Class/Module Index [+]

Quicksearch

Sequel::ThreadedConnectionPool

A connection pool allowing multi-threaded access to a pool of connections. This is the default connection pool used by Sequel.

Attributes

allocated[R]

A hash with thread keys and connection values for currently allocated connections.

available_connections[R]

An array of connections that are available for use by the pool.

max_size[R]

The maximum number of connections this pool will create (per shard/server if sharding).

Public Class Methods

new(opts = {}, &block) click to toggle source

The following additional options are respected:

  • :max_connections - The maximum number of connections the connection pool will open (default 4)

  • :pool_sleep_time - The amount of time to sleep before attempting to acquire a connection again (default 0.001)

  • :pool_timeout - The amount of seconds to wait to acquire a connection before raising a PoolTimeoutError (default 5)

# File lib/sequel/connection_pool/threaded.rb, line 22
def initialize(opts = {}, &block)
  super
  @max_size = Integer(opts[:max_connections] || 4)
  raise(Sequel::Error, ':max_connections must be positive') if @max_size < 1
  @mutex = Mutex.new  
  @available_connections = []
  @allocated = {}
  @timeout = Integer(opts[:pool_timeout] || 5)
  @sleep_time = Float(opts[:pool_sleep_time] || 0.001)
end

Public Instance Methods

disconnect(opts={}, &block) click to toggle source

Removes all connections currently available on all servers, optionally yielding each connection to the given block. This method has the effect of disconnecting from the database, assuming that no connections are currently being used.

Once a connection is requested using hold, the connection pool creates new connections to the database.

# File lib/sequel/connection_pool/threaded.rb, line 46
def disconnect(opts={}, &block)
  block ||= @disconnection_proc
  sync do
    @available_connections.each{|conn| block.call(conn)} if block
    @available_connections.clear
  end
end
hold(server=nil) click to toggle source

Chooses the first available connection to the given server, or if none are available, creates a new connection. Passes the connection to the supplied block:

pool.hold {|conn| conn.execute('DROP TABLE posts')}

Pool#hold is re-entrant, meaning it can be called recursively in the same thread without blocking.

If no connection is immediately available and the pool is already using the maximum number of connections, Pool#hold will block until a connection is available or the timeout expires. If the timeout expires before a connection can be acquired, a Sequel::PoolTimeout is raised.

# File lib/sequel/connection_pool/threaded.rb, line 68
def hold(server=nil)
  t = Thread.current
  if conn = owned_connection(t)
    return yield(conn)
  end
  begin
    unless conn = acquire(t)
      time = Time.now
      timeout = time + @timeout
      sleep_time = @sleep_time
      sleep sleep_time
      until conn = acquire(t)
        raise(::Sequel::PoolTimeout) if Time.now > timeout
        sleep sleep_time
      end
    end
    yield conn
  rescue Sequel::DatabaseDisconnectError
    oconn = conn
    conn = nil
    @disconnection_proc.call(oconn) if @disconnection_proc && oconn
    @allocated.delete(t)
    raise
  ensure
    sync{release(t)} if conn
  end
end
size() click to toggle source

The total number of connections opened for the given server, should be equal to available_connections.length + allocated.length.

# File lib/sequel/connection_pool/threaded.rb, line 35
def size
  @allocated.length + @available_connections.length
end

[Validate]

Generated with the Darkfish Rdoc Generator 2.