39 lines
1.4 KiB
Ruby
39 lines
1.4 KiB
Ruby
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# frozen_string_literal: true
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module Gitlab
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module BackgroundMigration
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module BatchingStrategies
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# Generic batching class for use with a BatchedBackgroundMigration.
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# Batches over the given table and column combination, returning the MIN() and MAX()
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# values for the next batch as an array.
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#
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# If no more batches exist in the table, returns nil.
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class PrimaryKeyBatchingStrategy
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include Gitlab::Database::DynamicModelHelpers
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# Finds and returns the next batch in the table.
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#
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# table_name - The table to batch over
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# column_name - The column to batch over
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# batch_min_value - The minimum value which the next batch will start at
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# batch_size - The size of the next batch
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def next_batch(table_name, column_name, batch_min_value:, batch_size:)
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model_class = define_batchable_model(table_name)
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quoted_column_name = model_class.connection.quote_column_name(column_name)
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relation = model_class.where("#{quoted_column_name} >= ?", batch_min_value)
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next_batch_bounds = nil
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relation.each_batch(of: batch_size, column: column_name) do |batch| # rubocop:disable Lint/UnreachableLoop
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next_batch_bounds = batch.pluck(Arel.sql("MIN(#{quoted_column_name}), MAX(#{quoted_column_name})")).first
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break
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end
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next_batch_bounds
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end
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end
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end
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end
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end
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