_date is not None:
+        # Cache miss, or hit with old data: store a new entry in cache.
+        # Don't store it at to_date, as it risks being flushed soon (ie, when
+        # any document older than to_date gets reindexed in stock table).
+        # Don't store it at to_date - cache_lag, as it would risk expiring
+        # soon as we store it (except if to_date is fixed for many queries,
+        # which we cannot tell here).
+        # So store it at half the cache_lag before to_date.
+        cached_date = to_date - cache_lag / 2
+        new_cache_kw = deepcopy(sql_kw)
+        if cached_result:
+          # We can use cached result to generate new cache result
+          new_cache_kw['from_date'] = DateTime(cached_sql_result[0].date)
+        sql_kw, new_kw = self._generateKeywordDict(
+          to_date=cached_date,
+          **new_cache_kw)
+        kw.update(self._generateSQLKeywordDictFromKeywordDict(
+            table=stock_table_id,
+            sql_kw=sql_kw,
+            new_kw=new_kw,
+          )
+        )
+        new_result = Resource_zGetInventoryList(
+          stock_table_id=stock_table_id,
+          src__=src__,
+          **kw)
+        if src__:
+          sql_source_list.append(new_result)
+        else:
+          result = self._addBrainResults(new_result, cached_result, new_kw)
+          self.Resource_zInsertInventoryCacheResult(
+            query=sql_text_hash,
+            date=cached_date,
+            result=dumps({
+              'items': result.__items__,
+              'data': result._data,
+            }),
+          )
+      else:
+        # Cache miss and this getInventory() not specifying to_date,
+        # and other getInventory() have not created usable caches.
+        # In such case, do not create cache, do not use cache.
+        result = []
+        cached_date = None
+      if src__:
+        result = sql_source_list
+      return result, cached_date
 
     def _addBrainResults(self, first_result, second_result, new_kw):
       """