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
|
# frozen_string_literal: true
module Gitlab
module BackgroundMigration
module BatchingStrategies
# Generic batching class for use with a BatchedBackgroundMigration.
# Batches over the given table and column combination, returning the MIN() and MAX()
# values for the next batch as an array.
#
# If no more batches exist in the table, returns nil.
class PrimaryKeyBatchingStrategy < BaseStrategy
include Gitlab::Database::DynamicModelHelpers
# Finds and returns the next batch in the table.
#
# table_name - The table to batch over
# column_name - The column to batch over
# batch_min_value - The minimum value which the next batch will start at
# batch_size - The size of the next batch
# job_arguments - The migration job arguments
# job_class - The migration job class
def next_batch(table_name, column_name, batch_min_value:, batch_size:, job_arguments:, job_class: nil)
model_class = define_batchable_model(table_name, connection: connection)
arel_column = model_class.arel_table[column_name]
relation = model_class.where(arel_column.gteq(batch_min_value))
if job_class
relation = filter_batch(relation,
table_name: table_name, column_name: column_name,
job_class: job_class, job_arguments: job_arguments
)
end
next_batch_bounds = nil
relation.each_batch(of: batch_size, column: column_name) do |batch| # rubocop:disable Lint/UnreachableLoop
next_batch_bounds = batch.pick(arel_column.minimum, arel_column.maximum)
break
end
next_batch_bounds
end
private
def filter_batch(relation, table_name:, column_name:, job_class:, job_arguments: [])
return relation unless job_class.respond_to?(:generic_instance)
job = job_class.generic_instance(
batch_table: table_name, batch_column: column_name,
job_arguments: job_arguments, connection: connection
)
job.filter_batch(relation)
end
end
end
end
end
|
