Class | Sequel::ThreadedConnectionPool |
In: |
lib/sequel/connection_pool/threaded.rb
|
Parent: | Sequel::ConnectionPool |
A connection pool allowing multi-threaded access to a pool of connections. This is the default connection pool used by Sequel.
make_new | -> | default_make_new |
Alias the default make_new method, so subclasses can call it directly. |
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). |
The following additional options are respected:
# File lib/sequel/connection_pool/threaded.rb, line 25 25: def initialize(opts = {}, &block) 26: super 27: @max_size = Integer(opts[:max_connections] || 4) 28: raise(Sequel::Error, ':max_connections must be positive') if @max_size < 1 29: @mutex = Mutex.new 30: @queue = opts[:connection_handling] == :queue 31: @available_connections = [] 32: @allocated = {} 33: @timeout = Integer(opts[:pool_timeout] || 5) 34: @sleep_time = Float(opts[:pool_sleep_time] || 0.001) 35: end
Yield all of the available connections, and the one currently allocated to this thread. This will not yield connections currently allocated to other threads, as it is not safe to operate on them. This holds the mutex while it is yielding all of the available connections, which means that until the method‘s block returns, the pool is locked.
# File lib/sequel/connection_pool/threaded.rb, line 48 48: def all_connections 49: hold do |c| 50: sync do 51: yield c 52: @available_connections.each{|c| yield c} 53: end 54: end 55: end
Removes all connections currently available, 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. If you want to be able to disconnect connections that are currently in use, use the ShardedThreadedConnectionPool, which can do that. This connection pool does not, for performance reasons. To use the sharded pool, pass the :servers=>{} option when connecting to the database.
Once a connection is requested using hold, the connection pool creates new connections to the database.
# File lib/sequel/connection_pool/threaded.rb, line 67 67: def disconnect(opts={}, &block) 68: block ||= @disconnection_proc 69: sync do 70: @available_connections.each{|conn| block.call(conn)} if block 71: @available_connections.clear 72: end 73: end
Chooses the first available connection, 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 89 89: def hold(server=nil) 90: t = Thread.current 91: if conn = owned_connection(t) 92: return yield(conn) 93: end 94: begin 95: unless conn = acquire(t) 96: time = Time.now 97: timeout = time + @timeout 98: sleep_time = @sleep_time 99: sleep sleep_time 100: until conn = acquire(t) 101: raise(::Sequel::PoolTimeout) if Time.now > timeout 102: sleep sleep_time 103: end 104: end 105: yield conn 106: rescue Sequel::DatabaseDisconnectError 107: oconn = conn 108: conn = nil 109: @disconnection_proc.call(oconn) if @disconnection_proc && oconn 110: @allocated.delete(t) 111: raise 112: ensure 113: sync{release(t)} if conn 114: end 115: end