From d621b4c1a79a0c90367b5013db0168b143170b91 Mon Sep 17 00:00:00 2001
From: Matchu <matchu1993@gmail.com>
Date: Mon, 17 Aug 2020 01:33:34 -0700
Subject: [PATCH] fix caching for petTypeLoader

Oops, of course, we weren't actually taking proper advantage of the dataloader here! The queries got over-complicated, but more importantly, subsequent requests to the same loader would re-submit the query!

I noticed it in the SearchPanel operation, in this Honeycomb trace:
https://ui.honeycomb.io/openneo/datasets/dress-to-impress--2020-/trace/aMuhsTjQFZY
---
 src/server/loaders.js               | 47 +++++++++++++++--------------
 src/server/query-tests/Item.test.js |  6 +---
 2 files changed, 26 insertions(+), 27 deletions(-)

diff --git a/src/server/loaders.js b/src/server/loaders.js
index fbf29b8..13939c2 100644
--- a/src/server/loaders.js
+++ b/src/server/loaders.js
@@ -196,32 +196,35 @@ const buildPetTypeLoader = (db) =>
   });
 
 const buildPetTypeBySpeciesAndColorLoader = (db, loaders) =>
-  new DataLoader(async (speciesAndColorPairs) => {
-    const conditions = [];
-    const values = [];
-    for (const { speciesId, colorId } of speciesAndColorPairs) {
-      conditions.push("(species_id = ? AND color_id = ?)");
-      values.push(speciesId, colorId);
-    }
+  new DataLoader(
+    async (speciesAndColorPairs) => {
+      const conditions = [];
+      const values = [];
+      for (const { speciesId, colorId } of speciesAndColorPairs) {
+        conditions.push("(species_id = ? AND color_id = ?)");
+        values.push(speciesId, colorId);
+      }
 
-    const [rows, _] = await db.execute(
-      `SELECT * FROM pet_types WHERE ${conditions.join(" OR ")}`,
-      values
-    );
+      const [rows, _] = await db.execute(
+        `SELECT * FROM pet_types WHERE ${conditions.join(" OR ")}`,
+        values
+      );
 
-    const entities = rows.map(normalizeRow);
-    const entitiesBySpeciesAndColorPair = new Map(
-      entities.map((e) => [`${e.speciesId},${e.colorId}`, e])
-    );
+      const entities = rows.map(normalizeRow);
+      const entitiesBySpeciesAndColorPair = new Map(
+        entities.map((e) => [`${e.speciesId},${e.colorId}`, e])
+      );
 
-    for (const petType of entities) {
-      loaders.petTypeLoader.prime(petType.id, petType);
-    }
+      for (const petType of entities) {
+        loaders.petTypeLoader.prime(petType.id, petType);
+      }
 
-    return speciesAndColorPairs.map(({ speciesId, colorId }) =>
-      entitiesBySpeciesAndColorPair.get(`${speciesId},${colorId}`)
-    );
-  });
+      return speciesAndColorPairs.map(({ speciesId, colorId }) =>
+        entitiesBySpeciesAndColorPair.get(`${speciesId},${colorId}`)
+      );
+    },
+    { cacheKeyFn: ({ speciesId, colorId }) => `${speciesId},${colorId}` }
+  );
 
 const buildSwfAssetLoader = (db) =>
   new DataLoader(async (swfAssetIds) => {
diff --git a/src/server/query-tests/Item.test.js b/src/server/query-tests/Item.test.js
index 191af06..774b0b9 100644
--- a/src/server/query-tests/Item.test.js
+++ b/src/server/query-tests/Item.test.js
@@ -111,14 +111,10 @@ describe("Item", () => {
           ],
         ],
         Array [
-          "SELECT * FROM pet_types WHERE (species_id = ? AND color_id = ?) OR (species_id = ? AND color_id = ?) OR (species_id = ? AND color_id = ?)",
+          "SELECT * FROM pet_types WHERE (species_id = ? AND color_id = ?)",
           Array [
             "54",
             "75",
-            "54",
-            "75",
-            "54",
-            "75",
           ],
         ],
         Array [