1 files changed, 68 insertions, 2 deletions
diff --git a/lib/pleroma/telemetry/logger.ex b/lib/pleroma/telemetry/logger.ex
index 10165c1b2..35e245237 100644
--- a/lib/pleroma/telemetry/logger.ex
+++ b/lib/pleroma/telemetry/logger.ex
@@ -12,10 +12,16 @@ defmodule Pleroma.Telemetry.Logger do
     [:pleroma, :connection_pool, :reclaim, :stop],
     [:pleroma, :connection_pool, :provision_failure],
     [:pleroma, :connection_pool, :client, :dead],
-    [:pleroma, :connection_pool, :client, :add]
+    [:pleroma, :connection_pool, :client, :add],
+    [:pleroma, :repo, :query]
   ]
   def attach do
-    :telemetry.attach_many("pleroma-logger", @events, &handle_event/4, [])
+    :telemetry.attach_many(
+      "pleroma-logger",
+      @events,
+      &Pleroma.Telemetry.Logger.handle_event/4,
+      []
+    )
   end
 
   # Passing anonymous functions instead of strings to logger is intentional,
@@ -87,4 +93,64 @@ defmodule Pleroma.Telemetry.Logger do
   end
 
   def handle_event([:pleroma, :connection_pool, :client, :add], _, _, _), do: :ok
+
+  def handle_event(
+        [:pleroma, :repo, :query] = _name,
+        %{query_time: query_time} = measurements,
+        %{source: source} = metadata,
+        config
+      ) do
+    logging_config = Pleroma.Config.get([:telemetry, :slow_queries_logging], [])
+
+    if logging_config[:enabled] &&
+         logging_config[:min_duration] &&
+         query_time > logging_config[:min_duration] and
+         (is_nil(logging_config[:exclude_sources]) or
+            source not in logging_config[:exclude_sources]) do
+      log_slow_query(measurements, metadata, config)
+    else
+      :ok
+    end
+  end
+
+  defp log_slow_query(
+         %{query_time: query_time} = _measurements,
+         %{source: _source, query: query, params: query_params, repo: repo} = _metadata,
+         _config
+       ) do
+    sql_explain =
+      with {:ok, %{rows: explain_result_rows}} <-
+             repo.query("EXPLAIN " <> query, query_params, log: false) do
+        Enum.map_join(explain_result_rows, "\n", & &1)
+      end
+
+    {:current_stacktrace, stacktrace} = Process.info(self(), :current_stacktrace)
+
+    pleroma_stacktrace =
+      Enum.filter(stacktrace, fn
+        {__MODULE__, _, _, _} ->
+          false
+
+        {mod, _, _, _} ->
+          mod
+          |> to_string()
+          |> String.starts_with?("Elixir.Pleroma.")
+      end)
+
+    Logger.warn(fn ->
+      """
+      Slow query!
+
+      Total time: #{round(query_time / 1_000)} ms
+
+      #{query}
+
+      #{inspect(query_params, limit: :infinity)}
+
+      #{sql_explain}
+
+      #{Exception.format_stacktrace(pleroma_stacktrace)}
+      """
+    end)
+  end
 end