97 lines
4 KiB
Ruby
97 lines
4 KiB
Ruby
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# frozen_string_literal: true
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module Gitlab
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module Database
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class TablesTruncate
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GITLAB_SCHEMAS_TO_IGNORE = %i[gitlab_geo].freeze
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def initialize(database_name:, min_batch_size:, logger: nil, until_table: nil, dry_run: false)
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@database_name = database_name
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@min_batch_size = min_batch_size
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@logger = logger
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@until_table = until_table
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@dry_run = dry_run
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end
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def execute
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raise "Cannot truncate legacy tables in single-db setup" unless Gitlab::Database.has_config?(:ci)
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raise "database is not supported" unless %w[main ci].include?(database_name)
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logger&.info "DRY RUN:" if dry_run
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connection = Gitlab::Database.database_base_models[database_name].connection
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schemas_for_connection = Gitlab::Database.gitlab_schemas_for_connection(connection)
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tables_to_truncate = Gitlab::Database::GitlabSchema.tables_to_schema.reject do |_, schema_name|
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(GITLAB_SCHEMAS_TO_IGNORE.union(schemas_for_connection)).include?(schema_name)
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end.keys
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tables_sorted = Gitlab::Database::TablesSortedByForeignKeys.new(connection, tables_to_truncate).execute
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# Checking if all the tables have the write-lock triggers
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# to make sure we are deleting the right tables on the right database.
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tables_sorted.flatten.each do |table_name|
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query = <<~SQL
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SELECT COUNT(*) from information_schema.triggers
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WHERE event_object_table = '#{table_name}'
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AND trigger_name = 'gitlab_schema_write_trigger_for_#{table_name}'
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SQL
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if connection.select_value(query) == 0
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raise "Table '#{table_name}' is not locked for writes. Run the rake task gitlab:db:lock_writes first"
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end
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end
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if until_table
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table_index = tables_sorted.find_index { |tables_group| tables_group.include?(until_table) }
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raise "The table '#{until_table}' is not within the truncated tables" if table_index.nil?
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tables_sorted = tables_sorted[0..table_index]
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end
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# min_batch_size is the minimum number of new tables to truncate at each stage.
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# But in each stage we have also have to truncate the already truncated tables in the previous stages
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logger&.info "Truncating legacy tables for the database #{database_name}"
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truncate_tables_in_batches(connection, tables_sorted, min_batch_size)
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end
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private
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attr_accessor :database_name, :min_batch_size, :logger, :dry_run, :until_table
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def truncate_tables_in_batches(connection, tables_sorted, min_batch_size)
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truncated_tables = []
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tables_sorted.flatten.each do |table|
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sql_statement = "SELECT set_config('lock_writes.#{table}', 'false', false)"
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logger&.info(sql_statement)
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connection.execute(sql_statement) unless dry_run
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end
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# We do the truncation in stages to avoid high IO
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# In each stage, we truncate the new tables along with the already truncated
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# tables before. That's because PostgreSQL doesn't allow to truncate any table (A)
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# without truncating any other table (B) that has a Foreign Key pointing to the table (A).
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# even if table (B) is empty, because it has been already truncated in a previous stage.
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tables_sorted.in_groups_of(min_batch_size, false).each do |tables_groups|
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new_tables_to_truncate = tables_groups.flatten
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logger&.info "= New tables to truncate: #{new_tables_to_truncate.join(', ')}"
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truncated_tables.push(*new_tables_to_truncate).tap(&:sort!)
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sql_statements = [
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"SET LOCAL statement_timeout = 0",
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"SET LOCAL lock_timeout = 0",
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"TRUNCATE TABLE #{truncated_tables.join(', ')} RESTRICT"
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]
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sql_statements.each { |sql_statement| logger&.info(sql_statement) }
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next if dry_run
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connection.transaction do
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sql_statements.each { |sql_statement| connection.execute(sql_statement) }
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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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end
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