75 lines
2.3 KiB
Ruby
75 lines
2.3 KiB
Ruby
# frozen_string_literal: true
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module Gitlab
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module Database
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class StatActivitySampler
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include ExclusiveLeaseGuard
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# Lookup the pg_stat_get_activity(-1) function instead of pg_stat_activity table.
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# This query returns non-null `query` only for users which the connection is authorised to.
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#
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# application is either sidekiq or puma
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# endpoint refers to a worker class or a route
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# database refers to the configured database field in `config/database.yml`
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#
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# This query omits idle tuples from the pg_stat_activity table as it is only concerned with active or idle in
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# transaction processes.
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PG_STAT_ACTIVITY_SAMPLER_SQL = <<~SQL
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SELECT
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a.matches[1] AS application,
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a.matches[2] AS endpoint,
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a.matches[3] AS database,
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a.state AS state,
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COUNT(*) AS count
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FROM (
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SELECT
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state,
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regexp_matches(query, '^\\s*(?:\\/\\*(?:application:(\\w+),?)?(?:correlation_id:\\w+,?)?(?:jid:\\w+,?)?(?:endpoint_id:([\\w/\\-\\.:\\\#\\s]+),?)?(?:db_config_database:(\\w+),?)?.*?\\*\\/)?\\s*(\\w+)') AS matches
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FROM
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pg_stat_get_activity(-1)
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) a
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GROUP BY application, endpoint, database, state
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SQL
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SAMPLING_INTERVAL = 15
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def self.sample
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Gitlab::Database::LoadBalancing.base_models.each do |bm|
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new(bm.connection).execute
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end
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end
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attr_reader :connection
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def initialize(connection)
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@connection = connection
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@lease_key = "pg_stat_sampler:#{connection.load_balancer.name}:lock"
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end
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def execute
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try_obtain_lease do
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sample = sample_pg_stat_activity
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StatActivity.write(connection.load_balancer.name, sample)
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end
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end
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private
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def lease_timeout
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SAMPLING_INTERVAL
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end
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# Overrides ExclusiveLeaseGuard to not release lease after the sample to ensure we do not oversample
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def lease_release?
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false
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end
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def sample_pg_stat_activity
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Gitlab::Database::LoadBalancing::SessionMap.current(connection.load_balancer).use_primary do
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connection.execute(PG_STAT_ACTIVITY_SAMPLER_SQL).to_a
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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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