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