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(db, opts = OPTS) 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: @connection_handling = opts[:connection_handling] 31: @available_connections = [] 32: @allocated = {} 33: @timeout = Float(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 42 42: def all_connections 43: hold do |c| 44: sync do 45: yield c 46: @available_connections.each{|conn| yield conn} 47: end 48: end 49: 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 61 61: def disconnect(opts=OPTS) 62: sync do 63: @available_connections.each{|conn| db.disconnect_connection(conn)} 64: @available_connections.clear 65: end 66: 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 82 82: def hold(server=nil) 83: t = Thread.current 84: if conn = owned_connection(t) 85: return yield(conn) 86: end 87: begin 88: unless conn = acquire(t) 89: time = Time.now 90: timeout = time + @timeout 91: sleep_time = @sleep_time 92: sleep sleep_time 93: until conn = acquire(t) 94: raise(::Sequel::PoolTimeout) if Time.now > timeout 95: sleep sleep_time 96: end 97: end 98: yield conn 99: rescue Sequel::DatabaseDisconnectError 100: oconn = conn 101: conn = nil 102: db.disconnect_connection(oconn) if oconn 103: @allocated.delete(t) 104: raise 105: ensure 106: sync{release(t)} if conn 107: end 108: end