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authorStan Hu <stanhu@gmail.com>2017-11-16 16:14:24 -0800
committerSean McGivern <sean@gitlab.com>2017-11-17 10:23:48 +0000
commit5cecff893db3188ff5ec779e07e9c598d3ed2e21 (patch)
tree33b5957717da5d0add5356c4db8e65650f9fb1ae /db
parentd41e66cb632cf4a51428c87a07cbdd182e3e0697 (diff)
downloadgitlab-ce-5cecff893db3188ff5ec779e07e9c598d3ed2e21.tar.gz
Convert migration to populate latest merge request ID into a background migration
This is to smear updates over a few hours to avoid causing excessive replication lag as seen in https://gitlab.com/gitlab-com/infrastructure/issues/3235.
Diffstat (limited to 'db')
-rw-r--r--db/post_migrate/20171026082505_populate_merge_requests_latest_merge_request_diff_id.rb27
-rw-r--r--db/post_migrate/20171026082505_schedule_merge_request_latest_merge_request_diff_id_migrations.rb29
2 files changed, 29 insertions, 27 deletions
diff --git a/db/post_migrate/20171026082505_populate_merge_requests_latest_merge_request_diff_id.rb b/db/post_migrate/20171026082505_populate_merge_requests_latest_merge_request_diff_id.rb
deleted file mode 100644
index a7ebbbf34c0..00000000000
--- a/db/post_migrate/20171026082505_populate_merge_requests_latest_merge_request_diff_id.rb
+++ /dev/null
@@ -1,27 +0,0 @@
-class PopulateMergeRequestsLatestMergeRequestDiffId < ActiveRecord::Migration
- include Gitlab::Database::MigrationHelpers
-
- DOWNTIME = false
- BATCH_SIZE = 1_000
-
- class MergeRequest < ActiveRecord::Base
- self.table_name = 'merge_requests'
-
- include ::EachBatch
- end
-
- disable_ddl_transaction!
-
- def up
- update = '
- latest_merge_request_diff_id = (
- SELECT MAX(id)
- FROM merge_request_diffs
- WHERE merge_requests.id = merge_request_diffs.merge_request_id
- )'.squish
-
- MergeRequest.where(latest_merge_request_diff_id: nil).each_batch(of: BATCH_SIZE) do |relation|
- relation.update_all(update)
- end
- end
-end
diff --git a/db/post_migrate/20171026082505_schedule_merge_request_latest_merge_request_diff_id_migrations.rb b/db/post_migrate/20171026082505_schedule_merge_request_latest_merge_request_diff_id_migrations.rb
new file mode 100644
index 00000000000..7a63382cc6d
--- /dev/null
+++ b/db/post_migrate/20171026082505_schedule_merge_request_latest_merge_request_diff_id_migrations.rb
@@ -0,0 +1,29 @@
+class ScheduleMergeRequestLatestMergeRequestDiffIdMigrations < ActiveRecord::Migration
+ include Gitlab::Database::MigrationHelpers
+
+ DOWNTIME = false
+ BATCH_SIZE = 50_000
+ MIGRATION = 'PopulateMergeRequestsLatestMergeRequestDiffId'
+
+ disable_ddl_transaction!
+
+ class MergeRequest < ActiveRecord::Base
+ self.table_name = 'merge_requests'
+
+ include ::EachBatch
+ end
+
+ # On GitLab.com, we saw that we generated about 500,000 dead tuples over 5 minutes.
+ # To keep replication lag from ballooning, we'll aim for 50,000 updates over 5 minutes.
+ #
+ # Assuming that there are 5 million rows affected (which is more than on
+ # GitLab.com), and that each batch of 50,000 rows takes up to 5 minutes, then
+ # we can migrate all the rows in 8.5 hours.
+ def up
+ MergeRequest.where(latest_merge_request_diff_id: nil).each_batch(of: BATCH_SIZE) do |relation, index|
+ range = relation.pluck('MIN(id)', 'MAX(id)').first
+
+ BackgroundMigrationWorker.perform_in(index * 5.minutes, MIGRATION, range)
+ end
+ end
+end