forked from treehouse/mastodon
999 lines
36 KiB
Ruby
999 lines
36 KiB
Ruby
# frozen_string_literal: true
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# This file is copied almost entirely from GitLab, which has done a large
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# amount of work to ensure that migrations can happen with minimal downtime.
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# Many thanks to those engineers.
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# Changes have been made to remove dependencies on other GitLab files and to
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# shorten temporary column names.
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# Documentation on using these functions (and why one might do so):
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# https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/what_requires_downtime.md
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# The file itself:
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# https://gitlab.com/gitlab-org/gitlab-ce/blob/master/lib/gitlab/database/migration_helpers.rb
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# It is licensed as follows:
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# Copyright (c) 2011-2017 GitLab B.V.
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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# This is bad form, but there are enough differences that it's impractical to do
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# otherwise:
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# rubocop:disable all
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module Mastodon
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module MigrationHelpers
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# Stub for Database.postgresql? from GitLab
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def self.postgresql?
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ActiveRecord::Base.configurations[Rails.env]['adapter'].casecmp('postgresql').zero?
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end
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# Stub for Database.mysql? from GitLab
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def self.mysql?
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ActiveRecord::Base.configurations[Rails.env]['adapter'].casecmp('mysql2').zero?
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end
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# Model that can be used for querying permissions of a SQL user.
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class Grant < ActiveRecord::Base
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self.table_name =
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if Mastodon::MigrationHelpers.postgresql?
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'information_schema.role_table_grants'
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else
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'mysql.user'
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end
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def self.scope_to_current_user
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if Mastodon::MigrationHelpers.postgresql?
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where('grantee = user')
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else
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where("CONCAT(User, '@', Host) = current_user()")
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end
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end
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# Returns true if the current user can create and execute triggers on the
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# given table.
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def self.create_and_execute_trigger?(table)
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priv =
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if Mastodon::MigrationHelpers.postgresql?
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where(privilege_type: 'TRIGGER', table_name: table)
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else
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where(Trigger_priv: 'Y')
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end
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priv.scope_to_current_user.any?
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end
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end
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BACKGROUND_MIGRATION_BATCH_SIZE = 1000 # Number of rows to process per job
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BACKGROUND_MIGRATION_JOB_BUFFER_SIZE = 1000 # Number of jobs to bulk queue at a time
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# Gets an estimated number of rows for a table
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def estimate_rows_in_table(table_name)
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exec_query('SELECT reltuples FROM pg_class WHERE relname = ' +
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"'#{table_name}'").to_a.first['reltuples']
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end
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# Adds `created_at` and `updated_at` columns with timezone information.
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#
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# This method is an improved version of Rails' built-in method `add_timestamps`.
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#
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# Available options are:
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# default - The default value for the column.
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# null - When set to `true` the column will allow NULL values.
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# The default is to not allow NULL values.
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def add_timestamps_with_timezone(table_name, **options)
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options[:null] = false if options[:null].nil?
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[:created_at, :updated_at].each do |column_name|
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if options[:default] && transaction_open?
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raise '`add_timestamps_with_timezone` with default value cannot be run inside a transaction. ' \
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'You can disable transactions by calling `disable_ddl_transaction!` ' \
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'in the body of your migration class'
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end
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# If default value is presented, use `add_column_with_default` method instead.
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if options[:default]
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add_column_with_default(
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table_name,
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column_name,
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:datetime_with_timezone,
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default: options[:default],
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allow_null: options[:null]
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)
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else
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add_column(table_name, column_name, :datetime_with_timezone, options)
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end
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end
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end
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# Creates a new index, concurrently when supported
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#
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# On PostgreSQL this method creates an index concurrently, on MySQL this
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# creates a regular index.
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#
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# Example:
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#
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# add_concurrent_index :users, :some_column
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#
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# See Rails' `add_index` for more info on the available arguments.
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def add_concurrent_index(table_name, column_name, **options)
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if transaction_open?
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raise 'add_concurrent_index can not be run inside a transaction, ' \
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'you can disable transactions by calling disable_ddl_transaction! ' \
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'in the body of your migration class'
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end
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if MigrationHelpers.postgresql?
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options = options.merge({ algorithm: :concurrently })
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disable_statement_timeout
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end
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add_index(table_name, column_name, options)
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end
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# Removes an existed index, concurrently when supported
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#
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# On PostgreSQL this method removes an index concurrently.
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#
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# Example:
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#
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# remove_concurrent_index :users, :some_column
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#
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# See Rails' `remove_index` for more info on the available arguments.
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def remove_concurrent_index(table_name, column_name, **options)
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if transaction_open?
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raise 'remove_concurrent_index can not be run inside a transaction, ' \
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'you can disable transactions by calling disable_ddl_transaction! ' \
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'in the body of your migration class'
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end
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if supports_drop_index_concurrently?
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options = options.merge({ algorithm: :concurrently })
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disable_statement_timeout
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end
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remove_index(table_name, options.merge({ column: column_name }))
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end
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# Removes an existing index, concurrently when supported
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#
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# On PostgreSQL this method removes an index concurrently.
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#
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# Example:
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#
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# remove_concurrent_index :users, "index_X_by_Y"
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#
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# See Rails' `remove_index` for more info on the available arguments.
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def remove_concurrent_index_by_name(table_name, index_name, **options)
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if transaction_open?
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raise 'remove_concurrent_index_by_name can not be run inside a transaction, ' \
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'you can disable transactions by calling disable_ddl_transaction! ' \
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'in the body of your migration class'
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end
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if supports_drop_index_concurrently?
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options = options.merge({ algorithm: :concurrently })
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disable_statement_timeout
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end
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remove_index(table_name, options.merge({ name: index_name }))
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end
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# Only available on Postgresql >= 9.2
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def supports_drop_index_concurrently?
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return false unless MigrationHelpers.postgresql?
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version = select_one("SELECT current_setting('server_version_num') AS v")['v'].to_i
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version >= 90200
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end
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# Adds a foreign key with only minimal locking on the tables involved.
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#
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# This method only requires minimal locking when using PostgreSQL. When
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# using MySQL this method will use Rails' default `add_foreign_key`.
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#
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# source - The source table containing the foreign key.
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# target - The target table the key points to.
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# column - The name of the column to create the foreign key on.
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# on_delete - The action to perform when associated data is removed,
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# defaults to "CASCADE".
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def add_concurrent_foreign_key(source, target, column:, on_delete: :cascade, target_col: 'id')
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# Transactions would result in ALTER TABLE locks being held for the
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# duration of the transaction, defeating the purpose of this method.
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if transaction_open?
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raise 'add_concurrent_foreign_key can not be run inside a transaction'
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end
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# While MySQL does allow disabling of foreign keys it has no equivalent
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# of PostgreSQL's "VALIDATE CONSTRAINT". As a result we'll just fall
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# back to the normal foreign key procedure.
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if MigrationHelpers.mysql?
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return add_foreign_key(source, target,
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column: column,
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on_delete: on_delete)
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else
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on_delete = 'SET NULL' if on_delete == :nullify
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end
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disable_statement_timeout
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key_name = concurrent_foreign_key_name(source, column, target_col)
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# Using NOT VALID allows us to create a key without immediately
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# validating it. This means we keep the ALTER TABLE lock only for a
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# short period of time. The key _is_ enforced for any newly created
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# data.
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execute <<-EOF.strip_heredoc
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ALTER TABLE #{source}
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ADD CONSTRAINT #{key_name}
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FOREIGN KEY (#{column})
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REFERENCES #{target} (#{target_col})
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#{on_delete ? "ON DELETE #{on_delete.upcase}" : ''}
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NOT VALID;
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EOF
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# Validate the existing constraint. This can potentially take a very
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# long time to complete, but fortunately does not lock the source table
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# while running.
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execute("ALTER TABLE #{source} VALIDATE CONSTRAINT #{key_name};")
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end
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# Returns the name for a concurrent foreign key.
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#
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# PostgreSQL constraint names have a limit of 63 bytes. The logic used
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# here is based on Rails' foreign_key_name() method, which unfortunately
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# is private so we can't rely on it directly.
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def concurrent_foreign_key_name(table, column, target_col)
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"fk_#{Digest::SHA256.hexdigest("#{table}_#{column}_#{target_col}_fk").first(10)}"
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end
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# Long-running migrations may take more than the timeout allowed by
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# the database. Disable the session's statement timeout to ensure
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# migrations don't get killed prematurely. (PostgreSQL only)
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def disable_statement_timeout
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execute('SET statement_timeout TO 0') if MigrationHelpers.postgresql?
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end
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# Updates the value of a column in batches.
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#
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# This method updates the table in batches of 5% of the total row count.
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# This method will continue updating rows until no rows remain.
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#
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# When given a block this method will yield two values to the block:
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#
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# 1. An instance of `Arel::Table` for the table that is being updated.
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# 2. The query to run as an Arel object.
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#
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# By supplying a block one can add extra conditions to the queries being
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# executed. Note that the same block is used for _all_ queries.
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#
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# Example:
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#
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# update_column_in_batches(:projects, :foo, 10) do |table, query|
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# query.where(table[:some_column].eq('hello'))
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# end
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#
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# This would result in this method updating only rows where
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# `projects.some_column` equals "hello".
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#
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# table - The name of the table.
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# column - The name of the column to update.
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# value - The value for the column.
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#
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# Rubocop's Metrics/AbcSize metric is disabled for this method as Rubocop
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# determines this method to be too complex while there's no way to make it
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# less "complex" without introducing extra methods (which actually will
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# make things _more_ complex).
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#
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# rubocop: disable Metrics/AbcSize
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def update_column_in_batches(table_name, column, value)
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if transaction_open?
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raise 'update_column_in_batches can not be run inside a transaction, ' \
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'you can disable transactions by calling disable_ddl_transaction! ' \
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'in the body of your migration class'
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end
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table = Arel::Table.new(table_name)
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total = estimate_rows_in_table(table_name).to_i
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if total == 0
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count_arel = table.project(Arel.star.count.as('count'))
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count_arel = yield table, count_arel if block_given?
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total = exec_query(count_arel.to_sql).to_hash.first['count'].to_i
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return if total == 0
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end
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# Update in batches of 5% until we run out of any rows to update.
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batch_size = ((total / 100.0) * 5.0).ceil
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max_size = 1000
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# The upper limit is 1000 to ensure we don't lock too many rows. For
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# example, for "merge_requests" even 1% of the table is around 35 000
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# rows for GitLab.com.
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batch_size = max_size if batch_size > max_size
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start_arel = table.project(table[:id]).order(table[:id].asc).take(1)
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start_arel = yield table, start_arel if block_given?
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first_row = exec_query(start_arel.to_sql).to_hash.first
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# In case there are no rows but we didn't catch it in the estimated size:
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return unless first_row
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start_id = first_row['id'].to_i
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say "Migrating #{table_name}.#{column} (~#{total.to_i} rows)"
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started_time = Time.zone.now
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last_time = Time.zone.now
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migrated = 0
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loop do
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stop_row = nil
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suppress_messages do
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stop_arel = table.project(table[:id])
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.where(table[:id].gteq(start_id))
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.order(table[:id].asc)
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.take(1)
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.skip(batch_size)
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stop_arel = yield table, stop_arel if block_given?
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stop_row = exec_query(stop_arel.to_sql).to_hash.first
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update_arel = Arel::UpdateManager.new
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.table(table)
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.set([[table[column], value]])
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.where(table[:id].gteq(start_id))
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if stop_row
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stop_id = stop_row['id'].to_i
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start_id = stop_id
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update_arel = update_arel.where(table[:id].lt(stop_id))
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end
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update_arel = yield table, update_arel if block_given?
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execute(update_arel.to_sql)
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end
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migrated += batch_size
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if Time.zone.now - last_time > 1
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status = "Migrated #{migrated} rows"
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percentage = 100.0 * migrated / total
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status += " (~#{sprintf('%.2f', percentage)}%, "
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remaining_time = (100.0 - percentage) * (Time.zone.now - started_time) / percentage
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status += "#{(remaining_time / 60).to_i}:"
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status += sprintf('%02d', remaining_time.to_i % 60)
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status += ' remaining, '
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# Tell users not to interrupt if we're almost done.
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if remaining_time > 10
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status += 'safe to interrupt'
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else
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status += 'DO NOT interrupt'
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end
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status += ')'
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say status, true
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last_time = Time.zone.now
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end
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# There are no more rows left to update.
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break unless stop_row
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end
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end
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# Adds a column with a default value without locking an entire table.
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#
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# This method runs the following steps:
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#
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# 1. Add the column with a default value of NULL.
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# 2. Change the default value of the column to the specified value.
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# 3. Update all existing rows in batches.
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# 4. Set a `NOT NULL` constraint on the column if desired (the default).
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#
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# These steps ensure a column can be added to a large and commonly used
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# table without locking the entire table for the duration of the table
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# modification.
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#
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# table - The name of the table to update.
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# column - The name of the column to add.
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# type - The column type (e.g. `:integer`).
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# default - The default value for the column.
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# limit - Sets a column limit. For example, for :integer, the default is
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# 4-bytes. Set `limit: 8` to allow 8-byte integers.
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# allow_null - When set to `true` the column will allow NULL values, the
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# default is to not allow NULL values.
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#
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# This method can also take a block which is passed directly to the
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# `update_column_in_batches` method.
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def add_column_with_default(table, column, type, default:, limit: nil, allow_null: false, &block)
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if transaction_open?
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raise 'add_column_with_default can not be run inside a transaction, ' \
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'you can disable transactions by calling disable_ddl_transaction! ' \
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'in the body of your migration class'
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end
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disable_statement_timeout
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transaction do
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if limit
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add_column(table, column, type, default: nil, limit: limit)
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else
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add_column(table, column, type, default: nil)
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end
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# Changing the default before the update ensures any newly inserted
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# rows already use the proper default value.
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change_column_default(table, column, default)
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end
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begin
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update_column_in_batches(table, column, default, &block)
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change_column_null(table, column, false) unless allow_null
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# We want to rescue _all_ exceptions here, even those that don't inherit
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# from StandardError.
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rescue Exception => error # rubocop: disable all
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remove_column(table, column)
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raise error
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end
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end
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# Renames a column without requiring downtime.
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#
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# Concurrent renames work by using database triggers to ensure both the
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# old and new column are in sync. However, this method will _not_ remove
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# the triggers or the old column automatically; this needs to be done
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# manually in a post-deployment migration. This can be done using the
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# method `cleanup_concurrent_column_rename`.
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#
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# table - The name of the database table containing the column.
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# old - The old column name.
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# new - The new column name.
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# type - The type of the new column. If no type is given the old column's
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# type is used.
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def rename_column_concurrently(table, old, new, type: nil)
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if transaction_open?
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raise 'rename_column_concurrently can not be run inside a transaction'
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end
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check_trigger_permissions!(table)
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trigger_name = rename_trigger_name(table, old, new)
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# If we were in the middle of update_column_in_batches, we should remove
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# the old column and start over, as we have no idea where we were.
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if column_for(table, new)
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if MigrationHelpers.postgresql?
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remove_rename_triggers_for_postgresql(table, trigger_name)
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else
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remove_rename_triggers_for_mysql(trigger_name)
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end
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remove_column(table, new)
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end
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old_col = column_for(table, old)
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new_type = type || old_col.type
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|
|
col_opts = {
|
|
precision: old_col.precision,
|
|
scale: old_col.scale,
|
|
}
|
|
|
|
# We may be trying to reset the limit on an integer column type, so let
|
|
# Rails handle that.
|
|
unless [:bigint, :integer].include?(new_type)
|
|
col_opts[:limit] = old_col.limit
|
|
end
|
|
|
|
add_column(table, new, new_type, col_opts)
|
|
|
|
# We set the default value _after_ adding the column so we don't end up
|
|
# updating any existing data with the default value. This isn't
|
|
# necessary since we copy over old values further down.
|
|
change_column_default(table, new, old_col.default) if old_col.default
|
|
|
|
quoted_table = quote_table_name(table)
|
|
quoted_old = quote_column_name(old)
|
|
quoted_new = quote_column_name(new)
|
|
|
|
if MigrationHelpers.postgresql?
|
|
install_rename_triggers_for_postgresql(trigger_name, quoted_table,
|
|
quoted_old, quoted_new)
|
|
else
|
|
install_rename_triggers_for_mysql(trigger_name, quoted_table,
|
|
quoted_old, quoted_new)
|
|
end
|
|
|
|
update_column_in_batches(table, new, Arel::Table.new(table)[old])
|
|
|
|
change_column_null(table, new, false) unless old_col.null
|
|
|
|
copy_indexes(table, old, new)
|
|
copy_foreign_keys(table, old, new)
|
|
end
|
|
|
|
# Changes the type of a column concurrently.
|
|
#
|
|
# table - The table containing the column.
|
|
# column - The name of the column to change.
|
|
# new_type - The new column type.
|
|
def change_column_type_concurrently(table, column, new_type)
|
|
temp_column = rename_column_name(column)
|
|
|
|
rename_column_concurrently(table, column, temp_column, type: new_type)
|
|
|
|
# Primary keys don't necessarily have an associated index.
|
|
if ActiveRecord::Base.get_primary_key(table) == column.to_s
|
|
old_pk_index_name = "index_#{table}_on_#{column}"
|
|
new_pk_index_name = "index_#{table}_on_#{column}_cm"
|
|
|
|
unless indexes_for(table, column).find{|i| i.name == old_pk_index_name}
|
|
add_concurrent_index(table, [temp_column], {
|
|
unique: true,
|
|
name: new_pk_index_name
|
|
})
|
|
end
|
|
end
|
|
end
|
|
|
|
# Performs cleanup of a concurrent type change.
|
|
#
|
|
# table - The table containing the column.
|
|
# column - The name of the column to change.
|
|
# new_type - The new column type.
|
|
def cleanup_concurrent_column_type_change(table, column)
|
|
temp_column = rename_column_name(column)
|
|
|
|
# Wait for the indices to be built
|
|
indexes_for(table, column).each do |index|
|
|
expected_name = index.name + '_cm'
|
|
|
|
puts "Waiting for index #{expected_name}"
|
|
sleep 1 until indexes_for(table, temp_column).find {|i| i.name == expected_name }
|
|
end
|
|
|
|
was_primary = (ActiveRecord::Base.get_primary_key(table) == column.to_s)
|
|
old_default_fn = column_for(table, column).default_function
|
|
|
|
old_fks = []
|
|
if was_primary
|
|
# Get any foreign keys pointing at this column we need to recreate, and
|
|
# remove the old ones.
|
|
# Based on code from:
|
|
# http://errorbank.blogspot.com/2011/03/list-all-foreign-keys-references-for.html
|
|
old_fks_res = execute <<-EOF.strip_heredoc
|
|
select m.relname as src_table,
|
|
(select a.attname
|
|
from pg_attribute a
|
|
where a.attrelid = m.oid
|
|
and a.attnum = o.conkey[1]
|
|
and a.attisdropped = false) as src_col,
|
|
o.conname as name,
|
|
o.confdeltype as on_delete
|
|
from pg_constraint o
|
|
left join pg_class f on f.oid = o.confrelid
|
|
left join pg_class c on c.oid = o.conrelid
|
|
left join pg_class m on m.oid = o.conrelid
|
|
where o.contype = 'f'
|
|
and o.conrelid in (
|
|
select oid from pg_class c where c.relkind = 'r')
|
|
and f.relname = '#{table}';
|
|
EOF
|
|
old_fks = old_fks_res.to_a
|
|
old_fks.each do |old_fk|
|
|
add_concurrent_foreign_key(
|
|
old_fk['src_table'],
|
|
table,
|
|
column: old_fk['src_col'],
|
|
target_col: temp_column,
|
|
on_delete: extract_foreign_key_action(old_fk['on_delete'])
|
|
)
|
|
|
|
remove_foreign_key(old_fk['src_table'], name: old_fk['name'])
|
|
end
|
|
end
|
|
|
|
# If there was a sequence owned by the old column, make it owned by the
|
|
# new column, as it will otherwise be deleted when we get rid of the
|
|
# old column.
|
|
if (seq_match = /^nextval\('([^']*)'(::text|::regclass)?\)/.match(old_default_fn))
|
|
seq_name = seq_match[1]
|
|
execute("ALTER SEQUENCE #{seq_name} OWNED BY #{table}.#{temp_column}")
|
|
end
|
|
|
|
transaction do
|
|
# This has to be performed in a transaction as otherwise we might have
|
|
# inconsistent data.
|
|
|
|
cleanup_concurrent_column_rename(table, column, temp_column)
|
|
rename_column(table, temp_column, column)
|
|
|
|
# If there was an old default function, we didn't copy it. Do that now
|
|
# in the transaction, so we don't miss anything.
|
|
change_column_default(table, column, -> { old_default_fn }) if old_default_fn
|
|
end
|
|
|
|
# Rename any indices back to what they should be.
|
|
indexes_for(table, column).each do |index|
|
|
next unless index.name.end_with?('_cm')
|
|
|
|
real_index_name = index.name.sub(/_cm$/, '')
|
|
rename_index(table, index.name, real_index_name)
|
|
end
|
|
|
|
# Rename any foreign keys back to names based on the real column.
|
|
foreign_keys_for(table, column).each do |fk|
|
|
old_fk_name = concurrent_foreign_key_name(fk.from_table, temp_column, 'id')
|
|
new_fk_name = concurrent_foreign_key_name(fk.from_table, column, 'id')
|
|
execute("ALTER TABLE #{fk.from_table} RENAME CONSTRAINT " +
|
|
"#{old_fk_name} TO #{new_fk_name}")
|
|
end
|
|
|
|
# Rename any foreign keys from other tables to names based on the real
|
|
# column.
|
|
old_fks.each do |old_fk|
|
|
old_fk_name = concurrent_foreign_key_name(old_fk['src_table'],
|
|
old_fk['src_col'], temp_column)
|
|
new_fk_name = concurrent_foreign_key_name(old_fk['src_table'],
|
|
old_fk['src_col'], column)
|
|
execute("ALTER TABLE #{old_fk['src_table']} RENAME CONSTRAINT " +
|
|
"#{old_fk_name} TO #{new_fk_name}")
|
|
end
|
|
|
|
# If the old column was a primary key, mark the new one as a primary key.
|
|
if was_primary
|
|
execute("ALTER TABLE #{table} ADD PRIMARY KEY USING INDEX " +
|
|
"index_#{table}_on_#{column}")
|
|
end
|
|
end
|
|
|
|
# Cleans up a concurrent column name.
|
|
#
|
|
# This method takes care of removing previously installed triggers as well
|
|
# as removing the old column.
|
|
#
|
|
# table - The name of the database table.
|
|
# old - The name of the old column.
|
|
# new - The name of the new column.
|
|
def cleanup_concurrent_column_rename(table, old, new)
|
|
trigger_name = rename_trigger_name(table, old, new)
|
|
|
|
check_trigger_permissions!(table)
|
|
|
|
if MigrationHelpers.postgresql?
|
|
remove_rename_triggers_for_postgresql(table, trigger_name)
|
|
else
|
|
remove_rename_triggers_for_mysql(trigger_name)
|
|
end
|
|
|
|
remove_column(table, old)
|
|
end
|
|
|
|
# Performs a concurrent column rename when using PostgreSQL.
|
|
def install_rename_triggers_for_postgresql(trigger, table, old, new)
|
|
execute <<-EOF.strip_heredoc
|
|
CREATE OR REPLACE FUNCTION #{trigger}()
|
|
RETURNS trigger AS
|
|
$BODY$
|
|
BEGIN
|
|
NEW.#{new} := NEW.#{old};
|
|
RETURN NEW;
|
|
END;
|
|
$BODY$
|
|
LANGUAGE 'plpgsql'
|
|
VOLATILE
|
|
EOF
|
|
|
|
execute <<-EOF.strip_heredoc
|
|
CREATE TRIGGER #{trigger}
|
|
BEFORE INSERT OR UPDATE
|
|
ON #{table}
|
|
FOR EACH ROW
|
|
EXECUTE PROCEDURE #{trigger}()
|
|
EOF
|
|
end
|
|
|
|
# Installs the triggers necessary to perform a concurrent column rename on
|
|
# MySQL.
|
|
def install_rename_triggers_for_mysql(trigger, table, old, new)
|
|
execute <<-EOF.strip_heredoc
|
|
CREATE TRIGGER #{trigger}_insert
|
|
BEFORE INSERT
|
|
ON #{table}
|
|
FOR EACH ROW
|
|
SET NEW.#{new} = NEW.#{old}
|
|
EOF
|
|
|
|
execute <<-EOF.strip_heredoc
|
|
CREATE TRIGGER #{trigger}_update
|
|
BEFORE UPDATE
|
|
ON #{table}
|
|
FOR EACH ROW
|
|
SET NEW.#{new} = NEW.#{old}
|
|
EOF
|
|
end
|
|
|
|
# Removes the triggers used for renaming a PostgreSQL column concurrently.
|
|
def remove_rename_triggers_for_postgresql(table, trigger)
|
|
execute("DROP TRIGGER IF EXISTS #{trigger} ON #{table}")
|
|
execute("DROP FUNCTION IF EXISTS #{trigger}()")
|
|
end
|
|
|
|
# Removes the triggers used for renaming a MySQL column concurrently.
|
|
def remove_rename_triggers_for_mysql(trigger)
|
|
execute("DROP TRIGGER IF EXISTS #{trigger}_insert")
|
|
execute("DROP TRIGGER IF EXISTS #{trigger}_update")
|
|
end
|
|
|
|
# Returns the (base) name to use for triggers when renaming columns.
|
|
def rename_trigger_name(table, old, new)
|
|
'trigger_' + Digest::SHA256.hexdigest("#{table}_#{old}_#{new}").first(12)
|
|
end
|
|
|
|
# Returns the name to use for temporary rename columns.
|
|
def rename_column_name(base)
|
|
base.to_s + '_cm'
|
|
end
|
|
|
|
# Returns an Array containing the indexes for the given column
|
|
def indexes_for(table, column)
|
|
column = column.to_s
|
|
|
|
indexes(table).select { |index| index.columns.include?(column) }
|
|
end
|
|
|
|
# Returns an Array containing the foreign keys for the given column.
|
|
def foreign_keys_for(table, column)
|
|
column = column.to_s
|
|
|
|
foreign_keys(table).select { |fk| fk.column == column }
|
|
end
|
|
|
|
# Copies all indexes for the old column to a new column.
|
|
#
|
|
# table - The table containing the columns and indexes.
|
|
# old - The old column.
|
|
# new - The new column.
|
|
def copy_indexes(table, old, new)
|
|
old = old.to_s
|
|
new = new.to_s
|
|
|
|
indexes_for(table, old).each do |index|
|
|
new_columns = index.columns.map do |column|
|
|
column == old ? new : column
|
|
end
|
|
|
|
# This is necessary as we can't properly rename indexes such as
|
|
# "ci_taggings_idx".
|
|
name = index.name + '_cm'
|
|
|
|
# If the order contained the old column, map it to the new one.
|
|
order = index.orders
|
|
if order.key?(old)
|
|
order[new] = order.delete(old)
|
|
end
|
|
|
|
options = {
|
|
unique: index.unique,
|
|
name: name,
|
|
length: index.lengths,
|
|
order: order
|
|
}
|
|
|
|
# These options are not supported by MySQL, so we only add them if
|
|
# they were previously set.
|
|
options[:using] = index.using if index.using
|
|
options[:where] = index.where if index.where
|
|
|
|
add_concurrent_index(table, new_columns, options)
|
|
end
|
|
end
|
|
|
|
# Copies all foreign keys for the old column to the new column.
|
|
#
|
|
# table - The table containing the columns and indexes.
|
|
# old - The old column.
|
|
# new - The new column.
|
|
def copy_foreign_keys(table, old, new)
|
|
foreign_keys_for(table, old).each do |fk|
|
|
add_concurrent_foreign_key(fk.from_table,
|
|
fk.to_table,
|
|
column: new,
|
|
on_delete: fk.on_delete)
|
|
end
|
|
end
|
|
|
|
# Returns the column for the given table and column name.
|
|
def column_for(table, name)
|
|
name = name.to_s
|
|
|
|
columns(table).find { |column| column.name == name }
|
|
end
|
|
|
|
# This will replace the first occurrence of a string in a column with
|
|
# the replacement
|
|
# On postgresql we can use `regexp_replace` for that.
|
|
# On mysql we find the location of the pattern, and overwrite it
|
|
# with the replacement
|
|
def replace_sql(column, pattern, replacement)
|
|
quoted_pattern = Arel::Nodes::Quoted.new(pattern.to_s)
|
|
quoted_replacement = Arel::Nodes::Quoted.new(replacement.to_s)
|
|
|
|
if MigrationHelpers.mysql?
|
|
locate = Arel::Nodes::NamedFunction
|
|
.new('locate', [quoted_pattern, column])
|
|
insert_in_place = Arel::Nodes::NamedFunction
|
|
.new('insert', [column, locate, pattern.size, quoted_replacement])
|
|
|
|
Arel::Nodes::SqlLiteral.new(insert_in_place.to_sql)
|
|
else
|
|
replace = Arel::Nodes::NamedFunction
|
|
.new("regexp_replace", [column, quoted_pattern, quoted_replacement])
|
|
Arel::Nodes::SqlLiteral.new(replace.to_sql)
|
|
end
|
|
end
|
|
|
|
def remove_foreign_key_without_error(*args)
|
|
remove_foreign_key(*args)
|
|
rescue ArgumentError
|
|
end
|
|
|
|
def sidekiq_queue_migrate(queue_from, to:)
|
|
while sidekiq_queue_length(queue_from) > 0
|
|
Sidekiq.redis do |conn|
|
|
conn.rpoplpush "queue:#{queue_from}", "queue:#{to}"
|
|
end
|
|
end
|
|
end
|
|
|
|
def sidekiq_queue_length(queue_name)
|
|
Sidekiq.redis do |conn|
|
|
conn.llen("queue:#{queue_name}")
|
|
end
|
|
end
|
|
|
|
def check_trigger_permissions!(table)
|
|
unless Grant.create_and_execute_trigger?(table)
|
|
dbname = ActiveRecord::Base.configurations[Rails.env]['database']
|
|
user = ActiveRecord::Base.configurations[Rails.env]['username'] || ENV['USER']
|
|
|
|
raise <<-EOF
|
|
Your database user is not allowed to create, drop, or execute triggers on the
|
|
table #{table}.
|
|
|
|
If you are using PostgreSQL you can solve this by logging in to the Mastodon
|
|
database (#{dbname}) using a super user and running:
|
|
|
|
ALTER USER #{user} WITH SUPERUSER
|
|
|
|
The query will grant the user super user permissions, ensuring you don't run
|
|
into similar problems in the future (e.g. when new tables are created).
|
|
EOF
|
|
end
|
|
end
|
|
|
|
# Bulk queues background migration jobs for an entire table, batched by ID range.
|
|
# "Bulk" meaning many jobs will be pushed at a time for efficiency.
|
|
# If you need a delay interval per job, then use `queue_background_migration_jobs_by_range_at_intervals`.
|
|
#
|
|
# model_class - The table being iterated over
|
|
# job_class_name - The background migration job class as a string
|
|
# batch_size - The maximum number of rows per job
|
|
#
|
|
# Example:
|
|
#
|
|
# class Route < ActiveRecord::Base
|
|
# include EachBatch
|
|
# self.table_name = 'routes'
|
|
# end
|
|
#
|
|
# bulk_queue_background_migration_jobs_by_range(Route, 'ProcessRoutes')
|
|
#
|
|
# Where the model_class includes EachBatch, and the background migration exists:
|
|
#
|
|
# class Gitlab::BackgroundMigration::ProcessRoutes
|
|
# def perform(start_id, end_id)
|
|
# # do something
|
|
# end
|
|
# end
|
|
def bulk_queue_background_migration_jobs_by_range(model_class, job_class_name, batch_size: BACKGROUND_MIGRATION_BATCH_SIZE)
|
|
raise "#{model_class} does not have an ID to use for batch ranges" unless model_class.column_names.include?('id')
|
|
|
|
jobs = []
|
|
|
|
model_class.each_batch(of: batch_size) do |relation|
|
|
start_id, end_id = relation.pluck('MIN(id), MAX(id)').first
|
|
|
|
if jobs.length >= BACKGROUND_MIGRATION_JOB_BUFFER_SIZE
|
|
# Note: This code path generally only helps with many millions of rows
|
|
# We push multiple jobs at a time to reduce the time spent in
|
|
# Sidekiq/Redis operations. We're using this buffer based approach so we
|
|
# don't need to run additional queries for every range.
|
|
BackgroundMigrationWorker.perform_bulk(jobs)
|
|
jobs.clear
|
|
end
|
|
|
|
jobs << [job_class_name, [start_id, end_id]]
|
|
end
|
|
|
|
BackgroundMigrationWorker.perform_bulk(jobs) unless jobs.empty?
|
|
end
|
|
|
|
# Queues background migration jobs for an entire table, batched by ID range.
|
|
# Each job is scheduled with a `delay_interval` in between.
|
|
# If you use a small interval, then some jobs may run at the same time.
|
|
#
|
|
# model_class - The table being iterated over
|
|
# job_class_name - The background migration job class as a string
|
|
# delay_interval - The duration between each job's scheduled time (must respond to `to_f`)
|
|
# batch_size - The maximum number of rows per job
|
|
#
|
|
# Example:
|
|
#
|
|
# class Route < ActiveRecord::Base
|
|
# include EachBatch
|
|
# self.table_name = 'routes'
|
|
# end
|
|
#
|
|
# queue_background_migration_jobs_by_range_at_intervals(Route, 'ProcessRoutes', 1.minute)
|
|
#
|
|
# Where the model_class includes EachBatch, and the background migration exists:
|
|
#
|
|
# class Gitlab::BackgroundMigration::ProcessRoutes
|
|
# def perform(start_id, end_id)
|
|
# # do something
|
|
# end
|
|
# end
|
|
def queue_background_migration_jobs_by_range_at_intervals(model_class, job_class_name, delay_interval, batch_size: BACKGROUND_MIGRATION_BATCH_SIZE)
|
|
raise "#{model_class} does not have an ID to use for batch ranges" unless model_class.column_names.include?('id')
|
|
|
|
model_class.each_batch(of: batch_size) do |relation, index|
|
|
start_id, end_id = relation.pluck('MIN(id), MAX(id)').first
|
|
|
|
# `BackgroundMigrationWorker.bulk_perform_in` schedules all jobs for
|
|
# the same time, which is not helpful in most cases where we wish to
|
|
# spread the work over time.
|
|
BackgroundMigrationWorker.perform_in(delay_interval * index, job_class_name, [start_id, end_id])
|
|
end
|
|
end
|
|
|
|
private
|
|
|
|
# https://github.com/rails/rails/blob/v5.2.0/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb#L678-L684
|
|
def extract_foreign_key_action(specifier)
|
|
case specifier
|
|
when 'c'; :cascade
|
|
when 'n'; :nullify
|
|
when 'r'; :restrict
|
|
end
|
|
end
|
|
end
|
|
end
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# rubocop:enable all
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