fix: performance issue with ordering

@mattwr18 @aonomike
You must never `ORDER BY` a property with a `@cypher` directive. Reason:
The order by performance will be terribly poor.

See my issue:
https://github.com/neo4j-graphql/neo4j-graphql-js/issues/239
And my PR:
https://github.com/neo4j-graphql/neo4j-graphql-js/pull/247

backend/src/schema/resolvers/posts.js

@@ -234,6 +234,7 @@ export default {
         const deletePreviousRelationsResponse = await transaction.run(
           `
           MATCH (:User)-[previousRelations:PINNED]->(post:Post)
+          REMOVE post.pinned
           DELETE previousRelations
           RETURN post
         `,
@@ -248,6 +249,7 @@ export default {
             MATCH (user:User {id: $userId}) WHERE user.role = 'admin'
             MATCH (post:Post {id: $params.id})
             MERGE (user)-[pinned:PINNED {createdAt: toString(datetime())}]->(post)
+            SET post.pinned = true
             RETURN post, pinned.createdAt as pinnedAt
          `,
           { userId, params },
@@ -276,6 +278,7 @@ export default {
         const unpinPostTransactionResponse = await transaction.run(
           `
           MATCH (:User)-[previousRelations:PINNED]->(post:Post {id: $params.id})
+          REMOVE post.pinned
           DELETE previousRelations
           RETURN post
         `,
@@ -293,7 +296,7 @@ export default {
   },
   Post: {
     ...Resolver('Post', {
-      undefinedToNull: ['activityId', 'objectId', 'image', 'language', 'pinnedAt'],
+      undefinedToNull: ['activityId', 'objectId', 'image', 'language', 'pinnedAt', 'pinned'],
       hasMany: {
         tags: '-[:TAGGED]->(related:Tag)',
         categories: '-[:CATEGORIZED]->(related:Category)',

backend/src/schema/resolvers/posts.spec.js

@@ -582,6 +582,7 @@ describe('UpdatePost', () => {
           createdAt
           updatedAt
           pinnedAt
+          pinned
         }
       }
     `
@@ -599,7 +600,7 @@ describe('UpdatePost', () => {
       })
     })
 
-    describe('users cannot pin posts', () => {
+    describe('ordinary users', () => {
       it('throws authorization error', async () => {
         await expect(mutate({ mutation: pinPostMutation, variables })).resolves.toMatchObject({
           errors: [{ message: 'Not Authorised!' }],
@@ -608,7 +609,7 @@ describe('UpdatePost', () => {
       })
     })
 
-    describe('moderators cannot pin posts', () => {
+    describe('moderators', () => {
       let moderator
       beforeEach(async () => {
         moderator = await user.update({ role: 'moderator', updatedAt: new Date().toISOString() })
@@ -623,7 +624,7 @@ describe('UpdatePost', () => {
       })
     })
 
-    describe('admin can pin posts', () => {
+    describe('admins', () => {
       let admin
       beforeEach(async () => {
         admin = await user.update({
@@ -634,16 +635,16 @@ describe('UpdatePost', () => {
         authenticatedUser = await admin.toJson()
       })
 
-      describe('post created by them', () => {
+      describe('are allowed to pin posts', () => {
         beforeEach(async () => {
           await factory.create('Post', {
             id: 'created-and-pinned-by-same-admin',
             author: admin,
           })
+          variables = { ...variables, id: 'created-and-pinned-by-same-admin' }
         })
 
         it('responds with the updated Post', async () => {
-          variables = { ...variables, id: 'created-and-pinned-by-same-admin' }
           const expected = {
             data: {
               pinPost: {
@@ -667,7 +668,6 @@ describe('UpdatePost', () => {
         })
 
         it('sets createdAt date for PINNED', async () => {
-          variables = { ...variables, id: 'created-and-pinned-by-same-admin' }
           const expected = {
             data: {
               pinPost: {
@@ -681,6 +681,17 @@ describe('UpdatePost', () => {
             expected,
           )
         })
+
+        it('sets redundant `pinned` property for performant ordering', async () => {
+          variables = { ...variables, id: 'created-and-pinned-by-same-admin' }
+          const expected = {
+            data: { pinPost: { pinned: true } },
+            errors: undefined,
+          }
+          await expect(mutate({ mutation: pinPostMutation, variables })).resolves.toMatchObject(
+            expected,
+          )
+        })
       })
 
       describe('post created by another admin', () => {
@@ -748,7 +759,7 @@ describe('UpdatePost', () => {
         })
       })
 
-      describe('removes other pinned post', () => {
+      describe('pinned post already exists', () => {
         let pinnedPost
         beforeEach(async () => {
           await factory.create('Post', {
@@ -756,42 +767,41 @@ describe('UpdatePost', () => {
             author: admin,
           })
           await mutate({ mutation: pinPostMutation, variables })
+        })
+
+        it('removes previous `pinned` attribute', async () => {
+          const cypher = 'MATCH (post:Post) WHERE post.pinned IS NOT NULL RETURN post'
+          pinnedPost = await neode.cypher(cypher)
+          expect(pinnedPost.records).toHaveLength(1)
+          variables = { ...variables, id: 'only-pinned-post' }
+          await mutate({ mutation: pinPostMutation, variables })
+          pinnedPost = await neode.cypher(cypher)
+          expect(pinnedPost.records).toHaveLength(1)
+        })
+
+        it('removes previous PINNED relationship', async () => {
           variables = { ...variables, id: 'only-pinned-post' }
           await mutate({ mutation: pinPostMutation, variables })
           pinnedPost = await neode.cypher(
             `MATCH (:User)-[pinned:PINNED]->(post:Post) RETURN post, pinned`,
           )
-        })
-
-        it('leaves only one pinned post at a time', async () => {
           expect(pinnedPost.records).toHaveLength(1)
         })
       })
 
       describe('PostOrdering', () => {
-        let pinnedPost, postCreatedAfterPinnedPost, newDate, timeInPast, admin
+        let pinnedPost, admin
         beforeEach(async () => {
-          ;[pinnedPost, postCreatedAfterPinnedPost] = await Promise.all([
+          ;[pinnedPost] = await Promise.all([
             neode.create('Post', {
               id: 'im-a-pinned-post',
+              pinned: true,
             }),
             neode.create('Post', {
               id: 'i-was-created-after-pinned-post',
+              createdAt: '2019-10-22T17:26:29.070Z', // this should always be 3rd
             }),
           ])
-          newDate = new Date()
-          timeInPast = newDate.getDate() - 3
-          newDate.setDate(timeInPast)
-          await pinnedPost.update({
-            createdAt: newDate.toISOString(),
-            updatedAt: new Date().toISOString(),
-          })
-          timeInPast = newDate.getDate() + 1
-          newDate.setDate(timeInPast)
-          await postCreatedAfterPinnedPost.update({
-            createdAt: newDate.toISOString(),
-            updatedAt: new Date().toISOString(),
-          })
           admin = await user.update({
             role: 'admin',
             name: 'Admin',
@@ -827,7 +837,7 @@ describe('UpdatePost', () => {
               ],
             },
           }
-          variables = { orderBy: ['pinnedAt_asc', 'createdAt_desc'] }
+          variables = { orderBy: ['pinned_desc', 'createdAt_desc'] }
           await expect(query({ query: postOrderingQuery, variables })).resolves.toMatchObject(
             expected,
           )
@@ -854,6 +864,8 @@ describe('UpdatePost', () => {
           }
           createdAt
           updatedAt
+          pinned
+          pinnedAt
         }
       }
     `
@@ -906,16 +918,17 @@ describe('UpdatePost', () => {
         })
         authenticatedUser = await admin.toJson()
         await admin.relateTo(pinnedPost, 'pinned', { createdAt: new Date().toISOString() })
+        variables = { ...variables, id: 'post-to-be-unpinned' }
       })
 
       it('responds with the unpinned Post', async () => {
         authenticatedUser = await admin.toJson()
-        variables = { ...variables, id: 'post-to-be-unpinned' }
         const expected = {
           data: {
             unpinPost: {
               id: 'post-to-be-unpinned',
               pinnedBy: null,
+              pinnedAt: null,
             },
           },
           errors: undefined,
@@ -925,6 +938,21 @@ describe('UpdatePost', () => {
           expected,
         )
       })
+
+      it('unsets `pinned` property', async () => {
+        const expected = {
+          data: {
+            unpinPost: {
+              id: 'post-to-be-unpinned',
+              pinned: null,
+            },
+          },
+          errors: undefined,
+        }
+        await expect(mutate({ mutation: unpinPostMutation, variables })).resolves.toMatchObject(
+          expected,
+        )
+      })
     })
   })
 })

backend/src/schema/types/type/Post.gql

@@ -1,3 +1,37 @@
+enum _PostOrdering {
+  id_asc
+  id_desc
+  activityId_asc
+  activityId_desc
+  objectId_asc
+  objectId_desc
+  title_asc
+  title_desc
+  slug_asc
+  slug_desc
+  content_asc
+  content_desc
+  contentExcerpt_asc
+  contentExcerpt_desc
+  image_asc
+  image_desc
+  visibility_asc
+  visibility_desc
+  deleted_asc
+  deleted_desc
+  disabled_asc
+  disabled_desc
+  createdAt_asc
+  createdAt_desc
+  updatedAt_asc
+  updatedAt_desc
+  language_asc
+  language_desc
+  pinned_asc
+  pinned_desc
+}
+
+
 type Post {
   id: ID!
   activityId: String
@@ -12,6 +46,7 @@ type Post {
   visibility: Visibility
   deleted: Boolean
   disabled: Boolean
+  pinned: Boolean
   disabledBy: User @relation(name: "DISABLED", direction: "IN")
   createdAt: String
   updatedAt: String

webapp/pages/index.vue

@@ -205,7 +205,7 @@ export default {
         return {
           filter: this.finalFilters,
           first: this.pageSize,
-          orderBy: ['pinnedAt_asc', this.orderBy],
+          orderBy: ['pinned_asc', this.orderBy],
           offset: 0,
         }
       },