diff --git a/app/assets/javascripts/blob/line_highlighter.js b/app/assets/javascripts/blob/line_highlighter.js
index a1f59aa1b54..a8932f8c73b 100644
--- a/app/assets/javascripts/blob/line_highlighter.js
+++ b/app/assets/javascripts/blob/line_highlighter.js
@@ -37,6 +37,7 @@ const LineHighlighter = function (options = {}) {
   options.fileHolderSelector = options.fileHolderSelector || '.file-holder';
   options.scrollFileHolder = options.scrollFileHolder || false;
   options.hash = options.hash || window.location.hash;
+  options.scrollBehavior = options.scrollBehavior || 'smooth';
 
   this.options = options;
   this._hash = options.hash;
@@ -74,6 +75,7 @@ LineHighlighter.prototype.highlightHash = function (newHash) {
         // Scroll to the first highlighted line on initial load
         // Add an offset of -100 for some context
         offset: -100,
+        behavior: this.options.scrollBehavior,
       });
     }
   }
diff --git a/app/assets/javascripts/invite_members/components/group_select.vue b/app/assets/javascripts/invite_members/components/group_select.vue
index 04a8ec3400f..fc14b2eba6a 100644
--- a/app/assets/javascripts/invite_members/components/group_select.vue
+++ b/app/assets/javascripts/invite_members/components/group_select.vue
@@ -24,10 +24,6 @@ export default {
     prop: 'selectedGroup',
   },
   props: {
-    accessLevels: {
-      type: Object,
-      required: true,
-    },
     groupsFilter: {
       type: String,
       required: false,
@@ -58,13 +54,6 @@ export default {
     isFetchResultEmpty() {
       return this.groups.length === 0;
     },
-    defaultFetchOptions() {
-      return {
-        exclude_internal: true,
-        active: true,
-        min_access_level: this.accessLevels.Guest,
-      };
-    },
   },
   watch: {
     searchTerm() {
@@ -107,9 +96,13 @@ export default {
     fetchGroups() {
       switch (this.groupsFilter) {
         case GROUP_FILTERS.DESCENDANT_GROUPS:
-          return getDescendentGroups(this.parentGroupId, this.searchTerm, this.defaultFetchOptions);
+          return getDescendentGroups(
+            this.parentGroupId,
+            this.searchTerm,
+            this.$options.defaultFetchOptions,
+          );
         default:
-          return getGroups(this.searchTerm, this.defaultFetchOptions);
+          return getGroups(this.searchTerm, this.$options.defaultFetchOptions);
       }
     },
   },
@@ -118,6 +111,10 @@ export default {
     searchPlaceholder: s__('GroupSelect|Search groups'),
     emptySearchResult: s__('GroupSelect|No matching results'),
   },
+  defaultFetchOptions: {
+    exclude_internal: true,
+    active: true,
+  },
 };
 </script>
 <template>
diff --git a/app/assets/javascripts/invite_members/components/invite_groups_modal.vue b/app/assets/javascripts/invite_members/components/invite_groups_modal.vue
index f266d978ffa..f145c00f4fd 100644
--- a/app/assets/javascripts/invite_members/components/invite_groups_modal.vue
+++ b/app/assets/javascripts/invite_members/components/invite_groups_modal.vue
@@ -155,7 +155,6 @@ export default {
     <template #select>
       <group-select
         v-model="groupToBeSharedWith"
-        :access-levels="accessLevels"
         :groups-filter="groupSelectFilter"
         :parent-group-id="groupSelectParentId"
         :invalid-groups="invalidGroups"
diff --git a/app/assets/javascripts/vue_shared/components/line_numbers.vue b/app/assets/javascripts/vue_shared/components/line_numbers.vue
deleted file mode 100644
index 11caf3be00a..00000000000
--- a/app/assets/javascripts/vue_shared/components/line_numbers.vue
+++ /dev/null
@@ -1,31 +0,0 @@
-<script>
-import { GlIcon, GlLink } from '@gitlab/ui';
-
-export default {
-  components: {
-    GlIcon,
-    GlLink,
-  },
-  props: {
-    lines: {
-      type: Number,
-      required: true,
-    },
-  },
-};
-</script>
-<template>
-  <div class="line-numbers">
-    <gl-link
-      v-for="line in lines"
-      :id="`L${line}`"
-      :key="line"
-      class="diff-line-num gl-shadow-none!"
-      :to="`#LC${line}`"
-      :data-line-number="line"
-    >
-      <gl-icon :size="12" name="link" />
-      {{ line }}
-    </gl-link>
-  </div>
-</template>
diff --git a/app/assets/javascripts/vue_shared/components/source_viewer/components/chunk.vue b/app/assets/javascripts/vue_shared/components/source_viewer/components/chunk.vue
new file mode 100644
index 00000000000..db0ee0cf00e
--- /dev/null
+++ b/app/assets/javascripts/vue_shared/components/source_viewer/components/chunk.vue
@@ -0,0 +1,103 @@
+<script>
+import { GlIntersectionObserver, GlSafeHtmlDirective } from '@gitlab/ui';
+import ChunkLine from './chunk_line.vue';
+
+/*
+ * We only highlight the chunk that is currently visible to the user.
+ * By making use of the Intersection Observer API we can determine when a chunk becomes visible and highlight it accordingly.
+ *
+ * Content that is not visible to the user (i.e. not highlighted) do not need to look nice,
+ * so by making text transparent and rendering raw (non-highlighted) text,
+ * the browser spends less resources on painting content that is not immediately relevant.
+ *
+ * Why use transparent text as opposed to hiding content entirely?
+ * 1. If content is hidden entirely, native find text (⌘ + F) won't work.
+ * 2. When URL contains line numbers, the browser needs to be able to jump to the correct line.
+ */
+export default {
+  components: {
+    ChunkLine,
+    GlIntersectionObserver,
+  },
+  directives: {
+    SafeHtml: GlSafeHtmlDirective,
+  },
+  props: {
+    chunkIndex: {
+      type: Number,
+      required: false,
+      default: 0,
+    },
+    isHighlighted: {
+      type: Boolean,
+      required: true,
+    },
+    content: {
+      type: String,
+      required: true,
+    },
+    startingFrom: {
+      type: Number,
+      required: false,
+      default: 0,
+    },
+    totalLines: {
+      type: Number,
+      required: false,
+      default: 0,
+    },
+    language: {
+      type: String,
+      required: false,
+      default: null,
+    },
+  },
+  computed: {
+    lines() {
+      return this.content.split('\n');
+    },
+  },
+  methods: {
+    handleChunkAppear() {
+      if (!this.isHighlighted) {
+        this.$emit('appear', this.chunkIndex);
+      }
+    },
+  },
+};
+</script>
+<template>
+  <div>
+    <gl-intersection-observer @appear="handleChunkAppear">
+      <div v-if="isHighlighted">
+        <chunk-line
+          v-for="(line, index) in lines"
+          :key="index"
+          :number="startingFrom + index + 1"
+          :content="line"
+          :language="language"
+        />
+      </div>
+      <div v-else class="gl-display-flex">
+        <div class="gl-display-flex gl-flex-direction-column">
+          <a
+            v-for="(n, index) in totalLines"
+            :id="`L${startingFrom + index + 1}`"
+            :key="index"
+            class="gl-ml-5 gl-text-transparent"
+            :href="`#L${startingFrom + index + 1}`"
+            :data-line-number="startingFrom + index + 1"
+            data-testid="line-number"
+          >
+            {{ startingFrom + index + 1 }}
+          </a>
+        </div>
+        <div
+          v-safe-html="content"
+          class="gl-white-space-pre-wrap! gl-text-transparent"
+          data-testid="content"
+        ></div>
+      </div>
+    </gl-intersection-observer>
+  </div>
+</template>
diff --git a/app/assets/javascripts/vue_shared/components/source_viewer/components/chunk_line.vue b/app/assets/javascripts/vue_shared/components/source_viewer/components/chunk_line.vue
new file mode 100644
index 00000000000..ab989ae6f9e
--- /dev/null
+++ b/app/assets/javascripts/vue_shared/components/source_viewer/components/chunk_line.vue
@@ -0,0 +1,44 @@
+<script>
+import { GlLink, GlSafeHtmlDirective } from '@gitlab/ui';
+
+export default {
+  components: {
+    GlLink,
+  },
+  directives: {
+    SafeHtml: GlSafeHtmlDirective,
+  },
+  props: {
+    number: {
+      type: Number,
+      required: true,
+    },
+    content: {
+      type: String,
+      required: true,
+    },
+    language: {
+      type: String,
+      required: true,
+    },
+  },
+};
+</script>
+<template>
+  <div class="gl-display-flex">
+    <div class="line-numbers gl-pt-0! gl-pb-0! gl-absolute gl-z-index-3">
+      <gl-link
+        :id="`L${number}`"
+        class="file-line-num diff-line-num gl-user-select-none"
+        :to="`#L${number}`"
+        :data-line-number="number"
+      >
+        {{ number }}
+      </gl-link>
+    </div>
+
+    <pre
+      class="code highlight gl-p-0! gl-w-full gl-overflow-visible! gl-ml-11!"
+    ><code><span :id="`LC${number}`" v-safe-html="content" :lang="language" class="line" data-testid="content"></span></code></pre>
+  </div>
+</template>
diff --git a/app/assets/javascripts/vue_shared/components/source_viewer/constants.js b/app/assets/javascripts/vue_shared/components/source_viewer/constants.js
index 9efe0147c37..b5ce214e577 100644
--- a/app/assets/javascripts/vue_shared/components/source_viewer/constants.js
+++ b/app/assets/javascripts/vue_shared/components/source_viewer/constants.js
@@ -109,3 +109,5 @@ export const ROUGE_TO_HLJS_LANGUAGE_MAP = {
   xquery: 'xquery',
   yaml: 'yaml',
 };
+
+export const LINES_PER_CHUNK = 70;
diff --git a/app/assets/javascripts/vue_shared/components/source_viewer/source_viewer.vue b/app/assets/javascripts/vue_shared/components/source_viewer/source_viewer.vue
index 4a78cbacec0..15411e8d17e 100644
--- a/app/assets/javascripts/vue_shared/components/source_viewer/source_viewer.vue
+++ b/app/assets/javascripts/vue_shared/components/source_viewer/source_viewer.vue
@@ -1,16 +1,21 @@
 <script>
 import { GlSafeHtmlDirective, GlLoadingIcon } from '@gitlab/ui';
-import LineNumbers from '~/vue_shared/components/line_numbers.vue';
-import { sanitize } from '~/lib/dompurify';
-import { ROUGE_TO_HLJS_LANGUAGE_MAP } from './constants';
-import { wrapLines } from './utils';
-
-const LINE_SELECT_CLASS_NAME = 'hll';
+import LineHighlighter from '~/blob/line_highlighter';
+import { ROUGE_TO_HLJS_LANGUAGE_MAP, LINES_PER_CHUNK } from './constants';
+import Chunk from './components/chunk.vue';
 
+/*
+ * This component is optimized to handle source code with many lines of code by splitting source code into chunks of 70 lines of code,
+ * we highlight and display the 1st chunk (L1-70) to the user as quickly as possible.
+ *
+ * The rest of the lines (L71+) is rendered once the browser goes into an idle state (requestIdleCallback).
+ * Each chunk is self-contained, this ensures when for example the width of a container on line 1000 changes,
+ * it does not trigger a repaint on a parent element that wraps all 1000 lines.
+ */
 export default {
   components: {
-    LineNumbers,
     GlLoadingIcon,
+    Chunk,
   },
   directives: {
     SafeHtml: GlSafeHtmlDirective,
@@ -27,46 +32,92 @@ export default {
       content: this.blob.rawTextBlob,
       language: ROUGE_TO_HLJS_LANGUAGE_MAP[this.blob.language],
       hljs: null,
+      firstChunk: null,
+      chunks: {},
+      isLoading: true,
+      isLineSelected: false,
+      lineHighlighter: null,
     };
   },
   computed: {
+    splitContent() {
+      return this.content.split('\n');
+    },
     lineNumbers() {
-      return this.content.split('\n').length;
-    },
-    highlightedContent() {
-      let highlightedContent;
-      let { language } = this;
-
-      if (this.hljs) {
-        if (!language) {
-          const hljsHighlightAuto = this.hljs.highlightAuto(this.content);
-
-          highlightedContent = hljsHighlightAuto.value;
-          language = hljsHighlightAuto.language;
-        } else if (this.languageDefinition) {
-          highlightedContent = this.hljs.highlight(this.content, { language: this.language }).value;
-        }
-      }
-
-      return wrapLines(highlightedContent, language);
+      return this.splitContent.length;
     },
   },
-  watch: {
-    highlightedContent() {
-      this.$nextTick(() => this.selectLine());
-    },
-    $route() {
-      this.selectLine();
-    },
-  },
-  async mounted() {
+  async created() {
+    this.generateFirstChunk();
     this.hljs = await this.loadHighlightJS();
 
     if (this.language) {
       this.languageDefinition = await this.loadLanguage();
     }
+
+    // Highlight the first chunk as soon as highlight.js is available
+    this.highlightChunk(null, true);
+
+    window.requestIdleCallback(async () => {
+      // Generate the remaining chunks once the browser idles to ensure the browser resources are spent on the most important things first
+      this.generateRemainingChunks();
+      this.isLoading = false;
+      await this.$nextTick();
+      this.lineHighlighter = new LineHighlighter({ scrollBehavior: 'auto' });
+    });
   },
   methods: {
+    generateFirstChunk() {
+      const lines = this.splitContent.splice(0, LINES_PER_CHUNK);
+      this.firstChunk = this.createChunk(lines);
+    },
+    generateRemainingChunks() {
+      const result = {};
+      for (let i = 0; i < this.splitContent.length; i += LINES_PER_CHUNK) {
+        const chunkIndex = Math.floor(i / LINES_PER_CHUNK);
+        const lines = this.splitContent.slice(i, i + LINES_PER_CHUNK);
+        result[chunkIndex] = this.createChunk(lines, i + LINES_PER_CHUNK);
+      }
+
+      this.chunks = result;
+    },
+    createChunk(lines, startingFrom = 0) {
+      return {
+        content: lines.join('\n'),
+        startingFrom,
+        totalLines: lines.length,
+        language: this.language,
+        isHighlighted: false,
+      };
+    },
+    highlightChunk(index, isFirstChunk) {
+      const chunk = isFirstChunk ? this.firstChunk : this.chunks[index];
+
+      if (chunk.isHighlighted) {
+        return;
+      }
+
+      const { highlightedContent, language } = this.highlight(chunk.content, this.language);
+
+      Object.assign(chunk, { language, content: highlightedContent, isHighlighted: true });
+
+      this.selectLine();
+    },
+    highlight(content, language) {
+      let detectedLanguage = language;
+      let highlightedContent;
+      if (this.hljs) {
+        if (!detectedLanguage) {
+          const hljsHighlightAuto = this.hljs.highlightAuto(content);
+          highlightedContent = hljsHighlightAuto.value;
+          detectedLanguage = hljsHighlightAuto.language;
+        } else if (this.languageDefinition) {
+          highlightedContent = this.hljs.highlight(content, { language: this.language }).value;
+        }
+      }
+
+      return { highlightedContent, language: detectedLanguage };
+    },
     loadHighlightJS() {
       // If no language can be mapped to highlight.js we load all common languages else we load only the core (smallest footprint)
       return !this.language ? import('highlight.js/lib/common') : import('highlight.js/lib/core');
@@ -83,21 +134,14 @@ export default {
 
       return languageDefinition;
     },
-    selectLine() {
-      const hash = sanitize(this.$route.hash);
-      const lineToSelect = hash && this.$el.querySelector(hash);
-
-      if (!lineToSelect) {
+    async selectLine() {
+      if (this.isLineSelected || !this.lineHighlighter) {
         return;
       }
 
-      if (this.$options.currentlySelectedLine) {
-        this.$options.currentlySelectedLine.classList.remove(LINE_SELECT_CLASS_NAME);
-      }
-
-      lineToSelect.classList.add(LINE_SELECT_CLASS_NAME);
-      this.$options.currentlySelectedLine = lineToSelect;
-      lineToSelect.scrollIntoView({ behavior: 'smooth', block: 'center' });
+      this.isLineSelected = true;
+      await this.$nextTick();
+      this.lineHighlighter.highlightHash(this.$route.hash);
     },
   },
   userColorScheme: window.gon.user_color_scheme,
@@ -105,16 +149,35 @@ export default {
 };
 </script>
 <template>
-  <gl-loading-icon v-if="!highlightedContent" size="sm" class="gl-my-5" />
   <div
-    v-else
-    class="file-content code js-syntax-highlight blob-content gl-display-flex"
+    class="file-content code js-syntax-highlight blob-content gl-display-flex gl-flex-direction-column gl-overflow-auto"
     :class="$options.userColorScheme"
     data-type="simple"
     data-qa-selector="blob_viewer_file_content"
   >
-    <line-numbers :lines="lineNumbers" />
-    <pre class="code highlight gl-pb-0!"><code v-safe-html="highlightedContent"></code>
-    </pre>
+    <chunk
+      v-if="firstChunk"
+      :lines="firstChunk.lines"
+      :total-lines="firstChunk.totalLines"
+      :content="firstChunk.content"
+      :starting-from="firstChunk.startingFrom"
+      :is-highlighted="firstChunk.isHighlighted"
+      :language="firstChunk.language"
+    />
+
+    <gl-loading-icon v-if="isLoading" size="sm" class="gl-my-5" />
+    <chunk
+      v-for="(chunk, key, index) in chunks"
+      v-else
+      :key="key"
+      :lines="chunk.lines"
+      :content="chunk.content"
+      :total-lines="chunk.totalLines"
+      :starting-from="chunk.startingFrom"
+      :is-highlighted="chunk.isHighlighted"
+      :chunk-index="index"
+      :language="chunk.language"
+      @appear="highlightChunk"
+    />
   </div>
 </template>
diff --git a/app/assets/javascripts/vue_shared/components/source_viewer/utils.js b/app/assets/javascripts/vue_shared/components/source_viewer/utils.js
deleted file mode 100644
index d726a8a55ff..00000000000
--- a/app/assets/javascripts/vue_shared/components/source_viewer/utils.js
+++ /dev/null
@@ -1,28 +0,0 @@
-export const wrapLines = (content, language) => {
-  const isValidLanguage = /^[a-z\d\-_]+$/.test(language); // To prevent the possibility of a vulnerability we only allow languages that contain alphanumeric characters ([a-z\d), dashes (-) or underscores (_).
-
-  return (
-    content &&
-    content
-      .split('\n')
-      .map((line, i) => {
-        let formattedLine;
-        const attributes = `id="LC${i + 1}" lang="${isValidLanguage ? language : ''}"`;
-
-        if (line.includes('<span class="hljs') && !line.includes('</span>')) {
-          /**
-           * In some cases highlight.js will wrap multiple lines in a span, in these cases we want to append the line number to the existing span
-           *
-           * example (before):  <span class="hljs-code">```bash
-           * example (after):   <span id="LC67" class="hljs-code">```bash
-           */
-          formattedLine = line.replace(/(?=class="hljs)/, `${attributes} `);
-        } else {
-          formattedLine = `<span ${attributes} class="line">${line}</span>`;
-        }
-
-        return formattedLine;
-      })
-      .join('\n')
-  );
-};
diff --git a/db/migrate/20220120160625_remove_temp_index_on_id_from_vulnerability_occurrences.rb b/db/migrate/20220120160625_remove_temp_index_on_id_from_vulnerability_occurrences.rb
new file mode 100644
index 00000000000..747cabcd865
--- /dev/null
+++ b/db/migrate/20220120160625_remove_temp_index_on_id_from_vulnerability_occurrences.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class RemoveTempIndexOnIdFromVulnerabilityOccurrences < Gitlab::Database::Migration[1.0]
+  INDEX_NAME = 'tmp_idx_vulnerability_occurrences_on_id_where_report_type_7_99'
+
+  disable_ddl_transaction!
+
+  def up
+    remove_concurrent_index_by_name :vulnerability_occurrences, name: INDEX_NAME
+  end
+
+  def down
+    add_concurrent_index :vulnerability_occurrences, :id, where: 'report_type IN (7, 99)', name: INDEX_NAME
+  end
+end
diff --git a/db/schema_migrations/20220120160625 b/db/schema_migrations/20220120160625
new file mode 100644
index 00000000000..287e364d331
--- /dev/null
+++ b/db/schema_migrations/20220120160625
@@ -0,0 +1 @@
+92485ceb25d5733efe9a35a5bd64c9f33253bb10f815590518c6fc8d1c9e5f39
\ No newline at end of file
diff --git a/db/structure.sql b/db/structure.sql
index 992319411b1..2ea0087c65a 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -29567,8 +29567,6 @@ CREATE INDEX tmp_gitlab_subscriptions_max_seats_used_migration ON gitlab_subscri
 
 CREATE INDEX tmp_gitlab_subscriptions_max_seats_used_migration_2 ON gitlab_subscriptions USING btree (id) WHERE ((start_date < '2021-08-02'::date) AND (max_seats_used <> 0) AND (max_seats_used > seats_in_use) AND (max_seats_used > seats));
 
-CREATE INDEX tmp_idx_vulnerability_occurrences_on_id_where_report_type_7_99 ON vulnerability_occurrences USING btree (id) WHERE (report_type = ANY (ARRAY[7, 99]));
-
 CREATE INDEX tmp_index_ci_job_artifacts_on_id_where_trace_and_expire_at ON ci_job_artifacts USING btree (id) WHERE ((file_type = 3) AND (expire_at = ANY (ARRAY['2021-04-22 00:00:00+00'::timestamp with time zone, '2021-05-22 00:00:00+00'::timestamp with time zone, '2021-06-22 00:00:00+00'::timestamp with time zone, '2022-01-22 00:00:00+00'::timestamp with time zone, '2022-02-22 00:00:00+00'::timestamp with time zone, '2022-03-22 00:00:00+00'::timestamp with time zone, '2022-04-22 00:00:00+00'::timestamp with time zone])));
 
 CREATE INDEX tmp_index_container_repositories_on_id_migration_state ON container_repositories USING btree (id, migration_state);
diff --git a/doc/administration/gitaly/index.md b/doc/administration/gitaly/index.md
index f88a1aa2b4d..829ffd81d30 100644
--- a/doc/administration/gitaly/index.md
+++ b/doc/administration/gitaly/index.md
@@ -43,23 +43,26 @@ repository storage is either:
   - Read requests are distributed between multiple Gitaly nodes, which can improve performance.
   - Write requests are broadcast to repository replicas.
 
-## Guidance regarding Gitaly Cluster
+## Before deploying Gitaly Cluster
 
-Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please review existing technical limitations and considerations prior to deploying Gitaly Cluster.
+Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management.
+Before deploying Gitaly Cluster, please review:
 
-- [Known issues](#known-issues)
+- Existing [known issues](#known-issues).
 - [Snapshot limitations](#snapshot-backup-and-recovery-limitations).
+- [Configuration guidance](configure_gitaly.md) and [Repository storage options](../repository_storage_paths.md) to make
+  sure that Gitaly Cluster is the best setup for you.
 
-Please also review the [configuration guidance](configure_gitaly.md) and [Repository storage options](../repository_storage_paths.md) to make sure that Gitaly Cluster is the best set-up for you. Finally, refer to the following guidance:
+If you have:
 
-- If you have not yet migrated to Gitaly Cluster and want to continue using NFS, remain on the
-  service you are using. NFS is supported in 14.x releases.
-- If you have not yet migrated to Gitaly Cluster but want to migrate away from NFS, you have two options - a sharded Gitaly instance or Gitaly Cluster.
-- If you have migrated to Gitaly Cluster and the limitations and tradeoffs are not suitable for your environment, your options are:
-  1. [Migrate off Gitaly Cluster](#migrate-off-gitaly-cluster) back to your NFS solution
-  1. [Migrate off Gitaly Cluster](#migrate-off-gitaly-cluster) to NFS solution or to a sharded Gitaly instance.
+- Not yet migrated to Gitaly Cluster and want to continue using NFS, remain on the service you are using. NFS is
+  supported in 14.x releases but is [deprecated](../../update/deprecations.md#reminder-support-for-nfs-repository-storage).
+Support for storing Git repository data on NFS will end for all versions of GitLab with the release of 15.0.
+- Not yet migrated to Gitaly Cluster but want to migrate away from NFS, you have two options:
+  - A sharded Gitaly instance.
+  - Gitaly Cluster.
 
-Reach out to your Technical Account Manager or customer support if you have any questions.
+Contact your Technical Account Manager or customer support if you have any questions.
 
 ### Known issues
 
@@ -69,19 +72,20 @@ the current status of these issues, please refer to the referenced issues and ep
 | Issue                                                                                 | Summary                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | How to avoid |
 |:--------------------------------------------------------------------------------------|:------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|:--------------------------------|
 | Gitaly Cluster + Geo - Issues retrying failed syncs                             | If Gitaly Cluster is used on a Geo secondary site, repositories that have failed to sync could continue to fail when Geo tries to resync them. Recovering from this state requires assistance from support to run manual steps. Work is in-progress to update Gitaly Cluster to [identify repositories with a unique and persistent identifier](https://gitlab.com/gitlab-org/gitaly/-/issues/3485), which is expected to resolve the issue.                                                                                                                                                                                                                                          | No known solution at this time. |
-| Database inconsistencies due to repository access outside of Gitaly Cluster's control | Operations that write to the repository storage that do not go through normal Gitaly Cluster methods can cause database inconsistencies. These can include (but are not limited to) snapshot restoration for cluster node disks, node upgrades which modify files under Git control, or any other disk operation that may touch repository storage external to GitLab. The Gitaly team is actively working to provide manual commands to [reconcile the Praefect database with the repository storage](https://gitlab.com/groups/gitlab-org/-/epics/6723).  | Don't directly change repositories on any Gitaly Cluster node at this time. |
 | Praefect unable to insert data into the database due to migrations not being applied after an upgrade | If the database is not kept up to date with completed migrations, then the Praefect node is unable to perform normal operation. | Make sure the Praefect database is up and running with all migrations completed (For example: `/opt/gitlab/embedded/bin/praefect -config /var/opt/gitlab/praefect/config.toml sql-migrate-status` should show a list of all applied migrations). Consider [requesting live upgrade assistance](https://about.gitlab.com/support/scheduling-live-upgrade-assistance.html) so your upgrade plan can be reviewed by support. |
 | Restoring a Gitaly Cluster node from a snapshot in a running cluster | Because the Gitaly Cluster runs with consistent state, introducing a single node that is behind will result in the cluster not being able to reconcile the nodes data and other nodes data | Don't restore a single Gitaly Cluster node from a backup snapshot. If you must restore from backup, it's best to snapshot all Gitaly Cluster nodes at the same time and take a database dump of the Praefect database. |
 
 ### Snapshot backup and recovery limitations
 
-Gitaly Cluster does not support snapshot backups because these can cause issues where the Praefect
-database becomes out of sync with the disk storage. Because of how Praefect rebuilds the replication
-metadata of Gitaly disk information during a restore, we recommend using the
-[official backup and restore Rake tasks](../../raketasks/backup_restore.md). If you are unable to use this method, please contact customer support for restoration help.
+Gitaly Cluster does not support snapshot backups. Snapshot backups can cause issues where the Praefect database becomes
+out of sync with the disk storage. Because of how Praefect rebuilds the replication metadata of Gitaly disk information
+during a restore, we recommend using the [official backup and restore Rake tasks](../../raketasks/backup_restore.md).
 
-To track progress on work on a solution for manually re-synchronizing the Praefect database with
-disk storage, see [this epic](https://gitlab.com/groups/gitlab-org/-/epics/6575).
+If you are unable to use this method, please contact customer support for restoration help.
+
+We are tracking in [this issue](https://gitlab.com/gitlab-org/gitlab/-/issues/351383) improvements to the
+[official backup and restore Rake tasks](../../raketasks/backup_restore.md) to add support for incremental backups. For
+more information, see [this epic](https://gitlab.com/groups/gitlab-org/-/epics/2094).
 
 ### What to do if you are on Gitaly Cluster experiencing an issue or limitation
 
@@ -361,7 +365,8 @@ For more information on configuring Gitaly Cluster, see [Configure Gitaly Cluste
 
 ## Migrating to Gitaly Cluster
 
-Please see [current guidance on Gitaly Cluster](#guidance-regarding-gitaly-cluster). The basic process for migrating to Gitaly Cluster involves:
+See the [Before deploying Gitaly Cluster](#before-deploying-gitaly-cluster) section before continuing. The basic process
+for migrating to Gitaly Cluster involves:
 
 1. Create the required storage. Refer to
    [repository storage recommendations](faq.md#what-are-some-repository-storage-recommendations).
@@ -378,16 +383,14 @@ NOTE:
 GitLab requires a `default` repository storage to be configured.
 [Read more about this limitation](configure_gitaly.md#gitlab-requires-a-default-repository-storage).
 
-### Migrate off Gitaly Cluster
+## Migrate off Gitaly Cluster
 
-If you have repositories stored on a Gitaly Cluster, but you'd like to migrate
-them back to direct Gitaly storage:
+If the limitations and tradeoffs of Gitaly Cluster are found to be not suitable for your environment, you can Migrate
+off Gitaly Cluster to a sharded Gitaly instance:
 
-1. Create and configure a new
-   [Gitaly server](configure_gitaly.md#run-gitaly-on-its-own-server).
-1. [Move the repositories](../operations/moving_repositories.md#move-repositories)
-   to the newly created storage. You can move them by shard or by group, which gives you the opportunity to spread them over
-   multiple Gitaly servers.
+1. Create and configure a new [Gitaly server](configure_gitaly.md#run-gitaly-on-its-own-server).
+1. [Move the repositories](../operations/moving_repositories.md#move-repositories) to the newly created storage. You can
+   move them by shard or by group, which gives you the opportunity to spread them over multiple Gitaly servers.
 
 ## Monitor Gitaly and Gitaly Cluster
 
diff --git a/doc/administration/reference_architectures/10k_users.md b/doc/administration/reference_architectures/10k_users.md
index fcce44f62b2..f82f23cca7d 100644
--- a/doc/administration/reference_architectures/10k_users.md
+++ b/doc/administration/reference_architectures/10k_users.md
@@ -42,7 +42,7 @@ full list of reference architectures, see
 2. Can be optionally run on reputable third-party external PaaS Redis solutions. Google Memorystore and AWS Elasticache are known to work.
 3. Can be optionally run on reputable third-party load balancing services (LB PaaS). AWS ELB is known to work.
 4. Should be run on reputable third-party object storage (storage PaaS) for cloud implementations. Google Cloud Storage and AWS S3 are known to work.
-5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster). If Gitaly Sharded is desired, the same specs listed above for `Gitaly` should be used.
+5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster). If you want sharded Gitaly, use the same specs listed above for `Gitaly`.
 <!-- markdownlint-enable MD029 -->
 
 NOTE:
@@ -1157,8 +1157,8 @@ are supported and can be added if needed.
 In this configuration, every Git repository is stored on every Gitaly node in the cluster, with one being designated the primary, and failover occurs automatically if the primary node goes down.
 
 NOTE:
-Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster).
-For implementations with Gitaly Sharded, the same Gitaly specs should be used. Follow the [separate Gitaly documentation](../gitaly/configure_gitaly.md) instead of this section.
+Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster).
+For implementations with sharded Gitaly, use the same Gitaly specs. Follow the [separate Gitaly documentation](../gitaly/configure_gitaly.md) instead of this section.
 
 The recommended cluster setup includes the following components:
 
@@ -2269,7 +2269,7 @@ services where applicable):
 2. Can be optionally run on reputable third-party external PaaS Redis solutions. Google Memorystore and AWS Elasticache are known to work.
 3. Can be optionally run on reputable third-party load balancing services (LB PaaS). AWS ELB is known to work.
 4. Should be run on reputable third-party object storage (storage PaaS) for cloud implementations. Google Cloud Storage and AWS S3 are known to work.
-5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster). If Gitaly Sharded is desired, the same specs listed above for `Gitaly` should be used.
+5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster). If you want sharded Gitaly, use the same specs listed above for `Gitaly`.
 <!-- markdownlint-enable MD029 -->
 
 NOTE:
diff --git a/doc/administration/reference_architectures/25k_users.md b/doc/administration/reference_architectures/25k_users.md
index c08fe985b40..6d56f67097b 100644
--- a/doc/administration/reference_architectures/25k_users.md
+++ b/doc/administration/reference_architectures/25k_users.md
@@ -42,7 +42,7 @@ full list of reference architectures, see
 2. Can be optionally run on reputable third-party external PaaS Redis solutions. Google Memorystore and AWS Elasticache are known to work.
 3. Can be optionally run on reputable third-party load balancing services (LB PaaS). AWS ELB is known to work.
 4. Should be run on reputable third-party object storage (storage PaaS) for cloud implementations. Google Cloud Storage and AWS S3 are known to work.
-5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster). If Gitaly Sharded is desired, the same specs listed above for `Gitaly` should be used.
+5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster). If you want sharded Gitaly, use the same specs listed above for `Gitaly`.
 <!-- markdownlint-enable MD029 -->
 
 NOTE:
@@ -1163,8 +1163,8 @@ fault tolerant solution for storing Git repositories.
 In this configuration, every Git repository is stored on every Gitaly node in the cluster, with one being designated the primary, and failover occurs automatically if the primary node goes down.
 
 NOTE:
-Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster).
-For implementations with Gitaly Sharded, the same Gitaly specs should be used. Follow the [separate Gitaly documentation](../gitaly/configure_gitaly.md) instead of this section.
+Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster).
+For implementations with sharded Gitaly, use the same Gitaly specs. Follow the [separate Gitaly documentation](../gitaly/configure_gitaly.md) instead of this section.
 
 The recommended cluster setup includes the following components:
 
@@ -2267,7 +2267,7 @@ services where applicable):
 2. Can be optionally run on reputable third-party external PaaS Redis solutions. Google Memorystore and AWS Elasticache are known to work.
 3. Can be optionally run on reputable third-party load balancing services (LB PaaS). AWS ELB is known to work.
 4. Should be run on reputable third-party object storage (storage PaaS) for cloud implementations. Google Cloud Storage and AWS S3 are known to work.
-5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster). If Gitaly Sharded is desired, the same specs listed above for `Gitaly` should be used.
+5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster). If you want sharded Gitaly, use the same specs listed above for `Gitaly`.
 <!-- markdownlint-enable MD029 -->
 
 NOTE:
diff --git a/doc/administration/reference_architectures/3k_users.md b/doc/administration/reference_architectures/3k_users.md
index 76f81e65580..ec6204c21a1 100644
--- a/doc/administration/reference_architectures/3k_users.md
+++ b/doc/administration/reference_architectures/3k_users.md
@@ -51,7 +51,7 @@ For a full list of reference architectures, see
 2. Can be optionally run on reputable third-party external PaaS Redis solutions. Google Memorystore and AWS Elasticache are known to work.
 3. Can be optionally run on reputable third-party load balancing services (LB PaaS). AWS ELB is known to work.
 4. Should be run on reputable third-party object storage (storage PaaS) for cloud implementations. Google Cloud Storage and AWS S3 are known to work.
-5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster). If Gitaly Sharded is desired, the same specs listed above for `Gitaly` should be used.
+5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster). If you want sharded Gitaly, use the same specs listed above for `Gitaly`.
 <!-- markdownlint-enable MD029 -->
 
 NOTE:
@@ -1104,8 +1104,8 @@ The following IPs will be used as an example:
 In this configuration, every Git repository is stored on every Gitaly node in the cluster, with one being designated the primary, and failover occurs automatically if the primary node goes down.
 
 NOTE:
-Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster).
-For implementations with Gitaly Sharded, the same Gitaly specs should be used. Follow the [separate Gitaly documentation](../gitaly/configure_gitaly.md) instead of this section.
+Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster).
+For implementations with sharded Gitaly, use the same Gitaly specs. Follow the [separate Gitaly documentation](../gitaly/configure_gitaly.md) instead of this section.
 
 The recommended cluster setup includes the following components:
 
@@ -2225,7 +2225,7 @@ services where applicable):
 2. Can be optionally run on reputable third-party external PaaS Redis solutions. Google Memorystore and AWS Elasticache are known to work.
 3. Can be optionally run on reputable third-party load balancing services (LB PaaS). AWS ELB is known to work.
 4. Should be run on reputable third-party object storage (storage PaaS) for cloud implementations. Google Cloud Storage and AWS S3 are known to work.
-5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster). If Gitaly Sharded is desired, the same specs listed above for `Gitaly` should be used.
+5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster). If you want sharded Gitaly, use the same specs listed above for `Gitaly`.
 <!-- markdownlint-enable MD029 -->
 
 NOTE:
diff --git a/doc/administration/reference_architectures/50k_users.md b/doc/administration/reference_architectures/50k_users.md
index dfa963d1ad0..9ff4e8e53c4 100644
--- a/doc/administration/reference_architectures/50k_users.md
+++ b/doc/administration/reference_architectures/50k_users.md
@@ -42,7 +42,7 @@ full list of reference architectures, see
 2. Can be optionally run on reputable third-party external PaaS Redis solutions. Google Memorystore and AWS Elasticache are known to work.
 3. Can be optionally run on reputable third-party load balancing services (LB PaaS). AWS ELB is known to work.
 4. Should be run on reputable third-party object storage (storage PaaS) for cloud implementations. Google Cloud Storage and AWS S3 are known to work.
-5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster). If Gitaly Sharded is desired, the same specs listed above for `Gitaly` should be used.
+5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster). If you want sharded Gitaly, use the same specs listed above for `Gitaly`.
 <!-- markdownlint-enable MD029 -->
 
 NOTE:
@@ -1170,8 +1170,8 @@ Advanced [configuration options](https://docs.gitlab.com/omnibus/settings/redis.
 In this configuration, every Git repository is stored on every Gitaly node in the cluster, with one being designated the primary, and failover occurs automatically if the primary node goes down.
 
 NOTE:
-Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster).
-For implementations with Gitaly Sharded, the same Gitaly specs should be used. Follow the [separate Gitaly documentation](../gitaly/configure_gitaly.md) instead of this section.
+Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster).
+For implementations with sharded Gitaly, use the same Gitaly specs. Follow the [separate Gitaly documentation](../gitaly/configure_gitaly.md) instead of this section.
 
 The recommended cluster setup includes the following components:
 
@@ -2283,7 +2283,7 @@ services where applicable):
 2. Can be optionally run on reputable third-party external PaaS Redis solutions. Google Memorystore and AWS Elasticache are known to work.
 3. Can be optionally run on reputable third-party load balancing services (LB PaaS). AWS ELB is known to work.
 4. Should be run on reputable third-party object storage (storage PaaS) for cloud implementations. Google Cloud Storage and AWS S3 are known to work.
-5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster). If Gitaly Sharded is desired, the same specs listed above for `Gitaly` should be used.
+5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster). If you want sharded Gitaly, use the same specs listed above for `Gitaly`.
 <!-- markdownlint-enable MD029 -->
 
 NOTE:
diff --git a/doc/administration/reference_architectures/5k_users.md b/doc/administration/reference_architectures/5k_users.md
index f2463afbf3b..50b5bbd6dc8 100644
--- a/doc/administration/reference_architectures/5k_users.md
+++ b/doc/administration/reference_architectures/5k_users.md
@@ -48,7 +48,7 @@ costly-to-operate environment by using the
 2. Can be optionally run on reputable third-party external PaaS Redis solutions. Google Memorystore and AWS Elasticache are known to work.
 3. Can be optionally run on reputable third-party load balancing services (LB PaaS). AWS ELB is known to work.
 4. Should be run on reputable third-party object storage (storage PaaS) for cloud implementations. Google Cloud Storage and AWS S3 are known to work.
-5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster). If Gitaly Sharded is desired, the same specs listed above for `Gitaly` should be used.
+5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster). If you want sharded Gitaly, use the same specs listed above for `Gitaly`.
 <!-- markdownlint-enable MD029 -->
 
 NOTE:
@@ -1101,8 +1101,8 @@ The following IPs will be used as an example:
 In this configuration, every Git repository is stored on every Gitaly node in the cluster, with one being designated the primary, and failover occurs automatically if the primary node goes down.
 
 NOTE:
-Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster).
-For implementations with Gitaly Sharded, the same Gitaly specs should be used. Follow the [separate Gitaly documentation](../gitaly/configure_gitaly.md) instead of this section.
+Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster).
+For implementations with sharded Gitaly, use the same Gitaly specs. Follow the [separate Gitaly documentation](../gitaly/configure_gitaly.md) instead of this section.
 
 The recommended cluster setup includes the following components:
 
@@ -2201,7 +2201,7 @@ services where applicable):
 2. Can be optionally run on reputable third-party external PaaS Redis solutions. Google Memorystore and AWS Elasticache are known to work.
 3. Can be optionally run on reputable third-party load balancing services (LB PaaS). AWS ELB is known to work.
 4. Should be run on reputable third-party object storage (storage PaaS) for cloud implementations. Google Cloud Storage and AWS S3 are known to work.
-5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Please [review the existing technical limitations and considerations prior to deploying Gitaly Cluster](../gitaly/index.md#guidance-regarding-gitaly-cluster). If Gitaly Sharded is desired, the same specs listed above for `Gitaly` should be used.
+5. Gitaly Cluster provides the benefits of fault tolerance, but comes with additional complexity of setup and management. Review the existing [technical limitations and considerations before deploying Gitaly Cluster](../gitaly/index.md#before-deploying-gitaly-cluster). If you want sharded Gitaly, use the same specs listed above for `Gitaly`.
 <!-- markdownlint-enable MD029 -->
 
 NOTE:
diff --git a/doc/development/database/database_lab.md b/doc/development/database/database_lab.md
new file mode 100644
index 00000000000..1c8694b113d
--- /dev/null
+++ b/doc/development/database/database_lab.md
@@ -0,0 +1,101 @@
+---
+stage: Enablement
+group: Database
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
+---
+
+# Database Lab and Postgres.ai
+
+Internal users at GitLab have access to the Database Lab Engine (DLE) and
+[postgres.ai](https://console.postgres.ai/) for testing performance of database queries
+on replicated production data. Unlike a typical read-only production replica, in the DLE you can
+also create, update, and delete rows. You can also test the performance of
+schema changes, like additional indexes or columns, in an isolated copy of production data.
+
+## Access Database Lab Engine
+
+Access to the DLE is helpful for:
+
+- Database reviewers and maintainers.
+- Engineers who work on merge requests that have large effects on databases.
+
+To access the DLE's services, you can:
+
+- Perform query testing in the `#database_lab` Slack channel, or in the Postgres.ai web console.
+  Employees access both services with their GitLab Google account. Query testing
+  provides `EXPLAIN` (analyze, buffers) plans for queries executed there.
+- Migration testing by triggering a job as a part of a merge request.
+- Direct `psql` access to DLE instead of a production replica. Available to authorized users only.
+  To request `psql` access, file an [access request](https://about.gitlab.com/handbook/business-technology/team-member-enablement/onboarding-access-requests/access-requests/#individual-or-bulk-access-request).
+
+For more assistance, use the `#database` Slack channel.
+
+NOTE:
+If you need only temporary access to a production replica, instead of a Database Lab
+clone, follow the runbook procedure for connecting to the
+[database console with Teleport](https://gitlab.com/gitlab-com/runbooks/-/blob/master/docs/Teleport/Connect_to_Database_Console_via_Teleport.md).
+This procedure is similar to [Rails console access with Teleport](https://gitlab.com/gitlab-com/runbooks/-/blob/master/docs/Teleport/Connect_to_Rails_Console_via_Teleport.md#how-to-use-teleport-to-connect-to-rails-console).
+
+### Query testing
+
+You can access Database Lab's query analysis features either:
+
+- In the `#database_lab` Slack channel. Shows everyone's commands and results, but
+  your own commands are still isolated in their own clone.
+- In [the Postgres.ai web console](https://console.postgres.ai/GitLab/joe-instances).
+  Shows only the commands you run.
+
+#### Generate query plans
+
+Query plans are an essential part of the database review process. These plans
+enable us to decide quickly if a given query can be performant on GitLab.com.
+Running the `explain` command generates an `explain` plan and a link to the Postgres.ai
+console with more query analysis. For example, running `EXPLAIN SELECT * FROM application_settings`
+does the following:
+
+1. Runs `explain (analyze, buffers) select * from application_settings;` against a database clone.
+1. Responds with timing and buffer details from the run.
+1. Provides a [detailed, shareable report on the results](https://console.postgres.ai/shared/24d543c9-893b-4ff6-8deb-a8f902f85a53).
+
+#### Making schema changes
+
+Sometimes when testing queries, a contributor may realize that the query needs an index
+or other schema change to make added queries more performant. To test the query, run the `exec` command.
+For example, running this command:
+
+```sql
+exec CREATE INDEX on application_settings USING btree (instance_administration_project_id)
+```
+
+creates the specified index on the table. You can [test queries](#generate-query-plans) leveraging
+the new index. `exec` does not return any results, only the time required to execute the query.
+
+#### Reset the clone
+
+After many changes, such as after a destructive query or an ineffective index,
+you must start over. To reset your designated clone, run `reset`.
+
+### Migration testing
+
+For information on testing migrations, review our
+[database migration testing documentation](database_migration_pipeline.md).
+
+### Access the console with `psql`
+
+Team members with [`psql` access](#access-database-lab-engine), can gain direct access
+to a clone via `psql`. Access to `psql` enables you to see data, not just metadata.
+
+To connect to a clone using `psql`:
+
+1. Create a clone from the [desired instance](https://console.postgres.ai/gitlab/instances/).
+   1. Provide a **Clone ID**: Something that uniquely identifies your clone, such as `yourname-testing-gitlabissue`.
+   1. Provide a **Database username** and **Database password**: Connects `psql` to your clone.
+   1. Select **Enable deletion protection** if you want to preserve your clone. Avoid selecting this option.
+      Clones are removed after 12 hours.
+1. In the **Clone details** page of the Postgres.ai web interface, copy and run
+   the command to start SSH port forwarding for the clone.
+1. In the **Clone details** page of the Postgres.ai web interface, copy and run the `psql` connection string.
+   Use the password provided at setup.
+
+After you connect, use clone like you would any `psql` console in production, but with
+the added benefit and safety of an isolated writeable environment.
diff --git a/doc/development/event_store.md b/doc/development/event_store.md
index b00a824e2eb..2f6acc5f6dc 100644
--- a/doc/development/event_store.md
+++ b/doc/development/event_store.md
@@ -290,3 +290,43 @@ executed synchronously every time the given event is published.
 
 For complex conditions it's best to subscribe to all the events and then handle the logic
 in the `handle_event` method of the subscriber worker.
+
+## Testing
+
+A publisher doesn't must care what subscribed to the event being published. The publisher's
+responsibility is to ensure that the event is published correctly.
+
+To test that an event has been published correctly, we can use the RSpec matcher `:publish_event`:
+
+```ruby
+it 'publishes a ProjectDeleted event with project id and namespace id' do
+  expected_data = { project_id: project.id, namespace_id: project.namespace_id }
+
+  # The matcher verifies that when the block is called, the block publishes the expected event and data.
+  expect { destroy_project(project, user, {}) }
+    .to publish_event(Projects::ProjectDeletedEvent)
+    .with(expected_data)
+end
+```
+
+The subscriber must ensure that a published event can be consumed correctly. For this purpose
+we have added helpers and shared examples to standardize the way we test subscribers:
+
+```ruby
+RSpec.describe MergeRequests::UpdateHeadPipelineWorker do
+  let(:event) { Ci::PipelineCreatedEvent.new(data: ({ pipeline_id: pipeline.id })) }
+
+  # This shared example ensures that an event is published and correctly processed by
+  # the current subscriber (`described_class`).
+  it_behaves_like 'consumes the published event' do
+    let(:event) { event }
+  end
+  
+  it 'does something' do
+    # This helper directly executes `perform` ensuring that `handle_event` is called correctly.
+    consume_event(subscriber: described_class, event: event)
+
+    # run expectations
+  end
+end
+```
diff --git a/doc/user/discussions/index.md b/doc/user/discussions/index.md
index a6343e0d1cf..48e392fe140 100644
--- a/doc/user/discussions/index.md
+++ b/doc/user/discussions/index.md
@@ -112,12 +112,27 @@ you can reply to comments by sending an email.
 
 You can use [Markdown](../markdown.md) and [quick actions](../project/quick_actions.md) in your email replies.
 
-## Who can edit comments
+## Edit a comment
 
 You can edit your own comment at any time.
-
 Anyone with at least the Maintainer role can also edit a comment made by someone else.
 
+To edit a comment:
+
+1. On the comment, select **Edit comment** (**{pencil}**).
+1. Make your edits.
+1. Select **Save changes**.
+
+### Editing a comment to add a mention
+
+By default, when you mention a user, GitLab [creates a to-do item](../todos.md#actions-that-create-to-do-items)
+for them, and sends them a [notification email](../profile/notifications.md).
+
+If you edit an existing comment to add a user mention that wasn't there before, GitLab:
+
+- Creates a to-do item for the mentioned user.
+- Does not send a notification email.
+
 ## Prevent comments by locking an issue
 
 You can prevent public comments in an issue or merge request.
diff --git a/doc/user/profile/notifications.md b/doc/user/profile/notifications.md
index 4bc1c22fc63..ca85fd7be05 100644
--- a/doc/user/profile/notifications.md
+++ b/doc/user/profile/notifications.md
@@ -21,11 +21,14 @@ that happen there.
 You might receive notifications for one of the following reasons:
 
 - You participate in an issue, merge request, epic, or design. You become a participant when you comment
-  or edit, or someone mentions you.
+  or edit, or someone mentions <sup>1</sup> you.
 - You've [enabled notifications in an issue, merge request, or epic](#notifications-on-issues-merge-requests-and-epics).
 - You've configured notifications for the [project](#change-level-of-project-notifications) or [group](#group-notifications).
 - You're subscribed to group or project pipeline notifications via the pipeline emails [integration](../project/integrations/overview.md).
 
+1. GitLab doesn't send a notification when
+   [a comment is edited to include a user mention](../discussions/index.md#editing-a-comment-to-add-a-mention).
+
 NOTE:
 Administrators can block notifications, preventing them from being sent.
 
diff --git a/lib/backup/manager.rb b/lib/backup/manager.rb
index cb5fd959bc9..a7480258899 100644
--- a/lib/backup/manager.rb
+++ b/lib/backup/manager.rb
@@ -88,34 +88,33 @@ module Backup
         remove_old
       end
 
-      progress.puts "Warning: Your gitlab.rb and gitlab-secrets.json files contain sensitive data \n" \
+      puts_time "Warning: Your gitlab.rb and gitlab-secrets.json files contain sensitive data \n" \
            "and are not included in this backup. You will need these files to restore a backup.\n" \
            "Please back them up manually.".color(:red)
-      progress.puts "Backup task is done."
+      puts_time "Backup task is done."
     end
 
     def run_create_task(task_name)
       definition = @definitions[task_name]
 
       build_backup_information
-      puts_time "Dumping #{definition.task.human_name} ... ".color(:blue)
 
       unless definition.task.enabled
-        puts_time "[DISABLED]".color(:cyan)
+        puts_time "Dumping #{definition.task.human_name} ... ".color(:blue) + "[DISABLED]".color(:cyan)
         return
       end
 
       if skipped?(task_name)
-        puts_time "[SKIPPED]".color(:cyan)
+        puts_time "Dumping #{definition.task.human_name} ... ".color(:blue) + "[SKIPPED]".color(:cyan)
         return
       end
 
+      puts_time "Dumping #{definition.task.human_name} ... ".color(:blue)
       definition.task.dump(File.join(Gitlab.config.backup.path, definition.destination_path))
-
-      puts_time "done".color(:green)
+      puts_time "Dumping #{definition.task.human_name} ... ".color(:blue) + "done".color(:green)
 
     rescue Backup::DatabaseBackupError, Backup::FileBackupError => e
-      progress.puts "#{e.message}"
+      puts_time "Dumping #{definition.task.human_name} failed: #{e.message}".color(:red)
     end
 
     def restore
@@ -136,21 +135,21 @@ module Backup
 
       remove_tmp
 
-      puts "Warning: Your gitlab.rb and gitlab-secrets.json files contain sensitive data \n" \
-           "and are not included in this backup. You will need to restore these files manually.".color(:red)
-      puts "Restore task is done."
+      puts_time "Warning: Your gitlab.rb and gitlab-secrets.json files contain sensitive data \n" \
+        "and are not included in this backup. You will need to restore these files manually.".color(:red)
+      puts_time "Restore task is done."
     end
 
     def run_restore_task(task_name)
       definition = @definitions[task_name]
 
-      puts_time "Restoring #{definition.task.human_name} ... ".color(:blue)
-
       unless definition.task.enabled
-        puts_time "[DISABLED]".color(:cyan)
+        puts_time "Restoring #{definition.task.human_name} ... ".color(:blue) + "[DISABLED]".color(:cyan)
         return
       end
 
+      puts_time "Restoring #{definition.task.human_name} ... ".color(:blue)
+
       warning = definition.task.pre_restore_warning
       if warning.present?
         puts_time warning.color(:red)
@@ -159,7 +158,7 @@ module Backup
 
       definition.task.restore(File.join(Gitlab.config.backup.path, definition.destination_path))
 
-      puts_time "done".color(:green)
+      puts_time "Restoring #{definition.task.human_name} ... ".color(:blue) + "done".color(:green)
 
       warning = definition.task.post_restore_warning
       if warning.present?
@@ -209,103 +208,104 @@ module Backup
     def pack
       Dir.chdir(backup_path) do
         # create archive
-        progress.print "Creating backup archive: #{tar_file} ... "
+        puts_time "Creating backup archive: #{tar_file} ... ".color(:blue)
         # Set file permissions on open to prevent chmod races.
         tar_system_options = { out: [tar_file, 'w', Gitlab.config.backup.archive_permissions] }
         if Kernel.system('tar', '-cf', '-', *backup_contents, tar_system_options)
-          progress.puts "done".color(:green)
+          puts_time "Creating backup archive: #{tar_file} ... ".color(:blue) + 'done'.color(:green)
         else
-          puts "creating archive #{tar_file} failed".color(:red)
+          puts_time "Creating archive #{tar_file} failed".color(:red)
           raise Backup::Error, 'Backup failed'
         end
       end
     end
 
     def upload
-      progress.print "Uploading backup archive to remote storage #{remote_directory} ... "
-
       connection_settings = Gitlab.config.backup.upload.connection
       if connection_settings.blank?
-        progress.puts "skipped".color(:yellow)
+        puts_time "Uploading backup archive to remote storage #{remote_directory} ... ".color(:blue) + "[SKIPPED]".color(:cyan)
         return
       end
 
+      puts_time "Uploading backup archive to remote storage #{remote_directory} ... ".color(:blue)
+
       directory = connect_to_remote_directory
       upload = directory.files.create(create_attributes)
 
       if upload
         if upload.respond_to?(:encryption) && upload.encryption
-          progress.puts "done (encrypted with #{upload.encryption})".color(:green)
+          puts_time "Uploading backup archive to remote storage #{remote_directory} ... ".color(:blue) + "done (encrypted with #{upload.encryption})".color(:green)
         else
-          progress.puts "done".color(:green)
+          puts_time "Uploading backup archive to remote storage #{remote_directory} ... ".color(:blue) + "done".color(:green)
         end
       else
-        puts "uploading backup to #{remote_directory} failed".color(:red)
+        puts_time "Uploading backup to #{remote_directory} failed".color(:red)
         raise Backup::Error, 'Backup failed'
       end
     end
 
     def cleanup
-      progress.print "Deleting tmp directories ... "
+      puts_time "Deleting tar staging files ... ".color(:blue)
 
       remove_backup_path(MANIFEST_NAME)
       @definitions.each do |_, definition|
         remove_backup_path(definition.cleanup_path || definition.destination_path)
       end
+
+      puts_time "Deleting tar staging files ... ".color(:blue) + 'done'.color(:green)
     end
 
     def remove_backup_path(path)
-      return unless File.exist?(File.join(backup_path, path))
+      absolute_path = File.join(backup_path, path)
+      return unless File.exist?(absolute_path)
 
-      FileUtils.rm_rf(File.join(backup_path, path))
-      progress.puts "done".color(:green)
+      puts_time "Cleaning up #{absolute_path}"
+      FileUtils.rm_rf(absolute_path)
     end
 
     def remove_tmp
       # delete tmp inside backups
-      progress.print "Deleting backups/tmp ... "
+      puts_time "Deleting backups/tmp ... ".color(:blue)
 
-      if FileUtils.rm_rf(File.join(backup_path, "tmp"))
-        progress.puts "done".color(:green)
-      else
-        puts "deleting backups/tmp failed".color(:red)
-      end
+      FileUtils.rm_rf(File.join(backup_path, "tmp"))
+      puts_time "Deleting backups/tmp ... ".color(:blue) + "done".color(:green)
     end
 
     def remove_old
       # delete backups
-      progress.print "Deleting old backups ... "
       keep_time = Gitlab.config.backup.keep_time.to_i
 
-      if keep_time > 0
-        removed = 0
+      if keep_time <= 0
+        puts_time "Deleting old backups ... ".color(:blue) + "[SKIPPED]".color(:cyan)
+        return
+      end
 
-        Dir.chdir(backup_path) do
-          backup_file_list.each do |file|
-            # For backward compatibility, there are 3 names the backups can have:
-            # - 1495527122_gitlab_backup.tar
-            # - 1495527068_2017_05_23_gitlab_backup.tar
-            # - 1495527097_2017_05_23_9.3.0-pre_gitlab_backup.tar
-            matched = backup_file?(file)
-            next unless matched
+      puts_time "Deleting old backups ... ".color(:blue)
+      removed = 0
 
-            timestamp = matched[1].to_i
+      Dir.chdir(backup_path) do
+        backup_file_list.each do |file|
+          # For backward compatibility, there are 3 names the backups can have:
+          # - 1495527122_gitlab_backup.tar
+          # - 1495527068_2017_05_23_gitlab_backup.tar
+          # - 1495527097_2017_05_23_9.3.0-pre_gitlab_backup.tar
+          matched = backup_file?(file)
+          next unless matched
 
-            if Time.at(timestamp) < (Time.now - keep_time)
-              begin
-                FileUtils.rm(file)
-                removed += 1
-              rescue StandardError => e
-                progress.puts "Deleting #{file} failed: #{e.message}".color(:red)
-              end
+          timestamp = matched[1].to_i
+
+          if Time.at(timestamp) < (Time.now - keep_time)
+            begin
+              FileUtils.rm(file)
+              removed += 1
+            rescue StandardError => e
+              puts_time "Deleting #{file} failed: #{e.message}".color(:red)
             end
           end
         end
-
-        progress.puts "done. (#{removed} removed)".color(:green)
-      else
-        progress.puts "skipping".color(:yellow)
       end
+
+      puts_time "Deleting old backups ... ".color(:blue) + "done. (#{removed} removed)".color(:green)
     end
 
     def verify_backup_version
@@ -327,7 +327,7 @@ module Backup
 
     def unpack
       if ENV['BACKUP'].blank? && non_tarred_backup?
-        progress.puts "Non tarred backup found in #{backup_path}, using that"
+        puts_time "Non tarred backup found in #{backup_path}, using that"
 
         return false
       end
@@ -335,15 +335,15 @@ module Backup
       Dir.chdir(backup_path) do
         # check for existing backups in the backup dir
         if backup_file_list.empty?
-          progress.puts "No backups found in #{backup_path}"
-          progress.puts "Please make sure that file name ends with #{FILE_NAME_SUFFIX}"
+          puts_time "No backups found in #{backup_path}"
+          puts_time "Please make sure that file name ends with #{FILE_NAME_SUFFIX}"
           exit 1
         elsif backup_file_list.many? && ENV["BACKUP"].nil?
-          progress.puts 'Found more than one backup:'
+          puts_time 'Found more than one backup:'
           # print list of available backups
-          progress.puts " " + available_timestamps.join("\n ")
-          progress.puts 'Please specify which one you want to restore:'
-          progress.puts 'rake gitlab:backup:restore BACKUP=timestamp_of_backup'
+          puts_time " " + available_timestamps.join("\n ")
+          puts_time 'Please specify which one you want to restore:'
+          puts_time 'rake gitlab:backup:restore BACKUP=timestamp_of_backup'
           exit 1
         end
 
@@ -354,16 +354,16 @@ module Backup
                    end
 
         unless File.exist?(tar_file)
-          progress.puts "The backup file #{tar_file} does not exist!"
+          puts_time "The backup file #{tar_file} does not exist!"
           exit 1
         end
 
-        progress.print 'Unpacking backup ... '
+        puts_time 'Unpacking backup ... '.color(:blue)
 
         if Kernel.system(*%W(tar -xf #{tar_file}))
-          progress.puts 'done'.color(:green)
+          puts_time 'Unpacking backup ... '.color(:blue) + 'done'.color(:green)
         else
-          progress.puts 'unpacking backup failed'.color(:red)
+          puts_time 'Unpacking backup failed'.color(:red)
           exit 1
         end
       end
diff --git a/spec/features/groups/members/manage_groups_spec.rb b/spec/features/groups/members/manage_groups_spec.rb
index 5ab5a7ea716..316ad5e3f81 100644
--- a/spec/features/groups/members/manage_groups_spec.rb
+++ b/spec/features/groups/members/manage_groups_spec.rb
@@ -3,7 +3,6 @@
 require 'spec_helper'
 
 RSpec.describe 'Groups > Members > Manage groups', :js do
-  include Select2Helper
   include Spec::Support::Helpers::Features::MembersHelpers
   include Spec::Support::Helpers::Features::InviteMembersModalHelper
   include Spec::Support::Helpers::ModalHelpers
@@ -119,16 +118,92 @@ RSpec.describe 'Groups > Members > Manage groups', :js do
 
   describe 'group search results' do
     let_it_be(:group, refind: true) { create(:group) }
-    let_it_be(:group_within_hierarchy) { create(:group, parent: group) }
-    let_it_be(:group_outside_hierarchy) { create(:group) }
 
-    before_all do
-      group.add_owner(user)
-      group_within_hierarchy.add_owner(user)
-      group_outside_hierarchy.add_owner(user)
+    context 'with instance admin considerations' do
+      let_it_be(:group_to_share) { create(:group) }
+
+      context 'when user is an admin' do
+        let_it_be(:admin) { create(:admin) }
+
+        before do
+          sign_in(admin)
+          gitlab_enable_admin_mode_sign_in(admin)
+        end
+
+        it 'shows groups where the admin has no direct membership' do
+          visit group_group_members_path(group)
+
+          click_on 'Invite a group'
+          click_on 'Select a group'
+          wait_for_requests
+
+          page.within(group_dropdown_selector) do
+            expect_to_have_group(group_to_share)
+            expect_not_to_have_group(group)
+          end
+        end
+
+        it 'shows groups where the admin has at least guest level membership' do
+          group_to_share.add_guest(admin)
+
+          visit group_group_members_path(group)
+
+          click_on 'Invite a group'
+          click_on 'Select a group'
+          wait_for_requests
+
+          page.within(group_dropdown_selector) do
+            expect_to_have_group(group_to_share)
+            expect_not_to_have_group(group)
+          end
+        end
+      end
+
+      context 'when user is not an admin' do
+        before do
+          group.add_owner(user)
+        end
+
+        it 'shows groups where the user has no direct membership' do
+          visit group_group_members_path(group)
+
+          click_on 'Invite a group'
+          click_on 'Select a group'
+          wait_for_requests
+
+          page.within(group_dropdown_selector) do
+            expect_not_to_have_group(group_to_share)
+            expect_not_to_have_group(group)
+          end
+        end
+
+        it 'shows groups where the user has at least guest level membership' do
+          group_to_share.add_guest(user)
+
+          visit group_group_members_path(group)
+
+          click_on 'Invite a group'
+          click_on 'Select a group'
+          wait_for_requests
+
+          page.within(group_dropdown_selector) do
+            expect_to_have_group(group_to_share)
+            expect_not_to_have_group(group)
+          end
+        end
+      end
     end
 
-    context 'when the invite members group modal is enabled' do
+    context 'when user is not an admin and there are hierarchy considerations' do
+      let_it_be(:group_within_hierarchy) { create(:group, parent: group) }
+      let_it_be(:group_outside_hierarchy) { create(:group) }
+
+      before_all do
+        group.add_owner(user)
+        group_within_hierarchy.add_owner(user)
+        group_outside_hierarchy.add_owner(user)
+      end
+
       it 'does not show self or ancestors', :aggregate_failures do
         group_sibbling = create(:group, parent: group)
         group_sibbling.add_owner(user)
@@ -139,40 +214,45 @@ RSpec.describe 'Groups > Members > Manage groups', :js do
         click_on 'Select a group'
         wait_for_requests
 
-        page.within('[data-testid="group-select-dropdown"]') do
-          expect(page).to have_selector("[entity-id='#{group_outside_hierarchy.id}']")
-          expect(page).to have_selector("[entity-id='#{group_sibbling.id}']")
-          expect(page).not_to have_selector("[entity-id='#{group.id}']")
-          expect(page).not_to have_selector("[entity-id='#{group_within_hierarchy.id}']")
+        page.within(group_dropdown_selector) do
+          expect_to_have_group(group_outside_hierarchy)
+          expect_to_have_group(group_sibbling)
+          expect_not_to_have_group(group)
+          expect_not_to_have_group(group_within_hierarchy)
         end
       end
-    end
 
-    context 'when sharing with groups outside the hierarchy is enabled' do
-      it 'shows groups within and outside the hierarchy in search results' do
-        visit group_group_members_path(group)
+      context 'when sharing with groups outside the hierarchy is enabled' do
+        it 'shows groups within and outside the hierarchy in search results' do
+          visit group_group_members_path(group)
 
-        click_on 'Invite a group'
-        click_on 'Select a group'
+          click_on 'Invite a group'
+          click_on 'Select a group'
+          wait_for_requests
 
-        expect(page).to have_text group_within_hierarchy.name
-        expect(page).to have_text group_outside_hierarchy.name
-      end
-    end
-
-    context 'when sharing with groups outside the hierarchy is disabled' do
-      before do
-        group.namespace_settings.update!(prevent_sharing_groups_outside_hierarchy: true)
+          page.within(group_dropdown_selector) do
+            expect_to_have_group(group_within_hierarchy)
+            expect_to_have_group(group_outside_hierarchy)
+          end
+        end
       end
 
-      it 'shows only groups within the hierarchy in search results' do
-        visit group_group_members_path(group)
+      context 'when sharing with groups outside the hierarchy is disabled' do
+        before do
+          group.namespace_settings.update!(prevent_sharing_groups_outside_hierarchy: true)
+        end
 
-        click_on 'Invite a group'
-        click_on 'Select a group'
+        it 'shows only groups within the hierarchy in search results' do
+          visit group_group_members_path(group)
 
-        expect(page).to have_text group_within_hierarchy.name
-        expect(page).not_to have_text group_outside_hierarchy.name
+          click_on 'Invite a group'
+          click_on 'Select a group'
+
+          page.within(group_dropdown_selector) do
+            expect_to_have_group(group_within_hierarchy)
+            expect_not_to_have_group(group_outside_hierarchy)
+          end
+        end
       end
     end
   end
diff --git a/spec/features/projects/blobs/blob_line_permalink_updater_spec.rb b/spec/features/projects/blobs/blob_line_permalink_updater_spec.rb
index 11e2d24c36a..9b0edcd09d2 100644
--- a/spec/features/projects/blobs/blob_line_permalink_updater_spec.rb
+++ b/spec/features/projects/blobs/blob_line_permalink_updater_spec.rb
@@ -39,7 +39,7 @@ RSpec.describe 'Blob button line permalinks (BlobLinePermalinkUpdater)', :js do
         find('#L3').click
         find("#L5").click
 
-        expect(find('.js-data-file-blob-permalink-url')['href']).to eq(get_absolute_url(project_blob_path(project, tree_join(sha, path), anchor: "LC5")))
+        expect(find('.js-data-file-blob-permalink-url')['href']).to eq(get_absolute_url(project_blob_path(project, tree_join(sha, path), anchor: "L5")))
       end
 
       it 'with initial fragment hash, changes fragment hash if line number clicked' do
@@ -50,7 +50,7 @@ RSpec.describe 'Blob button line permalinks (BlobLinePermalinkUpdater)', :js do
         find('#L3').click
         find("#L5").click
 
-        expect(find('.js-data-file-blob-permalink-url')['href']).to eq(get_absolute_url(project_blob_path(project, tree_join(sha, path), anchor: "LC5")))
+        expect(find('.js-data-file-blob-permalink-url')['href']).to eq(get_absolute_url(project_blob_path(project, tree_join(sha, path), anchor: "L5")))
       end
     end
 
@@ -75,7 +75,7 @@ RSpec.describe 'Blob button line permalinks (BlobLinePermalinkUpdater)', :js do
         find('#L3').click
         find("#L5").click
 
-        expect(find('.js-blob-blame-link')['href']).to eq(get_absolute_url(project_blame_path(project, tree_join('master', path), anchor: "LC5")))
+        expect(find('.js-blob-blame-link')['href']).to eq(get_absolute_url(project_blame_path(project, tree_join('master', path), anchor: "L5")))
       end
 
       it 'with initial fragment hash, changes fragment hash if line number clicked' do
@@ -86,7 +86,7 @@ RSpec.describe 'Blob button line permalinks (BlobLinePermalinkUpdater)', :js do
         find('#L3').click
         find("#L5").click
 
-        expect(find('.js-blob-blame-link')['href']).to eq(get_absolute_url(project_blame_path(project, tree_join('master', path), anchor: "LC5")))
+        expect(find('.js-blob-blame-link')['href']).to eq(get_absolute_url(project_blame_path(project, tree_join('master', path), anchor: "L5")))
       end
     end
   end
diff --git a/spec/features/projects/members/invite_group_spec.rb b/spec/features/projects/members/invite_group_spec.rb
index 9c256504934..a48229249e0 100644
--- a/spec/features/projects/members/invite_group_spec.rb
+++ b/spec/features/projects/members/invite_group_spec.rb
@@ -17,20 +17,18 @@ RSpec.describe 'Project > Members > Invite group', :js do
 
     visit project_project_members_path(project)
 
-    expect(page).to have_selector('button[data-test-id="invite-group-button"]')
+    expect(page).to have_selector(invite_group_selector)
   end
 
-  it 'does not display  the  button when visiting the page not signed in' do
+  it 'does not display the button when visiting the page not signed in' do
     project = create(:project, namespace: create(:group))
 
     visit project_project_members_path(project)
 
-    expect(page).not_to have_selector('button[data-test-id="invite-group-button"]')
+    expect(page).not_to have_selector(invite_group_selector)
   end
 
   describe 'Share with group lock' do
-    let(:invite_group_selector) { 'button[data-test-id="invite-group-button"]' }
-
     shared_examples 'the project can be shared with groups' do
       it 'the "Invite a group" button exists' do
         visit project_project_members_path(project)
@@ -158,21 +156,95 @@ RSpec.describe 'Project > Members > Invite group', :js do
   describe 'the groups dropdown' do
     let_it_be(:parent_group) { create(:group, :public) }
     let_it_be(:project_group) { create(:group, :public, parent: parent_group) }
-    let_it_be(:public_sub_subgroup) { create(:group, :public, parent: project_group) }
-    let_it_be(:public_sibbling_group) { create(:group, :public, parent: parent_group) }
-    let_it_be(:private_sibbling_group) { create(:group, :private, parent: parent_group) }
-    let_it_be(:private_membership_group) { create(:group, :private) }
-    let_it_be(:public_membership_group) { create(:group, :public) }
     let_it_be(:project) { create(:project, group: project_group) }
 
-    before do
-      private_membership_group.add_guest(maintainer)
-      public_membership_group.add_maintainer(maintainer)
+    context 'with instance admin considerations' do
+      let_it_be(:group_to_share) { create(:group) }
 
-      sign_in(maintainer)
+      context 'when user is an admin' do
+        let_it_be(:admin) { create(:admin) }
+
+        before do
+          sign_in(admin)
+          gitlab_enable_admin_mode_sign_in(admin)
+        end
+
+        it 'shows groups where the admin has no direct membership' do
+          visit project_project_members_path(project)
+
+          click_on 'Invite a group'
+          click_on 'Select a group'
+          wait_for_requests
+
+          page.within(group_dropdown_selector) do
+            expect_to_have_group(group_to_share)
+          end
+        end
+
+        it 'shows groups where the admin has at least guest level membership' do
+          group_to_share.add_guest(admin)
+
+          visit project_project_members_path(project)
+
+          click_on 'Invite a group'
+          click_on 'Select a group'
+          wait_for_requests
+
+          page.within(group_dropdown_selector) do
+            expect_to_have_group(group_to_share)
+          end
+        end
+      end
+
+      context 'when user is not an admin' do
+        before do
+          project.add_maintainer(maintainer)
+          sign_in(maintainer)
+        end
+
+        it 'does not show groups where the user has no direct membership' do
+          visit project_project_members_path(project)
+
+          click_on 'Invite a group'
+          click_on 'Select a group'
+          wait_for_requests
+
+          page.within(group_dropdown_selector) do
+            expect_not_to_have_group(group_to_share)
+          end
+        end
+
+        it 'shows groups where the user has at least guest level membership' do
+          group_to_share.add_guest(maintainer)
+
+          visit project_project_members_path(project)
+
+          click_on 'Invite a group'
+          click_on 'Select a group'
+          wait_for_requests
+
+          page.within(group_dropdown_selector) do
+            expect_to_have_group(group_to_share)
+          end
+        end
+      end
     end
 
     context 'for a project in a nested group' do
+      let_it_be(:public_sub_subgroup) { create(:group, :public, parent: project_group) }
+      let_it_be(:public_sibbling_group) { create(:group, :public, parent: parent_group) }
+      let_it_be(:private_sibbling_group) { create(:group, :private, parent: parent_group) }
+      let_it_be(:private_membership_group) { create(:group, :private) }
+      let_it_be(:public_membership_group) { create(:group, :public) }
+      let_it_be(:project) { create(:project, group: project_group) }
+
+      before do
+        private_membership_group.add_guest(maintainer)
+        public_membership_group.add_maintainer(maintainer)
+
+        sign_in(maintainer)
+      end
+
       it 'does not show the groups inherited from projects' do
         project.add_maintainer(maintainer)
         public_sibbling_group.add_maintainer(maintainer)
@@ -183,7 +255,7 @@ RSpec.describe 'Project > Members > Invite group', :js do
         click_on 'Select a group'
         wait_for_requests
 
-        page.within('[data-testid="group-select-dropdown"]') do
+        page.within(group_dropdown_selector) do
           expect_to_have_group(public_membership_group)
           expect_to_have_group(public_sibbling_group)
           expect_to_have_group(private_membership_group)
@@ -204,7 +276,7 @@ RSpec.describe 'Project > Members > Invite group', :js do
         click_on 'Select a group'
         wait_for_requests
 
-        page.within('[data-testid="group-select-dropdown"]') do
+        page.within(group_dropdown_selector) do
           expect_to_have_group(public_membership_group)
           expect_to_have_group(public_sibbling_group)
           expect_to_have_group(private_membership_group)
@@ -215,14 +287,10 @@ RSpec.describe 'Project > Members > Invite group', :js do
           expect_not_to_have_group(project_group)
         end
       end
-
-      def expect_to_have_group(group)
-        expect(page).to have_selector("[entity-id='#{group.id}']")
-      end
-
-      def expect_not_to_have_group(group)
-        expect(page).not_to have_selector("[entity-id='#{group.id}']")
-      end
     end
   end
+
+  def invite_group_selector
+    'button[data-test-id="invite-group-button"]'
+  end
 end
diff --git a/spec/frontend/invite_members/components/group_select_spec.js b/spec/frontend/invite_members/components/group_select_spec.js
index 192f3fdd381..e1563a7bb3a 100644
--- a/spec/frontend/invite_members/components/group_select_spec.js
+++ b/spec/frontend/invite_members/components/group_select_spec.js
@@ -4,7 +4,6 @@ import waitForPromises from 'helpers/wait_for_promises';
 import * as groupsApi from '~/api/groups_api';
 import GroupSelect from '~/invite_members/components/group_select.vue';
 
-const accessLevels = { Guest: 10, Reporter: 20, Developer: 30, Maintainer: 40, Owner: 50 };
 const group1 = { id: 1, full_name: 'Group One', avatar_url: 'test' };
 const group2 = { id: 2, full_name: 'Group Two', avatar_url: 'test' };
 const allGroups = [group1, group2];
@@ -13,7 +12,6 @@ const createComponent = (props = {}) => {
   return mount(GroupSelect, {
     propsData: {
       invalidGroups: [],
-      accessLevels,
       ...props,
     },
   });
@@ -66,9 +64,8 @@ describe('GroupSelect', () => {
       resolveApiRequest({ data: allGroups });
 
       expect(groupsApi.getGroups).toHaveBeenCalledWith(group1.name, {
-        active: true,
         exclude_internal: true,
-        min_access_level: accessLevels.Guest,
+        active: true,
       });
     });
 
diff --git a/spec/frontend/vue_shared/components/line_numbers_spec.js b/spec/frontend/vue_shared/components/line_numbers_spec.js
deleted file mode 100644
index 38c26226863..00000000000
--- a/spec/frontend/vue_shared/components/line_numbers_spec.js
+++ /dev/null
@@ -1,37 +0,0 @@
-import { shallowMount } from '@vue/test-utils';
-import { GlIcon, GlLink } from '@gitlab/ui';
-import LineNumbers from '~/vue_shared/components/line_numbers.vue';
-
-describe('Line Numbers component', () => {
-  let wrapper;
-  const lines = 10;
-
-  const createComponent = () => {
-    wrapper = shallowMount(LineNumbers, { propsData: { lines } });
-  };
-
-  const findGlIcon = () => wrapper.findComponent(GlIcon);
-  const findLineNumbers = () => wrapper.findAllComponents(GlLink);
-  const findFirstLineNumber = () => findLineNumbers().at(0);
-
-  beforeEach(() => createComponent());
-
-  afterEach(() => wrapper.destroy());
-
-  describe('rendering', () => {
-    it('renders Line Numbers', () => {
-      expect(findLineNumbers().length).toBe(lines);
-      expect(findFirstLineNumber().attributes()).toMatchObject({
-        id: 'L1',
-        to: '#LC1',
-      });
-    });
-
-    it('renders a link icon', () => {
-      expect(findGlIcon().props()).toMatchObject({
-        size: 12,
-        name: 'link',
-      });
-    });
-  });
-});
diff --git a/spec/frontend/vue_shared/components/source_viewer/components/chunk_line_spec.js b/spec/frontend/vue_shared/components/source_viewer/components/chunk_line_spec.js
new file mode 100644
index 00000000000..4aa0aea9605
--- /dev/null
+++ b/spec/frontend/vue_shared/components/source_viewer/components/chunk_line_spec.js
@@ -0,0 +1,47 @@
+import { GlLink } from '@gitlab/ui';
+import { shallowMountExtended } from 'helpers/vue_test_utils_helper';
+import ChunkLine from '~/vue_shared/components/source_viewer/components/chunk_line.vue';
+
+const DEFAULT_PROPS = {
+  number: 2,
+  content: '// Line content',
+  language: 'javascript',
+};
+
+describe('Chunk Line component', () => {
+  let wrapper;
+
+  const createComponent = (props = {}) => {
+    wrapper = shallowMountExtended(ChunkLine, { propsData: { ...DEFAULT_PROPS, ...props } });
+  };
+
+  const findLink = () => wrapper.findComponent(GlLink);
+  const findContent = () => wrapper.findByTestId('content');
+
+  beforeEach(() => {
+    createComponent();
+  });
+
+  afterEach(() => wrapper.destroy());
+
+  describe('rendering', () => {
+    it('renders a line number', () => {
+      expect(findLink().attributes()).toMatchObject({
+        'data-line-number': `${DEFAULT_PROPS.number}`,
+        to: `#L${DEFAULT_PROPS.number}`,
+        id: `L${DEFAULT_PROPS.number}`,
+      });
+
+      expect(findLink().text()).toBe(DEFAULT_PROPS.number.toString());
+    });
+
+    it('renders content', () => {
+      expect(findContent().attributes()).toMatchObject({
+        id: `LC${DEFAULT_PROPS.number}`,
+        lang: DEFAULT_PROPS.language,
+      });
+
+      expect(findContent().text()).toBe(DEFAULT_PROPS.content);
+    });
+  });
+});
diff --git a/spec/frontend/vue_shared/components/source_viewer/components/chunk_spec.js b/spec/frontend/vue_shared/components/source_viewer/components/chunk_spec.js
new file mode 100644
index 00000000000..42c4f2eacb8
--- /dev/null
+++ b/spec/frontend/vue_shared/components/source_viewer/components/chunk_spec.js
@@ -0,0 +1,82 @@
+import { GlIntersectionObserver } from '@gitlab/ui';
+import { shallowMountExtended } from 'helpers/vue_test_utils_helper';
+import Chunk from '~/vue_shared/components/source_viewer/components/chunk.vue';
+import ChunkLine from '~/vue_shared/components/source_viewer/components/chunk_line.vue';
+
+const DEFAULT_PROPS = {
+  chunkIndex: 2,
+  isHighlighted: false,
+  content: '// Line 1 content \n // Line 2 content',
+  startingFrom: 140,
+  totalLines: 50,
+  language: 'javascript',
+};
+
+describe('Chunk component', () => {
+  let wrapper;
+
+  const createComponent = (props = {}) => {
+    wrapper = shallowMountExtended(Chunk, { propsData: { ...DEFAULT_PROPS, ...props } });
+  };
+
+  const findIntersectionObserver = () => wrapper.findComponent(GlIntersectionObserver);
+  const findChunkLines = () => wrapper.findAllComponents(ChunkLine);
+  const findLineNumbers = () => wrapper.findAllByTestId('line-number');
+  const findContent = () => wrapper.findByTestId('content');
+
+  beforeEach(() => {
+    createComponent();
+  });
+
+  afterEach(() => wrapper.destroy());
+
+  describe('Intersection observer', () => {
+    it('renders an Intersection observer component', () => {
+      expect(findIntersectionObserver().exists()).toBe(true);
+    });
+
+    it('emits an appear event when intersection-observer appears', () => {
+      findIntersectionObserver().vm.$emit('appear');
+
+      expect(wrapper.emitted('appear')).toEqual([[DEFAULT_PROPS.chunkIndex]]);
+    });
+
+    it('does not emit an appear event is isHighlighted is true', () => {
+      createComponent({ isHighlighted: true });
+      findIntersectionObserver().vm.$emit('appear');
+
+      expect(wrapper.emitted('appear')).toEqual(undefined);
+    });
+  });
+
+  describe('rendering', () => {
+    it('does not render a Chunk Line component if isHighlighted is false', () => {
+      expect(findChunkLines().length).toBe(0);
+    });
+
+    it('renders simplified line numbers and content if isHighlighted is false', () => {
+      expect(findLineNumbers().length).toBe(DEFAULT_PROPS.totalLines);
+
+      expect(findLineNumbers().at(0).attributes()).toMatchObject({
+        'data-line-number': `${DEFAULT_PROPS.startingFrom + 1}`,
+        href: `#L${DEFAULT_PROPS.startingFrom + 1}`,
+        id: `L${DEFAULT_PROPS.startingFrom + 1}`,
+      });
+
+      expect(findContent().text()).toBe(DEFAULT_PROPS.content);
+    });
+
+    it('renders Chunk Line components if isHighlighted is true', () => {
+      const splitContent = DEFAULT_PROPS.content.split('\n');
+      createComponent({ isHighlighted: true });
+
+      expect(findChunkLines().length).toBe(splitContent.length);
+
+      expect(findChunkLines().at(0).props()).toMatchObject({
+        number: DEFAULT_PROPS.startingFrom + 1,
+        content: splitContent[0],
+        language: DEFAULT_PROPS.language,
+      });
+    });
+  });
+});
diff --git a/spec/frontend/vue_shared/components/source_viewer/source_viewer_spec.js b/spec/frontend/vue_shared/components/source_viewer/source_viewer_spec.js
index ab579945e22..5b787993492 100644
--- a/spec/frontend/vue_shared/components/source_viewer/source_viewer_spec.js
+++ b/spec/frontend/vue_shared/components/source_viewer/source_viewer_spec.js
@@ -1,23 +1,35 @@
 import hljs from 'highlight.js/lib/core';
-import { GlLoadingIcon } from '@gitlab/ui';
-import Vue, { nextTick } from 'vue';
+import Vue from 'vue';
 import VueRouter from 'vue-router';
 import { shallowMountExtended } from 'helpers/vue_test_utils_helper';
 import SourceViewer from '~/vue_shared/components/source_viewer/source_viewer.vue';
+import Chunk from '~/vue_shared/components/source_viewer/components/chunk.vue';
 import { ROUGE_TO_HLJS_LANGUAGE_MAP } from '~/vue_shared/components/source_viewer/constants';
-import LineNumbers from '~/vue_shared/components/line_numbers.vue';
 import waitForPromises from 'helpers/wait_for_promises';
-import * as sourceViewerUtils from '~/vue_shared/components/source_viewer/utils';
+import LineHighlighter from '~/blob/line_highlighter';
 
+jest.mock('~/blob/line_highlighter');
 jest.mock('highlight.js/lib/core');
 Vue.use(VueRouter);
 const router = new VueRouter();
 
+const generateContent = (content, totalLines = 1) => {
+  let generatedContent = '';
+  for (let i = 0; i < totalLines; i += 1) {
+    generatedContent += `Line: ${i + 1} = ${content}\n`;
+  }
+  return generatedContent;
+};
+
+const execImmediately = (callback) => callback();
+
 describe('Source Viewer component', () => {
   let wrapper;
   const language = 'docker';
   const mappedLanguage = ROUGE_TO_HLJS_LANGUAGE_MAP[language];
-  const content = `// Some source code`;
+  const chunk1 = generateContent('// Some source code 1', 70);
+  const chunk2 = generateContent('// Some source code 2', 70);
+  const content = chunk1 + chunk2;
   const DEFAULT_BLOB_DATA = { language, rawTextBlob: content };
   const highlightedContent = `<span data-testid='test-highlighted' id='LC1'>${content}</span><span id='LC2'></span>`;
 
@@ -29,15 +41,12 @@ describe('Source Viewer component', () => {
     await waitForPromises();
   };
 
-  const findLoadingIcon = () => wrapper.findComponent(GlLoadingIcon);
-  const findLineNumbers = () => wrapper.findComponent(LineNumbers);
-  const findHighlightedContent = () => wrapper.findByTestId('test-highlighted');
-  const findFirstLine = () => wrapper.find('#LC1');
+  const findChunks = () => wrapper.findAllComponents(Chunk);
 
   beforeEach(() => {
     hljs.highlight.mockImplementation(() => ({ value: highlightedContent }));
     hljs.highlightAuto.mockImplementation(() => ({ value: highlightedContent }));
-    jest.spyOn(sourceViewerUtils, 'wrapLines');
+    jest.spyOn(window, 'requestIdleCallback').mockImplementation(execImmediately);
 
     return createComponent();
   });
@@ -45,6 +54,8 @@ describe('Source Viewer component', () => {
   afterEach(() => wrapper.destroy());
 
   describe('highlight.js', () => {
+    beforeEach(() => createComponent({ language: mappedLanguage }));
+
     it('registers the language definition', async () => {
       const languageDefinition = await import(`highlight.js/lib/languages/${mappedLanguage}`);
 
@@ -54,72 +65,46 @@ describe('Source Viewer component', () => {
       );
     });
 
-    it('highlights the content', () => {
-      expect(hljs.highlight).toHaveBeenCalledWith(content, { language: mappedLanguage });
+    it('highlights the first chunk', () => {
+      expect(hljs.highlight).toHaveBeenCalledWith(chunk1.trim(), { language: mappedLanguage });
     });
 
     describe('auto-detects if a language cannot be loaded', () => {
       beforeEach(() => createComponent({ language: 'some_unknown_language' }));
 
       it('highlights the content with auto-detection', () => {
-        expect(hljs.highlightAuto).toHaveBeenCalledWith(content);
+        expect(hljs.highlightAuto).toHaveBeenCalledWith(chunk1.trim());
       });
     });
   });
 
   describe('rendering', () => {
-    it('renders a loading icon if no highlighted content is available yet', async () => {
-      hljs.highlight.mockImplementation(() => ({ value: null }));
-      await createComponent();
+    it('renders the first chunk', async () => {
+      const firstChunk = findChunks().at(0);
 
-      expect(findLoadingIcon().exists()).toBe(true);
+      expect(firstChunk.props('content')).toContain(chunk1);
+
+      expect(firstChunk.props()).toMatchObject({
+        totalLines: 70,
+        startingFrom: 0,
+      });
     });
 
-    it('calls the wrapLines helper method with highlightedContent and mappedLanguage', () => {
-      expect(sourceViewerUtils.wrapLines).toHaveBeenCalledWith(highlightedContent, mappedLanguage);
-    });
+    it('renders the second chunk', async () => {
+      const secondChunk = findChunks().at(1);
 
-    it('renders Line Numbers', () => {
-      expect(findLineNumbers().props('lines')).toBe(1);
-    });
+      expect(secondChunk.props('content')).toContain(chunk2.trim());
 
-    it('renders the highlighted content', () => {
-      expect(findHighlightedContent().exists()).toBe(true);
-    });
-  });
-
-  describe('selecting a line', () => {
-    let firstLine;
-    let firstLineElement;
-
-    beforeEach(() => {
-      firstLine = findFirstLine();
-      firstLineElement = firstLine.element;
-
-      jest.spyOn(firstLineElement, 'scrollIntoView');
-      jest.spyOn(firstLineElement.classList, 'add');
-      jest.spyOn(firstLineElement.classList, 'remove');
-    });
-
-    it('adds the highlight (hll) class', async () => {
-      wrapper.vm.$router.push('#LC1');
-      await nextTick();
-
-      expect(firstLineElement.classList.add).toHaveBeenCalledWith('hll');
-    });
-
-    it('removes the highlight (hll) class from a previously highlighted line', async () => {
-      wrapper.vm.$router.push('#LC2');
-      await nextTick();
-
-      expect(firstLineElement.classList.remove).toHaveBeenCalledWith('hll');
-    });
-
-    it('scrolls the line into view', () => {
-      expect(firstLineElement.scrollIntoView).toHaveBeenCalledWith({
-        behavior: 'smooth',
-        block: 'center',
+      expect(secondChunk.props()).toMatchObject({
+        totalLines: 70,
+        startingFrom: 70,
       });
     });
   });
+
+  describe('LineHighlighter', () => {
+    it('instantiates the lineHighlighter class', async () => {
+      expect(LineHighlighter).toHaveBeenCalledWith({ scrollBehavior: 'auto' });
+    });
+  });
 });
diff --git a/spec/frontend/vue_shared/components/source_viewer/utils_spec.js b/spec/frontend/vue_shared/components/source_viewer/utils_spec.js
deleted file mode 100644
index 0631e7efd54..00000000000
--- a/spec/frontend/vue_shared/components/source_viewer/utils_spec.js
+++ /dev/null
@@ -1,26 +0,0 @@
-import { wrapLines } from '~/vue_shared/components/source_viewer/utils';
-
-describe('Wrap lines', () => {
-  it.each`
-    content                                            | language             | output
-    ${'line 1'}                                        | ${'javascript'}      | ${'<span id="LC1" lang="javascript" class="line">line 1</span>'}
-    ${'line 1\nline 2'}                                | ${'html'}            | ${`<span id="LC1" lang="html" class="line">line 1</span>\n<span id="LC2" lang="html" class="line">line 2</span>`}
-    ${'<span class="hljs-code">line 1\nline 2</span>'} | ${'html'}            | ${`<span id="LC1" lang="html" class="hljs-code">line 1\n<span id="LC2" lang="html" class="line">line 2</span></span>`}
-    ${'<span class="hljs-code">```bash'}               | ${'bash'}            | ${'<span id="LC1" lang="bash" class="hljs-code">```bash'}
-    ${'<span class="hljs-code">```bash'}               | ${'valid-language1'} | ${'<span id="LC1" lang="valid-language1" class="hljs-code">```bash'}
-    ${'<span class="hljs-code">```bash'}               | ${'valid_language2'} | ${'<span id="LC1" lang="valid_language2" class="hljs-code">```bash'}
-  `('returns lines wrapped in spans containing line numbers', ({ content, language, output }) => {
-    expect(wrapLines(content, language)).toBe(output);
-  });
-
-  it.each`
-    language
-    ${'invalidLanguage>'}
-    ${'"invalidLanguage"'}
-    ${'<invalidLanguage'}
-  `('returns lines safely without XSS language is not valid', ({ language }) => {
-    expect(wrapLines('<span class="hljs-code">```bash', language)).toBe(
-      '<span id="LC1" lang="" class="hljs-code">```bash',
-    );
-  });
-});
diff --git a/spec/lib/backup/manager_spec.rb b/spec/lib/backup/manager_spec.rb
index 9cf78a11bc7..5e6e6f5594b 100644
--- a/spec/lib/backup/manager_spec.rb
+++ b/spec/lib/backup/manager_spec.rb
@@ -28,7 +28,7 @@ RSpec.describe Backup::Manager do
     it 'calls the named task' do
       expect(task).to receive(:dump)
       expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Dumping my task ... ')
-      expect(Gitlab::BackupLogger).to receive(:info).with(message: 'done')
+      expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Dumping my task ... done')
 
       subject.run_create_task('my_task')
     end
@@ -37,8 +37,7 @@ RSpec.describe Backup::Manager do
       let(:enabled) { false }
 
       it 'informs the user' do
-        expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Dumping my task ... ')
-        expect(Gitlab::BackupLogger).to receive(:info).with(message: '[DISABLED]')
+        expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Dumping my task ... [DISABLED]')
 
         subject.run_create_task('my_task')
       end
@@ -48,8 +47,7 @@ RSpec.describe Backup::Manager do
       it 'informs the user' do
         stub_env('SKIP', 'my_task')
 
-        expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Dumping my task ... ')
-        expect(Gitlab::BackupLogger).to receive(:info).with(message: '[SKIPPED]')
+        expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Dumping my task ... [SKIPPED]')
 
         subject.run_create_task('my_task')
       end
@@ -78,7 +76,7 @@ RSpec.describe Backup::Manager do
     it 'calls the named task' do
       expect(task).to receive(:restore)
       expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Restoring my task ... ').ordered
-      expect(Gitlab::BackupLogger).to receive(:info).with(message: 'done').ordered
+      expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Restoring my task ... done').ordered
 
       subject.run_restore_task('my_task')
     end
@@ -87,8 +85,7 @@ RSpec.describe Backup::Manager do
       let(:enabled) { false }
 
       it 'informs the user' do
-        expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Restoring my task ... ').ordered
-        expect(Gitlab::BackupLogger).to receive(:info).with(message: '[DISABLED]').ordered
+        expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Restoring my task ... [DISABLED]').ordered
 
         subject.run_restore_task('my_task')
       end
@@ -100,7 +97,7 @@ RSpec.describe Backup::Manager do
       it 'displays and waits for the user' do
         expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Restoring my task ... ').ordered
         expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Watch out!').ordered
-        expect(Gitlab::BackupLogger).to receive(:info).with(message: 'done').ordered
+        expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Restoring my task ... done').ordered
         expect(Gitlab::TaskHelpers).to receive(:ask_to_continue)
         expect(task).to receive(:restore)
 
@@ -124,7 +121,7 @@ RSpec.describe Backup::Manager do
 
       it 'displays and waits for the user' do
         expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Restoring my task ... ').ordered
-        expect(Gitlab::BackupLogger).to receive(:info).with(message: 'done').ordered
+        expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Restoring my task ... done').ordered
         expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Watch out!').ordered
         expect(Gitlab::TaskHelpers).to receive(:ask_to_continue)
         expect(task).to receive(:restore)
@@ -134,7 +131,7 @@ RSpec.describe Backup::Manager do
 
       it 'does not continue when the user quits' do
         expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Restoring my task ... ').ordered
-        expect(Gitlab::BackupLogger).to receive(:info).with(message: 'done').ordered
+        expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Restoring my task ... done').ordered
         expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Watch out!').ordered
         expect(Gitlab::BackupLogger).to receive(:info).with(message: 'Quitting...').ordered
         expect(task).to receive(:restore)
@@ -170,7 +167,9 @@ RSpec.describe Backup::Manager do
 
     before do
       allow(ActiveRecord::Base.connection).to receive(:reconnect!)
+      allow(Gitlab::BackupLogger).to receive(:info)
       allow(Kernel).to receive(:system).and_return(true)
+      allow(YAML).to receive(:load_file).and_call_original
       allow(YAML).to receive(:load_file).with(File.join(Gitlab.config.backup.path, 'backup_information.yml'))
         .and_return(backup_information)
 
@@ -185,6 +184,20 @@ RSpec.describe Backup::Manager do
       expect(Kernel).to have_received(:system).with(*tar_cmdline)
     end
 
+    context 'tar fails' do
+      before do
+        expect(Kernel).to receive(:system).with(*tar_cmdline).and_return(false)
+      end
+
+      it 'logs a failure' do
+        expect do
+          subject.create # rubocop:disable Rails/SaveBang
+        end.to raise_error(Backup::Error, 'Backup failed')
+
+        expect(Gitlab::BackupLogger).to have_received(:info).with(message: "Creating archive #{tar_file} failed")
+      end
+    end
+
     context 'when BACKUP is set' do
       let(:tar_file) { 'custom_gitlab_backup.tar' }
 
@@ -248,6 +261,7 @@ RSpec.describe Backup::Manager do
       end
 
       before do
+        allow(Gitlab::BackupLogger).to receive(:info)
         allow(Dir).to receive(:chdir).and_yield
         allow(Dir).to receive(:glob).and_return(files)
         allow(FileUtils).to receive(:rm)
@@ -266,7 +280,7 @@ RSpec.describe Backup::Manager do
         end
 
         it 'prints a skipped message' do
-          expect(progress).to have_received(:puts).with('skipping')
+          expect(Gitlab::BackupLogger).to have_received(:info).with(message: 'Deleting old backups ... [SKIPPED]')
         end
       end
 
@@ -290,7 +304,7 @@ RSpec.describe Backup::Manager do
         end
 
         it 'prints a done message' do
-          expect(progress).to have_received(:puts).with('done. (0 removed)')
+          expect(Gitlab::BackupLogger).to have_received(:info).with(message: 'Deleting old backups ... done. (0 removed)')
         end
       end
 
@@ -307,7 +321,7 @@ RSpec.describe Backup::Manager do
         end
 
         it 'prints a done message' do
-          expect(progress).to have_received(:puts).with('done. (0 removed)')
+          expect(Gitlab::BackupLogger).to have_received(:info).with(message: 'Deleting old backups ... done. (0 removed)')
         end
       end
 
@@ -348,7 +362,7 @@ RSpec.describe Backup::Manager do
         end
 
         it 'prints a done message' do
-          expect(progress).to have_received(:puts).with('done. (8 removed)')
+          expect(Gitlab::BackupLogger).to have_received(:info).with(message: 'Deleting old backups ... done. (8 removed)')
         end
       end
 
@@ -372,11 +386,11 @@ RSpec.describe Backup::Manager do
         end
 
         it 'sets the correct removed count' do
-          expect(progress).to have_received(:puts).with('done. (7 removed)')
+          expect(Gitlab::BackupLogger).to have_received(:info).with(message: 'Deleting old backups ... done. (7 removed)')
         end
 
         it 'prints the error from file that could not be removed' do
-          expect(progress).to have_received(:puts).with(a_string_matching(message))
+          expect(Gitlab::BackupLogger).to have_received(:info).with(message: a_string_matching(message))
         end
       end
     end
@@ -386,6 +400,7 @@ RSpec.describe Backup::Manager do
       let(:backup_filename) { File.basename(backup_file.path) }
 
       before do
+        allow(Gitlab::BackupLogger).to receive(:info)
         allow(subject).to receive(:tar_file).and_return(backup_filename)
 
         stub_backup_setting(
@@ -462,7 +477,7 @@ RSpec.describe Backup::Manager do
           it 'sets encryption attributes' do
             subject.create # rubocop:disable Rails/SaveBang
 
-            expect(progress).to have_received(:puts).with("done (encrypted with AES256)")
+            expect(Gitlab::BackupLogger).to have_received(:info).with(message: 'Uploading backup archive to remote storage directory ... done (encrypted with AES256)')
           end
         end
 
@@ -473,7 +488,7 @@ RSpec.describe Backup::Manager do
           it 'sets encryption attributes' do
             subject.create # rubocop:disable Rails/SaveBang
 
-            expect(progress).to have_received(:puts).with("done (encrypted with AES256)")
+            expect(Gitlab::BackupLogger).to have_received(:info).with(message: 'Uploading backup archive to remote storage directory ... done (encrypted with AES256)')
           end
         end
 
@@ -488,7 +503,7 @@ RSpec.describe Backup::Manager do
           it 'sets encryption attributes' do
             subject.create # rubocop:disable Rails/SaveBang
 
-            expect(progress).to have_received(:puts).with("done (encrypted with aws:kms)")
+            expect(Gitlab::BackupLogger).to have_received(:info).with(message: 'Uploading backup archive to remote storage directory ... done (encrypted with aws:kms)')
           end
         end
       end
@@ -570,6 +585,7 @@ RSpec.describe Backup::Manager do
       Rake.application.rake_require 'tasks/gitlab/shell'
       Rake.application.rake_require 'tasks/cache'
 
+      allow(Gitlab::BackupLogger).to receive(:info)
       allow(task1).to receive(:restore).with(File.join(Gitlab.config.backup.path, 'task1.tar.gz'))
       allow(task2).to receive(:restore).with(File.join(Gitlab.config.backup.path, 'task2.tar.gz'))
       allow(YAML).to receive(:load_file).with(File.join(Gitlab.config.backup.path, 'backup_information.yml'))
@@ -634,7 +650,10 @@ RSpec.describe Backup::Manager do
     end
 
     context 'when BACKUP variable is set to a correct file' do
+      let(:tar_cmdline) { %w{tar -xf 1451606400_2016_01_01_1.2.3_gitlab_backup.tar} }
+
       before do
+        allow(Gitlab::BackupLogger).to receive(:info)
         allow(Dir).to receive(:glob).and_return(
           [
             '1451606400_2016_01_01_1.2.3_gitlab_backup.tar'
@@ -649,8 +668,21 @@ RSpec.describe Backup::Manager do
       it 'unpacks the file' do
         subject.restore
 
-        expect(Kernel).to have_received(:system)
-          .with("tar", "-xf", "1451606400_2016_01_01_1.2.3_gitlab_backup.tar")
+        expect(Kernel).to have_received(:system).with(*tar_cmdline)
+      end
+
+      context 'tar fails' do
+        before do
+          expect(Kernel).to receive(:system).with(*tar_cmdline).and_return(false)
+        end
+
+        it 'logs a failure' do
+          expect do
+            subject.restore
+          end.to raise_error(SystemExit)
+
+          expect(Gitlab::BackupLogger).to have_received(:info).with(message: 'Unpacking backup failed')
+        end
       end
 
       context 'on version mismatch' do
@@ -680,7 +712,7 @@ RSpec.describe Backup::Manager do
 
           subject.restore
 
-          expect(progress).to have_received(:print).with('Deleting backups/tmp ... ')
+          expect(Gitlab::BackupLogger).to have_received(:info).with(message: 'Deleting backups/tmp ... ')
         end
       end
     end
@@ -731,7 +763,7 @@ RSpec.describe Backup::Manager do
 
           subject.restore
 
-          expect(progress).to have_received(:print).with('Deleting backups/tmp ... ')
+          expect(Gitlab::BackupLogger).to have_received(:info).with(message: 'Deleting backups/tmp ... ')
         end
       end
     end
diff --git a/spec/support/helpers/features/invite_members_modal_helper.rb b/spec/support/helpers/features/invite_members_modal_helper.rb
index 2a4f78ca57f..6b7c2dfacac 100644
--- a/spec/support/helpers/features/invite_members_modal_helper.rb
+++ b/spec/support/helpers/features/invite_members_modal_helper.rb
@@ -43,6 +43,18 @@ module Spec
 
             fill_in 'YYYY-MM-DD', with: expires_at.strftime('%Y-%m-%d') if expires_at
           end
+
+          def group_dropdown_selector
+            '[data-testid="group-select-dropdown"]'
+          end
+
+          def expect_to_have_group(group)
+            expect(page).to have_selector("[entity-id='#{group.id}']")
+          end
+
+          def expect_not_to_have_group(group)
+            expect(page).not_to have_selector("[entity-id='#{group.id}']")
+          end
         end
       end
     end
diff --git a/spec/support/shared_examples/lib/gitlab/event_store_shared_examples.rb b/spec/support/shared_examples/lib/gitlab/event_store_shared_examples.rb
new file mode 100644
index 00000000000..4fc15cacab4
--- /dev/null
+++ b/spec/support/shared_examples/lib/gitlab/event_store_shared_examples.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+RSpec.shared_examples 'subscribes to event' do
+  include AfterNextHelpers
+
+  it 'consumes the published event', :sidekiq_inline do
+    expect_next(described_class)
+      .to receive(:handle_event)
+      .with(instance_of(event.class))
+      .and_call_original
+
+    ::Gitlab::EventStore.publish(event)
+  end
+end
+
+def consume_event(subscriber:, event:)
+  subscriber.new.perform(event.class.name, event.data)
+end
diff --git a/spec/tasks/gitlab/backup_rake_spec.rb b/spec/tasks/gitlab/backup_rake_spec.rb
index df9f2a0d3bb..da6d4c2ad08 100644
--- a/spec/tasks/gitlab/backup_rake_spec.rb
+++ b/spec/tasks/gitlab/backup_rake_spec.rb
@@ -199,18 +199,25 @@ RSpec.describe 'gitlab:app namespace rake task', :delete do
         end
 
         it 'logs the progress to log file' do
-          expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping database ... ")
-          expect(Gitlab::BackupLogger).to receive(:info).with(message: "[SKIPPED]")
+          expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping database ... [SKIPPED]")
           expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping repositories ... ")
+          expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping repositories ... done")
           expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping uploads ... ")
+          expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping uploads ... done")
           expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping builds ... ")
+          expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping builds ... done")
           expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping artifacts ... ")
+          expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping artifacts ... done")
           expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping pages ... ")
+          expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping pages ... done")
           expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping lfs objects ... ")
+          expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping lfs objects ... done")
           expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping terraform states ... ")
+          expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping terraform states ... done")
           expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping container registry images ... ")
+          expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping container registry images ... done")
           expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping packages ... ")
-          expect(Gitlab::BackupLogger).to receive(:info).with(message: "done").exactly(9).times
+          expect(Gitlab::BackupLogger).to receive(:info).with(message: "Dumping packages ... done")
 
           backup_tasks.each do |task|
             run_rake_task("gitlab:backup:#{task}:create")
diff --git a/spec/workers/merge_requests/update_head_pipeline_worker_spec.rb b/spec/workers/merge_requests/update_head_pipeline_worker_spec.rb
index f3ea14ad539..5e0b07067df 100644
--- a/spec/workers/merge_requests/update_head_pipeline_worker_spec.rb
+++ b/spec/workers/merge_requests/update_head_pipeline_worker_spec.rb
@@ -11,11 +11,9 @@ RSpec.describe MergeRequests::UpdateHeadPipelineWorker do
   let(:pipeline) { create(:ci_pipeline, project: project, ref: ref) }
   let(:event) { Ci::PipelineCreatedEvent.new(data: { pipeline_id: pipeline.id }) }
 
-  subject { consume_event(event) }
+  subject { consume_event(subscriber: described_class, event: event) }
 
-  def consume_event(event)
-    described_class.new.perform(event.class.name, event.data)
-  end
+  it_behaves_like 'subscribes to event'
 
   context 'when merge requests already exist for this source branch', :sidekiq_inline do
     let(:merge_request_1) do
diff --git a/spec/workers/namespaces/update_root_statistics_worker_spec.rb b/spec/workers/namespaces/update_root_statistics_worker_spec.rb
index a525904b757..f2f633a39ca 100644
--- a/spec/workers/namespaces/update_root_statistics_worker_spec.rb
+++ b/spec/workers/namespaces/update_root_statistics_worker_spec.rb
@@ -9,11 +9,9 @@ RSpec.describe Namespaces::UpdateRootStatisticsWorker do
     Projects::ProjectDeletedEvent.new(data: { project_id: 1, namespace_id: namespace_id })
   end
 
-  subject { consume_event(event) }
+  subject { consume_event(subscriber: described_class, event: event) }
 
-  def consume_event(event)
-    described_class.new.perform(event.class.name, event.data)
-  end
+  it_behaves_like 'subscribes to event'
 
   it 'enqueues ScheduleAggregationWorker' do
     expect(Namespaces::ScheduleAggregationWorker).to receive(:perform_async).with(namespace_id)