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.
USE_WAITER | = | RUBY_VERSION >= '1.9' |
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 34 34: def initialize(db, opts = OPTS) 35: super 36: @max_size = Integer(opts[:max_connections] || 4) 37: raise(Sequel::Error, ':max_connections must be positive') if @max_size < 1 38: @mutex = Mutex.new 39: @connection_handling = opts[:connection_handling] 40: @available_connections = [] 41: @allocated = {} 42: @timeout = Float(opts[:pool_timeout] || 5) 43: 44: if USE_WAITER 45: @waiter = ConditionVariable.new 46: else 47: # :nocov: 48: @sleep_time = Float(opts[:pool_sleep_time] || 0.001) 49: # :nocov: 50: end 51: 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 58 58: def all_connections 59: hold do |c| 60: sync do 61: yield c 62: @available_connections.each{|conn| yield conn} 63: end 64: end 65: 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 77 77: def disconnect(opts=OPTS) 78: conns = nil 79: sync do 80: conns = @available_connections.dup 81: @available_connections.clear 82: end 83: conns.each{|conn| disconnect_connection(conn)} 84: 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 100 100: def hold(server=nil) 101: t = Thread.current 102: if conn = owned_connection(t) 103: return yield(conn) 104: end 105: begin 106: conn = acquire(t) 107: yield conn 108: rescue Sequel::DatabaseDisconnectError, *@error_classes => e 109: if disconnect_error?(e) 110: oconn = conn 111: conn = nil 112: disconnect_connection(oconn) if oconn 113: @allocated.delete(t) 114: end 115: raise 116: ensure 117: sync{release(t)} if conn 118: end 119: end