97 lines
3.2 KiB
Ruby
97 lines
3.2 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
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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)
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@model = model
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@partitioning_key = partitioning_key
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end
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def current_partitions
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result = connection.select_all(<<~SQL)
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select
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pg_class.relname,
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parent_class.relname as base_table,
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pg_get_expr(pg_class.relpartbound, inhrelid) as condition
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from pg_class
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inner join pg_inherits i on pg_class.oid = inhrelid
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inner join pg_class parent_class on parent_class.oid = inhparent
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inner join pg_namespace ON pg_namespace.oid = pg_class.relnamespace
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where pg_namespace.nspname = #{connection.quote(Gitlab::Database::DYNAMIC_PARTITIONS_SCHEMA)}
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and parent_class.relname = #{connection.quote(table_name)}
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and pg_class.relispartition
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order by pg_class.relname
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SQL
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result.map do |record|
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TimePartition.from_sql(table_name, record['relname'], record['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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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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parts << partition_for(upper_bound: min_date)
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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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# 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 connection
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ActiveRecord::Base.connection
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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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