1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
|
# frozen_string_literal: true
module LooseForeignKeys
# rubocop: disable CodeReuse/ActiveRecord
class CleanerService
DELETE_LIMIT = 1000
UPDATE_LIMIT = 500
def initialize(loose_foreign_key_definition:, connection:, deleted_parent_records:, with_skip_locked: false)
@loose_foreign_key_definition = loose_foreign_key_definition
@connection = connection
@deleted_parent_records = deleted_parent_records
@with_skip_locked = with_skip_locked
end
def execute
result = connection.execute(build_query)
{ affected_rows: result.cmd_tuples, table: loose_foreign_key_definition.from_table }
end
def async_delete?
loose_foreign_key_definition.on_delete == :async_delete
end
def async_nullify?
loose_foreign_key_definition.on_delete == :async_nullify
end
private
attr_reader :loose_foreign_key_definition, :connection, :deleted_parent_records, :with_skip_locked
def build_query
query = if async_delete?
delete_query
elsif async_nullify?
update_query
else
raise "Invalid on_delete argument: #{loose_foreign_key_definition.on_delete}"
end
unless query.include?(%{"#{loose_foreign_key_definition.column}" IN (})
raise("FATAL: foreign key condition is missing from the generated query: #{query}")
end
query
end
def arel_table
@arel_table ||= Arel::Table.new(loose_foreign_key_definition.from_table)
end
def primary_keys
@primary_keys ||= connection.primary_keys(loose_foreign_key_definition.from_table).map { |key| arel_table[key] }
end
def quoted_table_name
@quoted_table_name ||= Arel.sql(connection.quote_table_name(loose_foreign_key_definition.from_table))
end
def delete_query
query = Arel::DeleteManager.new
query.from(quoted_table_name)
add_in_query_with_limit(query, DELETE_LIMIT)
end
def update_query
query = Arel::UpdateManager.new
query.table(quoted_table_name)
query.set([[arel_table[loose_foreign_key_definition.column], nil]])
add_in_query_with_limit(query, UPDATE_LIMIT)
end
# IN query with one or composite primary key
# WHERE (primary_key1, primary_key2) IN (subselect)
def add_in_query_with_limit(query, limit)
columns = Arel::Nodes::Grouping.new(primary_keys)
query.where(columns.in(in_query_with_limit(limit))).to_sql
end
# Builds the following sub-query
# SELECT primary_keys FROM table WHERE foreign_key IN (1, 2, 3) LIMIT N
def in_query_with_limit(limit)
in_query = Arel::SelectManager.new
in_query.from(quoted_table_name)
in_query.where(arel_table[loose_foreign_key_definition.column].in(deleted_parent_records.map(&:primary_key_value)))
in_query.projections = primary_keys
in_query.take(limit)
in_query.lock(Arel.sql('FOR UPDATE SKIP LOCKED')) if with_skip_locked
in_query
end
end
# rubocop: enable CodeReuse/ActiveRecord
end
|
