116 lines
3.6 KiB
Ruby
116 lines
3.6 KiB
Ruby
# frozen_string_literal: true
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module Gitlab
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module BackgroundMigration
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# Base class for batched background migrations. Subclasses should implement the `#perform`
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# method as the entry point for the job's execution.
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#
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# Job arguments needed must be defined explicitly,
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# see https://docs.gitlab.com/ee/development/database/batched_background_migrations.html#job-arguments.
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class BatchedMigrationJob
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include Gitlab::Database::DynamicModelHelpers
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def initialize(
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start_id:, end_id:, batch_table:, batch_column:, sub_batch_size:, pause_ms:, job_arguments: [], connection:
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)
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@start_id = start_id
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@end_id = end_id
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@batch_table = batch_table
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@batch_column = batch_column
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@sub_batch_size = sub_batch_size
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@pause_ms = pause_ms
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@job_arguments = job_arguments
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@connection = connection
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end
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def self.generic_instance(batch_table:, batch_column:, job_arguments: [], connection:)
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new(
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batch_table: batch_table, batch_column: batch_column,
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job_arguments: job_arguments, connection: connection,
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start_id: 0, end_id: 0, sub_batch_size: 0, pause_ms: 0
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)
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end
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def self.job_arguments_count
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0
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end
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def self.job_arguments(*args)
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args.each.with_index do |arg, index|
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define_method(arg) do
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@job_arguments[index]
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end
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end
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define_singleton_method(:job_arguments_count) do
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args.count
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end
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end
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def self.scope_to(scope)
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define_method(:filter_batch) do |relation|
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instance_exec(relation, &scope)
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end
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end
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def filter_batch(relation)
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relation
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end
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def perform
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raise NotImplementedError, "subclasses of #{self.class.name} must implement #{__method__}"
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end
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def batch_metrics
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@batch_metrics ||= Gitlab::Database::BackgroundMigration::BatchMetrics.new
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end
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private
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attr_reader :start_id, :end_id, :batch_table, :batch_column, :sub_batch_size, :pause_ms, :connection
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def each_sub_batch(operation_name: :default, batching_arguments: {}, batching_scope: nil)
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all_batching_arguments = { column: batch_column, of: sub_batch_size }.merge(batching_arguments)
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relation = filter_batch(base_relation)
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sub_batch_relation = filter_sub_batch(relation, batching_scope)
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sub_batch_relation.each_batch(**all_batching_arguments) do |relation|
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batch_metrics.instrument_operation(operation_name) do
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yield relation
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end
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sleep([pause_ms, 0].max * 0.001)
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end
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end
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def distinct_each_batch(operation_name: :default, batching_arguments: {})
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if base_relation != filter_batch(base_relation)
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raise 'distinct_each_batch can not be used when additional filters are defined with scope_to'
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end
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all_batching_arguments = { column: batch_column, of: sub_batch_size }.merge(batching_arguments)
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base_relation.distinct_each_batch(**all_batching_arguments) do |relation|
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batch_metrics.instrument_operation(operation_name) do
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yield relation
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end
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sleep([pause_ms, 0].max * 0.001)
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end
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end
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def base_relation
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define_batchable_model(batch_table, connection: connection)
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.where(batch_column => start_id..end_id)
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end
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def filter_sub_batch(relation, batching_scope = nil)
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return relation unless batching_scope
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batching_scope.call(relation)
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end
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end
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end
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end
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