127 lines
4.6 KiB
Ruby
127 lines
4.6 KiB
Ruby
# frozen_string_literal: true
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module Gitlab
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module Database
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module Reindexing
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# This is a >= PG12 reindexing strategy based on `REINDEX CONCURRENTLY`
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class ReindexConcurrently
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ReindexError = Class.new(StandardError)
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TEMPORARY_INDEX_PATTERN = '\_ccnew[0-9]*'
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STATEMENT_TIMEOUT = 24.hours
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PG_MAX_INDEX_NAME_LENGTH = 63
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attr_reader :index, :logger
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def initialize(index, logger: Gitlab::AppLogger)
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@index = index
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@logger = logger
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end
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def perform
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raise ReindexError, 'indexes serving an exclusion constraint are currently not supported' if index.exclusion?
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raise ReindexError, 'index is a left-over temporary index from a previous reindexing run' if index.name =~ /#{TEMPORARY_INDEX_PATTERN}/o
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# Expression indexes require additional statistics in `pg_statistic`:
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# select * from pg_statistic where starelid = (select oid from pg_class where relname = 'some_index');
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#
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# In PG12, this has been fixed in https://gitlab.com/postgres/postgres/-/commit/b17ff07aa3eb142d2cde2ea00e4a4e8f63686f96.
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# Discussion happened in https://www.postgresql.org/message-id/flat/CAFcNs%2BqpFPmiHd1oTXvcPdvAHicJDA9qBUSujgAhUMJyUMb%2BSA%40mail.gmail.com
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# following a GitLab.com incident that surfaced this (https://gitlab.com/gitlab-com/gl-infra/production/-/issues/2885).
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#
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# While this has been backpatched, we continue to disable expression indexes until further review.
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raise ReindexError, 'expression indexes are currently not supported' if index.expression?
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begin
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with_logging do
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set_statement_timeout do
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execute("REINDEX INDEX CONCURRENTLY #{quote_table_name(index.schema)}.#{quote_table_name(index.name)}")
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end
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end
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ensure
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cleanup_dangling_indexes
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end
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end
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private
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def with_logging
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bloat_size = index.bloat_size
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ondisk_size_before = index.ondisk_size_bytes
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logger.info(
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message: "Starting reindex of #{index}",
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index: index.identifier,
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table: index.tablename,
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estimated_bloat_bytes: bloat_size,
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index_size_before_bytes: ondisk_size_before,
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relative_bloat_level: index.relative_bloat_level
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)
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duration = Benchmark.realtime do
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yield
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end
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index.reset
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logger.info(
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message: "Finished reindex of #{index}",
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index: index.identifier,
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table: index.tablename,
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estimated_bloat_bytes: bloat_size,
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index_size_before_bytes: ondisk_size_before,
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index_size_after_bytes: index.ondisk_size_bytes,
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relative_bloat_level: index.relative_bloat_level,
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duration_s: duration.round(2)
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)
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end
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def cleanup_dangling_indexes
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Gitlab::Database::PostgresIndex.match("#{TEMPORARY_INDEX_PATTERN}$").each do |lingering_index|
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# Example lingering index name: some_index_ccnew1
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# Example prefix: 'some_index'
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prefix = lingering_index.name.gsub(/#{TEMPORARY_INDEX_PATTERN}/o, '')
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# Example suffix: '_ccnew1'
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suffix = lingering_index.name.match(/#{TEMPORARY_INDEX_PATTERN}/o)[0]
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# Only remove if the lingering index name could have been chosen
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# as a result of a REINDEX operation (considering that PostgreSQL
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# truncates index names to 63 chars and adds a suffix).
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if index.name[0...PG_MAX_INDEX_NAME_LENGTH - suffix.length] == prefix
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remove_index(lingering_index)
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end
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end
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end
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def remove_index(index)
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logger.info("Removing dangling index #{index.identifier}")
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retries = Gitlab::Database::WithLockRetriesOutsideTransaction.new(
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connection: connection,
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timing_configuration: REMOVE_INDEX_RETRY_CONFIG,
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klass: self.class,
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logger: logger
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)
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retries.run(raise_on_exhaustion: false) do
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execute("DROP INDEX CONCURRENTLY IF EXISTS #{quote_table_name(index.schema)}.#{quote_table_name(index.name)}")
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end
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end
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def set_statement_timeout
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execute("SET statement_timeout TO '%ds'" % STATEMENT_TIMEOUT)
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yield
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ensure
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execute('RESET statement_timeout')
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end
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delegate :execute, :quote_table_name, to: :connection
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def connection
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@connection ||= index.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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