106 lines
3.4 KiB
Ruby
106 lines
3.4 KiB
Ruby
# frozen_string_literal: true
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module Gitlab
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module Database
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module Partitioning
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class MonthlyStrategy
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attr_reader :model, :partitioning_key, :retain_for, :retain_non_empty_partitions
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# We create this many partitions in the future
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HEADROOM = 6.months
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delegate :table_name, to: :model
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def initialize(model, partitioning_key, retain_for: nil, retain_non_empty_partitions: false)
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@model = model
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@partitioning_key = partitioning_key
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@retain_for = retain_for
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@retain_non_empty_partitions = retain_non_empty_partitions
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end
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def current_partitions
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Gitlab::Database::PostgresPartition.for_parent_table(table_name).map do |partition|
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TimePartition.from_sql(table_name, partition.name, partition.condition)
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end
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end
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# Check the currently existing partitions and determine which ones are missing
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def missing_partitions
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desired_partitions - current_partitions
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end
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def extra_partitions
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partitions = current_partitions - desired_partitions
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partitions.reject!(&:holds_data?) if retain_non_empty_partitions
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partitions
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end
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def after_adding_partitions
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# No-op, required by the partition manager
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end
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private
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def desired_partitions
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[].tap do |parts|
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min_date, max_date = relevant_range
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if pruning_old_partitions? && min_date <= oldest_active_date
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min_date = oldest_active_date.beginning_of_month
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else
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parts << partition_for(upper_bound: min_date)
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end
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while min_date < max_date
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next_date = min_date.next_month
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parts << partition_for(lower_bound: min_date, upper_bound: next_date)
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min_date = next_date
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end
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end
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end
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# This determines the relevant time range for which we expect to have data
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# (and therefore need to create partitions for).
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#
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# Note: We typically expect the first partition to be half-unbounded, i.e.
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# to start from MINVALUE to a specific date `x`. The range returned
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# does not include the range of the first, half-unbounded partition.
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def relevant_range
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if (first_partition = current_partitions.min)
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# Case 1: First partition starts with MINVALUE, i.e. from is nil -> start with first real partition
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# Case 2: Rather unexpectedly, first partition does not start with MINVALUE, i.e. from is not nil
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# In this case, use first partition beginning as a start
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min_date = first_partition.from || first_partition.to
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end
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if pruning_old_partitions?
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min_date ||= oldest_active_date
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end
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# In case we don't have a partition yet
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min_date ||= Date.today
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min_date = min_date.beginning_of_month
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max_date = Date.today.end_of_month + HEADROOM
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[min_date, max_date]
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end
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def partition_for(lower_bound: nil, upper_bound:)
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TimePartition.new(table_name, lower_bound, upper_bound)
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end
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def pruning_old_partitions?
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retain_for.present?
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end
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def oldest_active_date
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(Date.today - retain_for).beginning_of_month
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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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