From eb086a4bfd2495168483a2652571f247e6b768a5 Mon Sep 17 00:00:00 2001
From: Sean McGivern <sean@gitlab.com>
Date: Tue, 19 Jun 2018 17:18:15 +0100
Subject: Disallow methods that copy data on large tables

{change_column_type,rename_column}_concurrently both copy data from one column
to another during a migration, which should not be done on GitLab.com. Instead,
we should use background migrations.
---
 rubocop/cop/migration/update_large_table.rb          |  9 ++++++++-
 .../rubocop/cop/migration/update_large_table_spec.rb | 20 ++++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/rubocop/cop/migration/update_large_table.rb b/rubocop/cop/migration/update_large_table.rb
index bb14d0f4f56..e3e3de0a4d7 100644
--- a/rubocop/cop/migration/update_large_table.rb
+++ b/rubocop/cop/migration/update_large_table.rb
@@ -34,8 +34,15 @@ module RuboCop
           users
         ].freeze
 
+        BATCH_UPDATE_METHODS = %w[
+          :add_column_with_default
+          :change_column_type_concurrently
+          :rename_column_concurrently
+          :update_column_in_batches
+        ].join(' ').freeze
+
         def_node_matcher :batch_update?, <<~PATTERN
-          (send nil? ${:add_column_with_default :update_column_in_batches} $(sym ...) ...)
+          (send nil? ${#{BATCH_UPDATE_METHODS}} $(sym ...) ...)
         PATTERN
 
         def on_send(node)
diff --git a/spec/rubocop/cop/migration/update_large_table_spec.rb b/spec/rubocop/cop/migration/update_large_table_spec.rb
index ef724fc8bad..5e08eb4f772 100644
--- a/spec/rubocop/cop/migration/update_large_table_spec.rb
+++ b/spec/rubocop/cop/migration/update_large_table_spec.rb
@@ -32,6 +32,14 @@ describe RuboCop::Cop::Migration::UpdateLargeTable do
       include_examples 'large tables', 'add_column_with_default'
     end
 
+    context 'for the change_column_type_concurrently method' do
+      include_examples 'large tables', 'change_column_type_concurrently'
+    end
+
+    context 'for the rename_column_concurrently method' do
+      include_examples 'large tables', 'rename_column_concurrently'
+    end
+
     context 'for the update_column_in_batches method' do
       include_examples 'large tables', 'update_column_in_batches'
     end
@@ -60,6 +68,18 @@ describe RuboCop::Cop::Migration::UpdateLargeTable do
       expect(cop.offenses).to be_empty
     end
 
+    it 'registers no offense for change_column_type_concurrently' do
+      inspect_source("change_column_type_concurrently :#{table}, :column, default: true")
+
+      expect(cop.offenses).to be_empty
+    end
+
+    it 'registers no offense for update_column_in_batches' do
+      inspect_source("rename_column_concurrently :#{table}, :column, default: true")
+
+      expect(cop.offenses).to be_empty
+    end
+
     it 'registers no offense for update_column_in_batches' do
       inspect_source("add_column_with_default :#{table}, :column, default: true")
 
-- 
cgit v1.2.1


From 03ccd39a0ccafe79df50702464ff02d3ca0312c4 Mon Sep 17 00:00:00 2001
From: Sean McGivern <sean@gitlab.com>
Date: Fri, 22 Jun 2018 11:09:46 +0100
Subject: Add more large tables to cop

These are all over 20 GB on GitLab.com. merge_request_diff_commits is several
hundred gigabytes in size.
---
 rubocop/cop/migration/update_large_table.rb | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/rubocop/cop/migration/update_large_table.rb b/rubocop/cop/migration/update_large_table.rb
index e3e3de0a4d7..c15eec22d04 100644
--- a/rubocop/cop/migration/update_large_table.rb
+++ b/rubocop/cop/migration/update_large_table.rb
@@ -20,10 +20,14 @@ module RuboCop
               'necessary'.freeze
 
         LARGE_TABLES = %i[
-          ci_pipelines
+          ci_build_trace_sections
           ci_builds
+          ci_job_artifacts
+          ci_pipelines
+          ci_stages
           events
           issues
+          merge_request_diff_commits
           merge_request_diff_files
           merge_request_diffs
           merge_requests
-- 
cgit v1.2.1