Class: NeverBlock::Pool::FiberedConnectionPool

Inherits:
Object
  • Object
show all
Defined in:
lib/neverblock/io/db/fibered_connection_pool.rb

Overview

This class represents a pool of connections, you hold or release conncetions from the pool hold requests that cannot be fullfiled will be queued the fiber will be paused and resumed later when a connection is avaialble

Large portions of this class were copied and pasted form Sequel’s threaded connection pool

Example:

pool = NeverBlock::Pool::FiberedConnectionPool.new(:size=>16)do # connection creation code goes here end 32.times do Fiber.new do # acquire a connection from the pool pool.hold do |conn| conn.execute(‘something’) # you can use the connection normally now end end.resume end

The pool has support for transactions, just pass true to the pool#hold method and the connection will not be released after the block is finished It is the responsibility of client code to release the connection

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}, &block) ⇒ FiberedConnectionPool

initialize the connection pool using the supplied proc to create the connections You can choose to start them eagerly or lazily (lazy by default) Available options are :size => the maximum number of connections to be created in the pool :eager => (true|false) indicates whether connections should be created initially or when need



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# File 'lib/neverblock/io/db/fibered_connection_pool.rb', line 41

def initialize(options = {}, &block)
  @connections, @busy_connections, @queue = [], {},[]
  @connection_proc = block
  @size = options[:size] || 8
  if options[:eager]
   @size.times do
   @connections << @connection_proc.call
   end
  end
end

Instance Attribute Details

#size ⇒ Object (readonly)

Returns the value of attribute size.



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# File 'lib/neverblock/io/db/fibered_connection_pool.rb', line 32

def size
  @size
end

Instance Method Details

#all_connections ⇒ Object 



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# File 'lib/neverblock/io/db/fibered_connection_pool.rb', line 67

def all_connections
  (@connections + @busy_connections.values).each {|conn| yield(conn)}
end

#hold {|conn| ... } ⇒ Object

If a connection is available, pass it to the block, otherwise pass the fiber to the queue till a connection is available

Yields:

  • (conn) 


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# File 'lib/neverblock/io/db/fibered_connection_pool.rb', line 61

def hold()
 fiber = Fiber.current
  conn = acquire(fiber)
  yield conn
end

#replace_acquired_connection ⇒ Object 



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# File 'lib/neverblock/io/db/fibered_connection_pool.rb', line 52

def replace_acquired_connection
  fiber = Fiber.current
  conn = @connection_proc.call
  @busy_connections[fiber] = conn
  fiber[connection_pool_key] = conn
end