From 30525a18f3a99681c2f687c0f54a167a4e2a5f94 Mon Sep 17 00:00:00 2001
From: Graham McIntire <graham@mcintire.me>
Date: Mon, 20 Apr 2026 16:56:14 -0500
Subject: [PATCH] perf(status): collapse 7 contact-count queries to a single
 FILTER scan

count_unprocessed_raw fired seven separate COUNT(*) scans on the
contacts table every 2 s refresh (total, terrain, hrrr, weather, iemre,
radar, all-done). Each one went through the 58k+ row table
independently, so the status page was hitting Postgres with ~3.5 full
scans per second of connected viewer time.

A single query with COUNT(*) FILTER clauses pulls every count in one
sequential scan. Same result, roughly 1/7 the CPU on Postgres.
---
 lib/microwaveprop_web/live/status_live.ex | 59 ++++++++++-------------
 1 file changed, 25 insertions(+), 34 deletions(-)

diff --git a/lib/microwaveprop_web/live/status_live.ex b/lib/microwaveprop_web/live/status_live.ex
index bb895fea..f3dc2c5b 100644
--- a/lib/microwaveprop_web/live/status_live.ex
+++ b/lib/microwaveprop_web/live/status_live.ex
@@ -83,21 +83,35 @@ defmodule MicrowavepropWeb.StatusLive do
   end
 
   defp count_unprocessed_raw do
-    incomplete = [:pending, :queued, :processing, :failed]
-    done = [:complete, :unavailable]
-
-    total = Repo.one(from(c in Contact, where: not is_nil(c.pos1), select: count()))
-    terrain = count_incomplete(:terrain_status, incomplete)
-    hrrr = count_incomplete(:hrrr_status, incomplete)
-    weather = count_incomplete(:weather_status, incomplete)
-    iemre = count_incomplete(:iemre_status, incomplete)
-    radar = count_incomplete(:radar_status, incomplete)
+    # Previously issued 7 separate `SELECT COUNT(*) FROM contacts WHERE
+    # <field> IN (...)` queries. Postgres ran 7 index scans over the
+    # same 58k+ row table on every 2s status refresh; collapse into a
+    # single scan that returns every needed count via FILTER clauses.
+    %{rows: [[total, terrain, hrrr, weather, iemre, radar, all_done]]} =
+      Repo.query!("""
+      SELECT
+        COUNT(*) FILTER (WHERE pos1 IS NOT NULL),
+        COUNT(*) FILTER (WHERE pos1 IS NOT NULL
+          AND terrain_status::text IN ('pending','queued','processing','failed')),
+        COUNT(*) FILTER (WHERE pos1 IS NOT NULL
+          AND hrrr_status::text IN ('pending','queued','processing','failed')),
+        COUNT(*) FILTER (WHERE pos1 IS NOT NULL
+          AND weather_status::text IN ('pending','queued','processing','failed')),
+        COUNT(*) FILTER (WHERE pos1 IS NOT NULL
+          AND iemre_status::text IN ('pending','queued','processing','failed')),
+        COUNT(*) FILTER (WHERE pos1 IS NOT NULL
+          AND radar_status::text IN ('pending','queued','processing','failed')),
+        COUNT(*) FILTER (WHERE pos1 IS NOT NULL
+          AND hrrr_status::text IN ('complete','unavailable')
+          AND weather_status::text IN ('complete','unavailable')
+          AND terrain_status::text IN ('complete','unavailable')
+          AND iemre_status::text IN ('complete','unavailable'))
+      FROM contacts
+      """)
 
     narr_candidates = count_narr_candidates()
     narr_done = count_narr_done()
 
-    all_done = count_all_done(done)
-
     %{
       terrain: terrain,
       hrrr: hrrr,
@@ -159,29 +173,6 @@ defmodule MicrowavepropWeb.StatusLive do
     done
   end
 
-  defp count_incomplete(status_field, statuses) do
-    Repo.one(
-      from(c in Contact,
-        where: field(c, ^status_field) in ^statuses and not is_nil(c.pos1),
-        select: count()
-      )
-    )
-  end
-
-  defp count_all_done(done) do
-    Repo.one(
-      from(c in Contact,
-        where:
-          not is_nil(c.pos1) and
-            c.hrrr_status in ^done and
-            c.weather_status in ^done and
-            c.terrain_status in ^done and
-            c.iemre_status in ^done,
-        select: count()
-      )
-    )
-  end
-
   defp fetch_grid_tasks_stats do
     Cache.fetch_or_store({__MODULE__, :grid_tasks_stats}, 2_000, fn -> fetch_grid_tasks_stats_raw() end)
   end