Class: Gitlab::Database::Transaction::Observer

Inherits:
Object
  • Object
show all
Defined in:
lib/gitlab/database/transaction/observer.rb

Constant Summary collapse

INSTRUMENTED_STATEMENTS = 
%w[BEGIN SAVEPOINT ROLLBACK RELEASE].freeze
LONGEST_COMMAND_LENGTH = 
'ROLLBACK TO SAVEPOINT'.length
START_COMMENT = 
'/*'
END_COMMENT = 
'*/'

Class Method Summary collapse

Class Method Details

.extract_sql_command(sql) ⇒ Object 



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# File 'lib/gitlab/database/transaction/observer.rb', line 47

def self.extract_sql_command(sql)
  return sql unless sql.start_with?(START_COMMENT)

  index = sql.index(END_COMMENT)

  return sql unless index

  # /* comment */ SELECT
  #
  # We offset using a position of the end comment + 1 character to
  # accomodate a space between Marginalia comment and a SQL statement.
  offset = index + END_COMMENT.length + 1

  # Avoid duplicating the entire string. This isn't optimized to
  # strip extra spaces, but we assume that this doesn't happen
  # for performance reasons.
  sql[offset..offset + LONGEST_COMMAND_LENGTH]
end

.instrument_transactions(cmd, event) ⇒ Object 



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# File 'lib/gitlab/database/transaction/observer.rb', line 12

def self.instrument_transactions(cmd, event)
  connection = event.payload[:connection]
  manager = connection&.transaction_manager
  return unless manager.respond_to?(:transaction_context)

  context = manager.transaction_context
  return if context.nil?

  if cmd.start_with?('BEGIN')
    context.set_start_time
    context.set_depth(0)
    context.track_sql(event.payload[:sql])
    context.initialize_external_http_tracking
  elsif cmd.start_with?('SAVEPOINT', 'EXCEPTION')
    context.set_depth(manager.open_transactions)
    context.increment_savepoints
    context.track_backtrace(caller)
  elsif cmd.start_with?('ROLLBACK TO SAVEPOINT')
    context.increment_rollbacks
  elsif cmd.start_with?('RELEASE SAVEPOINT ')
    context.increment_releases
  end
end

.register! ⇒ Object 



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# File 'lib/gitlab/database/transaction/observer.rb', line 36

def self.register!
  ActiveSupport::Notifications.subscribe('sql.active_record') do |event|
    sql = event.payload.dig(:sql).to_s
    cmd = extract_sql_command(sql)

    if cmd.start_with?(*INSTRUMENTED_STATEMENTS)
      self.instrument_transactions(cmd, event)
    end
  end
end