97 lines
3 KiB
Ruby
97 lines
3 KiB
Ruby
# frozen_string_literal: true
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module LooseForeignKeys
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# rubocop: disable CodeReuse/ActiveRecord
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class CleanerService
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DELETE_LIMIT = 1000
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UPDATE_LIMIT = 500
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def initialize(loose_foreign_key_definition:, connection:, deleted_parent_records:, with_skip_locked: false)
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@loose_foreign_key_definition = loose_foreign_key_definition
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@connection = connection
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@deleted_parent_records = deleted_parent_records
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@with_skip_locked = with_skip_locked
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end
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def execute
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result = connection.execute(build_query)
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{ affected_rows: result.cmd_tuples, table: loose_foreign_key_definition.from_table }
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end
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def async_delete?
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loose_foreign_key_definition.on_delete == :async_delete
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end
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def async_nullify?
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loose_foreign_key_definition.on_delete == :async_nullify
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end
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private
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attr_reader :loose_foreign_key_definition, :connection, :deleted_parent_records, :with_skip_locked
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def build_query
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query = if async_delete?
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delete_query
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elsif async_nullify?
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update_query
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else
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raise "Invalid on_delete argument: #{loose_foreign_key_definition.on_delete}"
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end
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unless query.include?(%{"#{loose_foreign_key_definition.column}" IN (})
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raise("FATAL: foreign key condition is missing from the generated query: #{query}")
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end
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query
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end
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def arel_table
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@arel_table ||= Arel::Table.new(loose_foreign_key_definition.from_table)
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end
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def primary_keys
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@primary_keys ||= connection.primary_keys(loose_foreign_key_definition.from_table).map { |key| arel_table[key] }
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end
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def quoted_table_name
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@quoted_table_name ||= Arel.sql(connection.quote_table_name(loose_foreign_key_definition.from_table))
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end
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def delete_query
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query = Arel::DeleteManager.new
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query.from(quoted_table_name)
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add_in_query_with_limit(query, DELETE_LIMIT)
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end
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def update_query
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query = Arel::UpdateManager.new
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query.table(quoted_table_name)
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query.set([[arel_table[loose_foreign_key_definition.column], nil]])
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add_in_query_with_limit(query, UPDATE_LIMIT)
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end
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# IN query with one or composite primary key
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# WHERE (primary_key1, primary_key2) IN (subselect)
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def add_in_query_with_limit(query, limit)
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columns = Arel::Nodes::Grouping.new(primary_keys)
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query.where(columns.in(in_query_with_limit(limit))).to_sql
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end
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# Builds the following sub-query
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# SELECT primary_keys FROM table WHERE foreign_key IN (1, 2, 3) LIMIT N
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def in_query_with_limit(limit)
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in_query = Arel::SelectManager.new
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in_query.from(quoted_table_name)
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in_query.where(arel_table[loose_foreign_key_definition.column].in(deleted_parent_records.map(&:primary_key_value)))
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in_query.projections = primary_keys
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in_query.take(limit)
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in_query.lock(Arel.sql('FOR UPDATE SKIP LOCKED')) if with_skip_locked
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in_query
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end
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end
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# rubocop: enable CodeReuse/ActiveRecord
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end
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