Module: SafePgMigrations::Helpers::BlockingActivitySelector

Included in:
BlockingActivityLogger
Defined in:
lib/safe-pg-migrations/helpers/blocking_activity_selector.rb

Constant Summary collapse

FILTERED_COLUMNS = 
%w[
  blocked_activity.xact_start
  blocked_locks.locktype
  blocked_locks.mode
  blocking_activity.pid
  blocked_locks.transactionid
].freeze
VERBOSE_COLUMNS = 
%w[
  blocking_activity.pid
  blocking_activity.query
  blocked_activity.xact_start
].freeze

Instance Method Summary collapse

Instance Method Details

#select_blocking_queries_sql ⇒ Object 



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# File 'lib/safe-pg-migrations/helpers/blocking_activity_selector.rb', line 20

def select_blocking_queries_sql
  columns =
    (
      if SafePgMigrations.config.blocking_activity_logger_verbose
        VERBOSE_COLUMNS
      else
        FILTERED_COLUMNS
      end
    )

  <<~SQL.squish
    SELECT #{columns.join(', ')}
    FROM pg_catalog.pg_locks           blocked_locks
    JOIN pg_catalog.pg_stat_activity   blocked_activity
      ON blocked_activity.pid = blocked_locks.pid
    JOIN pg_catalog.pg_locks           blocking_locks
      ON blocking_locks.locktype = blocked_locks.locktype
      AND blocking_locks.DATABASE      IS NOT DISTINCT FROM blocked_locks.DATABASE
      AND blocking_locks.relation      IS NOT DISTINCT FROM blocked_locks.relation
      AND blocking_locks.page          IS NOT DISTINCT FROM blocked_locks.page
      AND blocking_locks.tuple         IS NOT DISTINCT FROM blocked_locks.tuple
      AND blocking_locks.virtualxid    IS NOT DISTINCT FROM blocked_locks.virtualxid
      AND blocking_locks.transactionid IS NOT DISTINCT FROM blocked_locks.transactionid
      AND blocking_locks.classid       IS NOT DISTINCT FROM blocked_locks.classid
      AND blocking_locks.objid         IS NOT DISTINCT FROM blocked_locks.objid
      AND blocking_locks.objsubid      IS NOT DISTINCT FROM blocked_locks.objsubid
      AND blocking_locks.pid != blocked_locks.pid
    JOIN pg_catalog.pg_stat_activity   blocking_activity
      ON blocking_activity.pid = blocking_locks.pid
    WHERE blocked_locks.pid = %d
  SQL
end