method

acquire_connection

v7.1.3.2 - Show latest stable - 0 notes - Class: ActiveRecord::ConnectionAdapters::ConnectionPool

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What's this?

acquire_connection(checkout_timeout) private

Acquire a connection by one of 1) immediately removing one from the queue of available connections, 2) creating a new connection if the pool is not at capacity, 3) waiting on the queue for a connection to become available.

Raises:

ActiveRecord::ConnectionTimeoutError if a connection could not be acquired

Show source

# File activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb, line 647
        def acquire_connection(checkout_timeout)
          # NOTE: we rely on <tt>@available.poll</tt> and +try_to_checkout_new_connection+ to
          # +conn.lease+ the returned connection (and to do this in a +synchronized+
          # section). This is not the cleanest implementation, as ideally we would
          # <tt>synchronize { conn.lease }</tt> in this method, but by leaving it to <tt>@available.poll</tt>
          # and +try_to_checkout_new_connection+ we can piggyback on +synchronize+ sections
          # of the said methods and avoid an additional +synchronize+ overhead.
          if conn = @available.poll || try_to_checkout_new_connection
            conn
          else
            reap
            # Retry after reaping, which may return an available connection,
            # remove an inactive connection, or both
            if conn = @available.poll || try_to_checkout_new_connection
              conn
            else
              @available.poll(checkout_timeout)
            end
          end
        end

acquire_connection

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