Use WHERE name filter in more places (#6157)

* refactor: move derived_name_filter to WhereBuilder, use matching_toplevel_filters

* feat: apply name filter optimization to base event queries

* feat: apply name filter optimization to funnel queries

* refactor: call WhereBuilder.derived_name_filter directly

* Remove unused alias

Author: ukutaht

extra/lib/plausible/stats/funnel.ex

@@ -13,7 +13,7 @@ defmodule Plausible.Stats.Funnel do
   import Plausible.Stats.SQL.Fragments
 
   alias Plausible.ClickhouseRepo
-  alias Plausible.Stats.Base
+  alias Plausible.Stats.{Base, Query}
 
   @spec funnel(Plausible.Site.t(), Plausible.Stats.Query.t(), Funnel.t() | pos_integer()) ::
           {:ok, map()} | {:error, :funnel_not_found}
@@ -28,8 +28,11 @@ defmodule Plausible.Stats.Funnel do
   end
 
   def funnel(_site, query, %Funnel{} = funnel) do
+    goals = Enum.map(funnel.steps, & &1.goal)
+
     funnel_data =
       query
+      |> Query.set(preloaded_goals: %{all: [], matching_toplevel_filters: goals})
       |> Base.base_event_query()
       |> query_funnel(funnel)
 

lib/plausible/stats/base.ex

@@ -27,7 +27,11 @@ defmodule Plausible.Stats.Base do
   end
 
   defp query_events(query) do
-    q = from(e in "events_v2", where: ^SQL.WhereBuilder.build(:events, query))
+    q =
+      from(e in "events_v2",
+        where: ^SQL.WhereBuilder.build(:events, query),
+        where: ^SQL.WhereBuilder.derived_name_filter(query)
+      )
 
     on_ee do
       q = Plausible.Stats.Sampling.add_query_hint(q, query)

lib/plausible/stats/sql/query_builder.ex

@@ -8,7 +8,7 @@ defmodule Plausible.Stats.SQL.QueryBuilder do
   import Plausible.Stats.Imported
   import Plausible.Stats.Util
 
-  alias Plausible.Stats.{Query, Filters, QueryOptimizer, TableDecider, SQL}
+  alias Plausible.Stats.{Query, QueryOptimizer, TableDecider, SQL}
   alias Plausible.Stats.SQL.Expression
   alias Plausible.Stats.Legacy.TimeOnPage
 
@@ -36,7 +36,7 @@ defmodule Plausible.Stats.SQL.QueryBuilder do
       from(
         e in "events_v2",
         where: ^SQL.WhereBuilder.build(:events, events_query),
-        where: ^derived_name_filter(events_query),
+        where: ^SQL.WhereBuilder.derived_name_filter(events_query),
         select: ^select_event_metrics(events_query)
       )
 
@@ -111,6 +111,7 @@ defmodule Plausible.Stats.SQL.QueryBuilder do
       events_q =
         from(e in "events_v2",
           where: ^SQL.WhereBuilder.build(:events, query),
+          where: ^SQL.WhereBuilder.derived_name_filter(query),
           select: %{
             session_id: fragment("DISTINCT ?", e.session_id),
             _sample_factor: fragment("_sample_factor")
@@ -130,40 +131,6 @@ defmodule Plausible.Stats.SQL.QueryBuilder do
     end
   end
 
-  defp derived_name_filter(events_query) do
-    cond do
-      goal_breakdown?(events_query) ->
-        names = goal_event_names(events_query.preloaded_goals.all)
-        dynamic([e], e.name in ^names)
-
-      # Goal filters already add precise name conditions via Goals.add_filter
-      Filters.filtering_on_dimension?(events_query.filters, "event:goal") ->
-        true
-
-      :time_on_page not in events_query.metrics and :scroll_depth not in events_query.metrics ->
-        dynamic([e], e.name != "engagement")
-
-      true ->
-        true
-    end
-  end
-
-  defp goal_breakdown?(query) do
-    "event:goal" in query.dimensions
-  end
-
-  defp goal_event_names(goals) do
-    goals
-    |> Enum.map(fn goal ->
-      case Plausible.Goal.type(goal) do
-        :event -> goal.event_name
-        :page -> "pageview"
-        :scroll -> "engagement"
-      end
-    end)
-    |> Enum.uniq()
-  end
-
   defp select_event_metrics(query) do
     query.metrics
     |> Enum.map(&SQL.Expression.event_metric(&1, query))

lib/plausible/stats/sql/where_builder.ex

@@ -18,6 +18,43 @@ defmodule Plausible.Stats.SQL.WhereBuilder do
     :exit_page_hostname
   ]
 
+  @doc """
+  Builds a WHERE condition to restrict event name, reducing unnecessary reads of
+  engagement events when they are not needed.
+
+  - Goal filters: no restriction (Goals.add_filter already adds precise name conditions)
+  - Preloaded goals present: restrict to only the event names relevant to those goals
+  - Default: exclude engagement events unless time_on_page or scroll_depth metrics are requested
+  """
+  def derived_name_filter(query) do
+    cond do
+      Plausible.Stats.Filters.filtering_on_dimension?(query.filters, "event:goal") ->
+        true
+
+      query.preloaded_goals.matching_toplevel_filters != [] ->
+        names = goal_event_names(query.preloaded_goals.matching_toplevel_filters)
+        dynamic([e], e.name in ^names)
+
+      :time_on_page not in query.metrics and :scroll_depth not in query.metrics ->
+        dynamic([e], e.name != "engagement")
+
+      true ->
+        true
+    end
+  end
+
+  defp goal_event_names(goals) do
+    goals
+    |> Enum.map(fn goal ->
+      case Plausible.Goal.type(goal) do
+        :event -> goal.event_name
+        :page -> "pageview"
+        :scroll -> "engagement"
+      end
+    end)
+    |> Enum.uniq()
+  end
+
   @doc "Builds WHERE clause for a given Query against sessions or events table"
   def build(table, query) do
     base_condition = filter_site_time_range(table, query)