81 lines
1.9 KiB
Ruby
81 lines
1.9 KiB
Ruby
# frozen_string_literal: true
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module Gitlab
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module Database
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module LoadBalancing
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# A host that wraps the primary database connection.
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#
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# This class is used to always enable load balancing as if replicas exist,
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# without the need for extra database connections. This ensures that code
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# using the load balancer doesn't have to handle the case where load
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# balancing is enabled, but no replicas have been configured (= the
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# default case).
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class PrimaryHost
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def initialize(load_balancer)
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@load_balancer = load_balancer
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end
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def release_connection
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# no-op as releasing primary connections isn't needed.
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nil
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end
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def enable_query_cache!
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# This could mess up the primary connection, so we make this a no-op
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nil
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end
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def disable_query_cache!
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# This could mess up the primary connection, so we make this a no-op
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nil
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end
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def query_cache_enabled
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@load_balancer.pool.query_cache_enabled
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end
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def connection
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@load_balancer.pool.connection
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end
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def disconnect!(timeout: 120)
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nil
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end
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def offline!
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nil
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end
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def online?
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true
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end
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def primary_write_location
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@load_balancer.primary_write_location
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end
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def database_replica_location
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row = query_and_release(<<-SQL.squish)
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SELECT pg_last_wal_replay_lsn()::text AS location
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SQL
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row['location'] if row.any?
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rescue *Host::CONNECTION_ERRORS
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nil
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end
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def caught_up?(_location)
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true
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end
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def query_and_release(sql)
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connection.select_all(sql).first || {}
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rescue StandardError
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{}
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ensure
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release_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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