Add pause control strategy for ClickHouse migrations (8df7708c) · Commits · GitLab.org / GitLab

app/workers/click_house/events_sync_worker.rb

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		@@ -3,6 +3,7 @@
		module ClickHouse
		class EventsSyncWorker
		include ApplicationWorker
		include ClickHouseWorker
		include Gitlab::ExclusiveLeaseHelpers
		include Gitlab::Utils::StrongMemoize

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		# frozen_string_literal: true

		module ClickHouseWorker
		extend ActiveSupport::Concern

		class_methods do
		def register_click_house_worker?
		click_house_worker_attrs.present?
		end

		def click_house_worker_attrs
		get_class_attribute(:click_house_worker_attrs)
		end

		def click_house_migration_lock(ttl)
		raise ArgumentError unless ttl.is_a?(ActiveSupport::Duration)

		set_class_attribute(
		:click_house_worker_attrs,
		(click_house_worker_attrs \|\| {}).merge(migration_lock_ttl: ttl)
		)
		end
		end

		included do
		click_house_migration_lock(ClickHouse::MigrationSupport::ExclusiveLock::DEFAULT_CLICKHOUSE_WORKER_TTL)

		pause_control :click_house_migration
		end
		end

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		---
		name: pause_clickhouse_workers_during_migration
		introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/138166
		rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/433389
		milestone: '16.7'
		type: development
		group: group::runner
		default_enabled: false

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		---
		name: wait_for_clickhouse_workers_during_migration
		introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/138166
		rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/433389
		milestone: '16.7'
		type: development
		group: group::runner
		default_enabled: false

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		@@ -205,6 +205,26 @@ end
		NOTE:
		It's important to test and verify efficient batching of database records from PostgreSQL. Consider using the techniques described in the [Iterating tables in batches](../iterating_tables_in_batches.md).

		## Implementing Sidekiq workers

		Sidekiq workers leveraging ClickHouse databases should include the `ClickHouseWorker` module.
		This ensures that the worker is paused while database migrations are running,
		and that migrations do not run while the worker is active.

		```ruby
		# events_sync_worker.rb
		# frozen_string_literal: true

		module ClickHouse
		class EventsSyncWorker
		include ApplicationWorker
		include ClickHouseWorker

		...
		end
		end
		```

		## Testing

		ClickHouse is enabled on CI/CD but to avoid significantly affecting the pipeline runtime we've decided to run the ClickHouse server for test cases tagged with `:click_house` only.