From efce1c839ef971cf016fd21408d35f2ea9cbb349 Mon Sep 17 00:00:00 2001
From: mike12345567 <me@michaeldrury.co.uk>
Date: Fri, 9 Oct 2020 20:06:54 +0100
Subject: [PATCH 1/2] Major performance boost to attachLinks -> makes CSV
 upload much more snappy.

---
 packages/server/src/db/linkedRecords/index.js | 23 ++++++++++---------
 .../server/src/db/linkedRecords/linkUtils.js  |  2 ++
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/packages/server/src/db/linkedRecords/index.js b/packages/server/src/db/linkedRecords/index.js
index 115553696c..842900f815 100644
--- a/packages/server/src/db/linkedRecords/index.js
+++ b/packages/server/src/db/linkedRecords/index.js
@@ -88,23 +88,24 @@ exports.attachLinkInfo = async (instanceId, records) => {
     records = [records]
     wasArray = false
   }
+  let modelIds = [...new Set(records.map(el => el.modelId))]
   // start by getting all the link values for performance reasons
-  let responses = await Promise.all(
-    records.map(record =>
-      getLinkDocuments({
-        instanceId,
-        modelId: record.modelId,
-        recordId: record._id,
-        includeDocs: IncludeDocs.EXCLUDE,
-      })
+  let responses = [].concat.apply(
+    [],
+    await Promise.all(
+      modelIds.map(modelId =>
+        getLinkDocuments({
+          instanceId,
+          modelId: modelId,
+          includeDocs: IncludeDocs.EXCLUDE,
+        })
+      )
     )
   )
-  // can just use an index to access responses, order maintained
-  let index = 0
   // now iterate through the records and all field information
   for (let record of records) {
     // get all links for record, ignore fieldName for now
-    const linkVals = responses[index++]
+    const linkVals = responses.filter(el => el.thisId === record._id)
     for (let linkVal of linkVals) {
       // work out which link pertains to this record
       if (!(record[linkVal.fieldName] instanceof Array)) {
diff --git a/packages/server/src/db/linkedRecords/linkUtils.js b/packages/server/src/db/linkedRecords/linkUtils.js
index 7680a2603f..f5fe1f6786 100644
--- a/packages/server/src/db/linkedRecords/linkUtils.js
+++ b/packages/server/src/db/linkedRecords/linkUtils.js
@@ -27,10 +27,12 @@ exports.createLinkView = async instanceId => {
         let doc2 = doc.doc2
         emit([doc1.modelId, doc1.recordId], {
           id: doc2.recordId,
+          thisId: doc1.recordId,
           fieldName: doc1.fieldName,
         })
         emit([doc2.modelId, doc2.recordId], {
           id: doc1.recordId,
+          thisId: doc2.recordId,
           fieldName: doc2.fieldName,
         })
       }

From 03584cacb22ded7ed0c4c0d957937a22350fe95a Mon Sep 17 00:00:00 2001
From: mike12345567 <me@michaeldrury.co.uk>
Date: Mon, 12 Oct 2020 10:28:53 +0100
Subject: [PATCH 2/2] Using lodash flatten rather than pure JS.

---
 packages/server/src/db/linkedRecords/index.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/server/src/db/linkedRecords/index.js b/packages/server/src/db/linkedRecords/index.js
index 842900f815..ba93f3d2e8 100644
--- a/packages/server/src/db/linkedRecords/index.js
+++ b/packages/server/src/db/linkedRecords/index.js
@@ -1,5 +1,6 @@
 const LinkController = require("./LinkController")
 const { IncludeDocs, getLinkDocuments, createLinkView } = require("./linkUtils")
+const _ = require("lodash")
 
 /**
  * This functionality makes sure that when records with links are created, updated or deleted they are processed
@@ -90,8 +91,7 @@ exports.attachLinkInfo = async (instanceId, records) => {
   }
   let modelIds = [...new Set(records.map(el => el.modelId))]
   // start by getting all the link values for performance reasons
-  let responses = [].concat.apply(
-    [],
+  let responses = _.flatten(
     await Promise.all(
       modelIds.map(modelId =>
         getLinkDocuments({