Merge branch '36631-activerecord-statementinvalid-pg-querycanceled-error-canceling-statement-due-to-statement-timeout' into 'master'

Insert at most 1,000 rows at once in MR diff background migration

Closes #36631 et #37505

See merge request gitlab-org/gitlab-ce!13661

1 files changed, 32 insertions, 0 deletions

diff --git a/db/post_migrate/20170926150348_schedule_merge_request_diff_migrations_take_two.rb b/db/post_migrate/20170926150348_schedule_merge_request_diff_migrations_take_two.rb
new file mode 100644
index 00000000000..5732cb85ea5
--- /dev/null
+++ b/db/post_migrate/20170926150348_schedule_merge_request_diff_migrations_take_two.rb
@@ -0,0 +1,32 @@
+class ScheduleMergeRequestDiffMigrationsTakeTwo < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  BATCH_SIZE = 500
+  MIGRATION = 'DeserializeMergeRequestDiffsAndCommits'
+  DELAY_INTERVAL = 10.minutes
+
+  disable_ddl_transaction!
+
+  class MergeRequestDiff < ActiveRecord::Base
+    self.table_name = 'merge_request_diffs'
+
+    include ::EachBatch
+
+    default_scope { where('st_commits IS NOT NULL OR st_diffs IS NOT NULL') }
+  end
+
+  # By this point, we assume ScheduleMergeRequestDiffMigrations - the first
+  # version of this - has already run. On GitLab.com, we have ~220k un-migrated
+  # rows, but these rows will, in general, take a long time.
+  #
+  # With a gap of 10 minutes per batch, and 500 rows per batch, these migrations
+  # are scheduled over 220_000 / 500 / 6 ~= 74 hours, which is a little over
+  # three days.
+  def up
+    queue_background_migration_jobs_by_range_at_intervals(MergeRequestDiff, MIGRATION, DELAY_INTERVAL, batch_size: BATCH_SIZE)
+  end
+
+  def down
+  end
+end