Improve epic inherited dates update performance7332-inherit-epic-dates-ce

* Uses a single update statement to update start_date, due_date,
start_date_sourcing_milestone_id, start_date_sourcing_epic_id,
due_date_sourcing_milestone_id, due_date_sourcing_epic_id
* Moves inherited dates update of multiple epics to an async worker

5 files changed, 8 insertions, 7 deletions

diff --git a/config/sidekiq_queues.yml b/config/sidekiq_queues.yml
index ea165508d29..92fbdc46fc1 100644
--- a/config/sidekiq_queues.yml
+++ b/config/sidekiq_queues.yml
@@ -114,3 +114,4 @@
   - [export_csv, 1]
   - [incident_management, 2]
   - [jira_connect, 1]
+  - [update_epics_dates, 2]
diff --git a/lib/gitlab/sql/union.rb b/lib/gitlab/sql/union.rb
index f05592fc3a3..4c9e0cd5cdf 100644
--- a/lib/gitlab/sql/union.rb
+++ b/lib/gitlab/sql/union.rb
@@ -29,7 +29,7 @@ module Gitlab
         end
 
         if fragments.any?
-          fragments.join("\n#{union_keyword}\n")
+          fragments.join(")\n#{union_keyword}\n(").prepend('(').concat(')')
         else
           'NULL'
         end
diff --git a/spec/lib/gitlab/sql/recursive_cte_spec.rb b/spec/lib/gitlab/sql/recursive_cte_spec.rb
index 407a4d8a247..d45bc67e4a1 100644
--- a/spec/lib/gitlab/sql/recursive_cte_spec.rb
+++ b/spec/lib/gitlab/sql/recursive_cte_spec.rb
@@ -18,7 +18,7 @@ describe Gitlab::SQL::RecursiveCTE do
         [rel1.except(:order).to_sql, rel2.except(:order).to_sql]
       end
 
-      expect(sql).to eq("#{name} AS (#{sql1}\nUNION\n#{sql2})")
+      expect(sql).to eq("#{name} AS ((#{sql1})\nUNION\n(#{sql2}))")
     end
   end
 
diff --git a/spec/lib/gitlab/sql/union_spec.rb b/spec/lib/gitlab/sql/union_spec.rb
index fe6422c32b6..b77bd3a1d2a 100644
--- a/spec/lib/gitlab/sql/union_spec.rb
+++ b/spec/lib/gitlab/sql/union_spec.rb
@@ -12,7 +12,7 @@ describe Gitlab::SQL::Union do
     it 'returns a String joining relations together using a UNION' do
       union = described_class.new([relation_1, relation_2])
 
-      expect(union.to_sql).to eq("#{to_sql(relation_1)}\nUNION\n#{to_sql(relation_2)}")
+      expect(union.to_sql).to eq("(#{to_sql(relation_1)})\nUNION\n(#{to_sql(relation_2)})")
     end
 
     it 'skips Model.none segements' do
@@ -20,7 +20,7 @@ describe Gitlab::SQL::Union do
       union = described_class.new([empty_relation, relation_1, relation_2])
 
       expect {User.where("users.id IN (#{union.to_sql})").to_a}.not_to raise_error
-      expect(union.to_sql).to eq("#{to_sql(relation_1)}\nUNION\n#{to_sql(relation_2)}")
+      expect(union.to_sql).to eq("(#{to_sql(relation_1)})\nUNION\n(#{to_sql(relation_2)})")
     end
 
     it 'uses UNION ALL when removing duplicates is disabled' do
diff --git a/spec/models/concerns/from_union_spec.rb b/spec/models/concerns/from_union_spec.rb
index ee427a667c6..735e14b47ec 100644
--- a/spec/models/concerns/from_union_spec.rb
+++ b/spec/models/concerns/from_union_spec.rb
@@ -15,7 +15,7 @@ describe FromUnion do
     it 'selects from the results of the UNION' do
       query = model.from_union([model.where(id: 1), model.where(id: 2)])
 
-      expect(query.to_sql).to match(/FROM \(SELECT.+UNION.+SELECT.+\) users/m)
+      expect(query.to_sql).to match(/FROM \(\(SELECT.+\)\nUNION\n\(SELECT.+\)\) users/m)
     end
 
     it 'supports the use of a custom alias for the sub query' do
@@ -24,7 +24,7 @@ describe FromUnion do
         alias_as: 'kittens'
       )
 
-      expect(query.to_sql).to match(/FROM \(SELECT.+UNION.+SELECT.+\) kittens/m)
+      expect(query.to_sql).to match(/FROM \(\(SELECT.+\)\nUNION\n\(SELECT.+\)\) kittens/m)
     end
 
     it 'supports keeping duplicate rows' do
@@ -34,7 +34,7 @@ describe FromUnion do
       )
 
       expect(query.to_sql)
-        .to match(/FROM \(SELECT.+UNION ALL.+SELECT.+\) users/m)
+        .to match(/FROM \(\(SELECT.+\)\nUNION ALL\n\(SELECT.+\)\) users/m)
     end
   end
 end