diff --git a/db/migrate/20220316022508_backfill_namespace_details.rb b/db/migrate/20220316022508_backfill_namespace_details.rb
new file mode 100644
index 0000000000000000000000000000000000000000..eda9b135d44b74d51fb954e57a8798c1f5db5e7b
--- /dev/null
+++ b/db/migrate/20220316022508_backfill_namespace_details.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+class BackfillNamespaceDetails < Gitlab::Database::Migration[1.0]
+  disable_ddl_transaction!
+
+  MIGRATION = 'BackfillNamespaceDetails'
+  INTERVAL = 2.minutes
+  BATCH_SIZE = 1_000
+  MAX_BATCH_SIZE = 2_000
+  SUB_BATCH_SIZE = 200
+
+  def up
+    queue_batched_background_migration(
+      MIGRATION,
+      :namespaces,
+      :id,
+      job_interval: INTERVAL,
+      batch_size: BATCH_SIZE,
+      max_batch_size: MAX_BATCH_SIZE,
+      sub_batch_size: SUB_BATCH_SIZE
+    )
+  end
+
+  def down
+    delete_batched_background_migration(MIGRATION, :namespaces, :id, [])
+  end
+end
diff --git a/db/migrate/20220406011508_backfill_project_namespace_details.rb b/db/migrate/20220406011508_backfill_project_namespace_details.rb
new file mode 100644
index 0000000000000000000000000000000000000000..a2501d40b5d2b7a753f5037020bffe801aae6c45
--- /dev/null
+++ b/db/migrate/20220406011508_backfill_project_namespace_details.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+class BackfillProjectNamespaceDetails < Gitlab::Database::Migration[1.0]
+  disable_ddl_transaction!
+
+  MIGRATION = 'BackfillProjectNamespaceDetails'
+  INTERVAL = 2.minutes
+  BATCH_SIZE = 1_000
+  MAX_BATCH_SIZE = 2_000
+  SUB_BATCH_SIZE = 200
+
+  def up
+    queue_batched_background_migration(
+      MIGRATION,
+      :projects,
+      :id,
+      job_interval: INTERVAL,
+      batch_size: BATCH_SIZE,
+      max_batch_size: MAX_BATCH_SIZE,
+      sub_batch_size: SUB_BATCH_SIZE
+    )
+  end
+
+  def down
+    delete_batched_background_migration(MIGRATION, :projects, :id, [])
+  end
+end
diff --git a/db/schema_migrations/20220316022508 b/db/schema_migrations/20220316022508
new file mode 100644
index 0000000000000000000000000000000000000000..06734edec8d1f0323c3e48cb2298275029bbca28
--- /dev/null
+++ b/db/schema_migrations/20220316022508
@@ -0,0 +1 @@
+0f4487bcba4e60c442e477e05037d05d4cb36fe5cc88445d4d2021e14a193fc5
\ No newline at end of file
diff --git a/db/schema_migrations/20220406011508 b/db/schema_migrations/20220406011508
new file mode 100644
index 0000000000000000000000000000000000000000..e35d7fee09edf7a7085bc9346e7af5baee8f0f28
--- /dev/null
+++ b/db/schema_migrations/20220406011508
@@ -0,0 +1 @@
+a3c1a618e4b7e16b425fb5624db3f78fe053a72ff5273956d88320fbb3f3ecb3
\ No newline at end of file
diff --git a/lib/gitlab/background_migration/backfill_namespace_details.rb b/lib/gitlab/background_migration/backfill_namespace_details.rb
new file mode 100644
index 0000000000000000000000000000000000000000..431557a67cd719359ffbe880fc0d7a198800722f
--- /dev/null
+++ b/lib/gitlab/background_migration/backfill_namespace_details.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # Backfill namespace_details for a range of namespaces
+    class BackfillNamespaceDetails
+      def perform(start_id, end_id)
+        ActiveRecord::Base.connection.execute <<~SQL
+            INSERT INTO namespace_details (description, description_html, cached_markdown_version, created_at, updated_at, namespace_id)
+              SELECT namespaces.description, namespaces.description_html, namespaces.cached_markdown_version, now(), now(), namespaces.id  
+              FROM namespaces
+              WHERE namespaces.id BETWEEN #{start_id} AND #{end_id}
+              AND namespaces.type <> 'Project'
+            ON CONFLICT (namespace_id) DO NOTHING;
+        SQL
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/background_migration/backfill_project_namespace_details.rb b/lib/gitlab/background_migration/backfill_project_namespace_details.rb
new file mode 100644
index 0000000000000000000000000000000000000000..fd08895f58c24de676056730438da016dc9d1d01
--- /dev/null
+++ b/lib/gitlab/background_migration/backfill_project_namespace_details.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # Backfill project_namespace namespace_details for a range of project namespaces
+    class BackfillProjectNamespaceDetails
+      def perform(start_id, end_id)
+        ActiveRecord::Base.connection.execute <<~SQL
+          INSERT INTO namespace_details (description, description_html, cached_markdown_version, created_at, updated_at, namespace_id)
+            SELECT  projects.description, projects.description_html, projects.cached_markdown_version, now(), now(), projects.project_namespace_id
+            FROM projects
+            WHERE projects.project_namespace_id BETWEEN #{start_id} AND #{end_id}
+          ON CONFLICT (namespace_id) DO NOTHING;
+        SQL
+      end
+    end
+  end
+end
diff --git a/spec/lib/gitlab/background_migration/backfill_namespace_details_spec.rb b/spec/lib/gitlab/background_migration/backfill_namespace_details_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..cacb3509d9aa73a2e6c29ac5c3a215af09bcefc3
--- /dev/null
+++ b/spec/lib/gitlab/background_migration/backfill_namespace_details_spec.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require_migration!
+
+RSpec.describe Gitlab::BackgroundMigration::BackfillNamespaceDetails do
+  let(:namespaces) { table(:namespaces) }
+  let(:namespace_details) { table(:namespace_details) }
+  let(:namespace) { table(:namespaces).create!(name: 'user', path: 'user') }
+
+  subject { described_class.new }
+
+  describe '#perform' do
+    it 'creates details for all namespaces in range' do
+      namespaces.create!(id: 5, name: 'test1', path: 'test1')
+      namespaces.create!(id: 6, name: 'test2', path: 'test2', type: 'Project')
+      namespaces.create!(id: 7, name: 'test3', path: 'test3')
+      namespaces.create!(id: 8, name: 'test4', path: 'test4')
+
+      subject.perform(5, 7)
+
+      expect(namespace_details.pluck(:namespace_id)).to contain_exactly(5, 7)
+    end
+  end
+end
diff --git a/spec/lib/gitlab/background_migration/backfill_project_namespace_details_spec.rb b/spec/lib/gitlab/background_migration/backfill_project_namespace_details_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..1256a3738a16d8908e33f767fd05b19c5cb579fb
--- /dev/null
+++ b/spec/lib/gitlab/background_migration/backfill_project_namespace_details_spec.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require_migration!
+
+# rubocop:disable RSpec/FactoriesInMigrationSpecs
+RSpec.describe Gitlab::BackgroundMigration::BackfillProjectNamespaceDetails do
+  let(:namespace_details) { table(:namespace_details) }
+  let(:namespaces) { table(:namespaces) }
+
+  subject { described_class.new }
+
+  describe '#perform' do
+    let(:project_namespace1) { create(:project_namespace) }
+    let(:project_namespace2) { create(:project_namespace) }
+    let(:project_namespace3) { create(:project_namespace) }
+
+    it 'creates details for all project namespaces in range' do
+      subject.perform(project_namespace1.id, project_namespace2.id)
+
+      expect(namespace_details.pluck(:namespace_id) & namespaces.all.where(type: "Project").pluck(:id))
+      .to contain_exactly(project_namespace1.id, project_namespace2.id)
+    end
+  end
+end