Remove dead MySQL code

None of this code can be reached any more, so it can all be removed

4 files changed, 13 insertions, 53 deletions

diff --git a/db/post_migrate/20180409170809_populate_missing_project_ci_cd_settings.rb b/db/post_migrate/20180409170809_populate_missing_project_ci_cd_settings.rb
index 0cda3d76a3d..a400a071e07 100644
--- a/db/post_migrate/20180409170809_populate_missing_project_ci_cd_settings.rb
+++ b/db/post_migrate/20180409170809_populate_missing_project_ci_cd_settings.rb
@@ -9,10 +9,6 @@ class PopulateMissingProjectCiCdSettings < ActiveRecord::Migration[4.2]
   disable_ddl_transaction!
 
   def up
-    # MySQL does not support online upgrades, thus there can't be any missing
-    # rows.
-    return if Gitlab::Database.mysql?
-
     # Projects created after the initial migration but before the code started
     # using ProjectCiCdSetting won't have a corresponding row in
     # project_ci_cd_settings, so let's fix that.
diff --git a/db/post_migrate/20181219130552_update_project_import_visibility_level.rb b/db/post_migrate/20181219130552_update_project_import_visibility_level.rb
index 6209de88b31..bfa452578a3 100644
--- a/db/post_migrate/20181219130552_update_project_import_visibility_level.rb
+++ b/db/post_migrate/20181219130552_update_project_import_visibility_level.rb
@@ -49,7 +49,7 @@ class UpdateProjectImportVisibilityLevel < ActiveRecord::Migration[5.0]
   def update_projects_visibility(visibility)
     say_with_time("Updating project visibility to #{visibility} on #{Project::IMPORT_TYPE} imports.") do
       Project.with_group_visibility(visibility).select(:id).each_batch(of: BATCH_SIZE) do |batch, _index|
-        batch_sql = Gitlab::Database.mysql? ? batch.pluck(:id).join(', ') : batch.select(:id).to_sql
+        batch_sql = batch.select(:id).to_sql
 
         say("Updating #{batch.size} items.", true)
 
diff --git a/db/post_migrate/20190204115450_migrate_auto_dev_ops_domain_to_cluster_domain.rb b/db/post_migrate/20190204115450_migrate_auto_dev_ops_domain_to_cluster_domain.rb
index 392e64eeade..036b0b64b48 100644
--- a/db/post_migrate/20190204115450_migrate_auto_dev_ops_domain_to_cluster_domain.rb
+++ b/db/post_migrate/20190204115450_migrate_auto_dev_ops_domain_to_cluster_domain.rb
@@ -16,26 +16,6 @@ class MigrateAutoDevOpsDomainToClusterDomain < ActiveRecord::Migration[5.0]
   private
 
   def update_clusters_domain_query
-    if Gitlab::Database.mysql?
-      mysql_query
-    else
-      postgresql_query
-    end
-  end
-
-  def mysql_query
-    <<~HEREDOC
-    UPDATE clusters, project_auto_devops, cluster_projects
-    SET
-      clusters.domain = project_auto_devops.domain
-    WHERE
-      cluster_projects.cluster_id = clusters.id
-      AND project_auto_devops.project_id = cluster_projects.project_id
-      AND project_auto_devops.domain != ''
-    HEREDOC
-  end
-
-  def postgresql_query
     <<~HEREDOC
     UPDATE clusters
     SET domain = project_auto_devops.domain
diff --git a/db/post_migrate/20190404143330_add_unique_constraint_to_approvals_user_id_and_merge_request_id.rb b/db/post_migrate/20190404143330_add_unique_constraint_to_approvals_user_id_and_merge_request_id.rb
index 447f91ebc7e..dd85ebc8001 100644
--- a/db/post_migrate/20190404143330_add_unique_constraint_to_approvals_user_id_and_merge_request_id.rb
+++ b/db/post_migrate/20190404143330_add_unique_constraint_to_approvals_user_id_and_merge_request_id.rb
@@ -21,34 +21,18 @@ class AddUniqueConstraintToApprovalsUserIdAndMergeRequestId < ActiveRecord::Migr
   def remove_duplicates
     add_concurrent_index :approvals, [:user_id, :merge_request_id, :id]
 
-    if Gitlab::Database.mysql?
-      execute <<-SQL
-        DELETE FROM a
-        USING approvals AS a
-        INNER JOIN (
-          SELECT user_id, merge_request_id, MIN(id) as min_id
-          FROM approvals
-          GROUP BY user_id, merge_request_id
-          HAVING COUNT(id) > 1
-        ) as approvals_with_duplicates
-        ON approvals_with_duplicates.user_id = a.user_id
-        AND approvals_with_duplicates.merge_request_id = a.merge_request_id
-        WHERE approvals_with_duplicates.min_id <> a.id;
-      SQL
-    else
-      execute <<-SQL
-        DELETE FROM approvals
-        USING (
-          SELECT user_id, merge_request_id, MIN(id) as min_id
-          FROM approvals
-          GROUP BY user_id, merge_request_id
-          HAVING COUNT(id) > 1
-        ) as approvals_with_duplicates
-        WHERE approvals_with_duplicates.user_id = approvals.user_id
-        AND approvals_with_duplicates.merge_request_id = approvals.merge_request_id
-        AND approvals_with_duplicates.min_id <> approvals.id;
-      SQL
-    end
+    execute <<-SQL
+      DELETE FROM approvals
+      USING (
+        SELECT user_id, merge_request_id, MIN(id) as min_id
+        FROM approvals
+        GROUP BY user_id, merge_request_id
+        HAVING COUNT(id) > 1
+      ) as approvals_with_duplicates
+      WHERE approvals_with_duplicates.user_id = approvals.user_id
+      AND approvals_with_duplicates.merge_request_id = approvals.merge_request_id
+      AND approvals_with_duplicates.min_id <> approvals.id;
+    SQL
 
     remove_concurrent_index :approvals, [:user_id, :merge_request_id, :id]
   end