sql/pool.lisp

   1 ;;;; -*- Mode: LISP; Syntax: ANSI-Common-Lisp; Base: 10 -*-
   2 ;;;; *************************************************************************
   3 ;;;; FILE IDENTIFICATION
   4 ;;;;
   5 ;;;; Name:          pool.lisp
   6 ;;;; Purpose:       Support function for connection pool
   7 ;;;; Programmers:   Kevin M. Rosenberg, Marc Battyani
   8 ;;;; Date Started:  Apr 2002
   9 ;;;;
  10 ;;;; $Id$
  11 ;;;;
  12 ;;;; This file, part of CLSQL, is Copyright (c) 2002-2003 by Kevin M. Rosenberg
  13 ;;;;
  14 ;;;; CLSQL users are granted the rights to distribute and use this software
  15 ;;;; as governed by the terms of the Lisp Lesser GNU Public License
  16 ;;;; (http://opensource.franz.com/preamble.html), also known as the LLGPL.
  17 ;;;; *************************************************************************
  18
  19 (in-package #:clsql-sys)
  20
  21 (defvar *db-pool* (make-hash-table :test #'equal))
  22 (defvar *db-pool-lock* (make-process-lock "DB Pool lock"))
  23
  24 (defclass conn-pool ()
  25   ((connection-spec :accessor connection-spec :initarg :connection-spec)
  26    (database-type :accessor pool-database-type :initarg :pool-database-type)
  27    (free-connections :accessor free-connections
  28                      :initform (make-array 5 :fill-pointer 0 :adjustable t))
  29    (all-connections :accessor all-connections
  30                     :initform (make-array 5 :fill-pointer 0 :adjustable t))
  31    (lock :accessor conn-pool-lock
  32          :initform (make-process-lock "Connection pool"))))
  33
  34 (defun acquire-from-conn-pool (pool)
  35   (or (with-process-lock ((conn-pool-lock pool) "Acquire from pool")
  36         (and (plusp (length (free-connections pool)))
  37              (vector-pop (free-connections pool))))
  38       (let ((conn (connect (connection-spec pool)
  39                            :database-type (pool-database-type pool)
  40                            :if-exists :new
  41                            :make-default nil)))
  42         (with-process-lock ((conn-pool-lock pool) "Acquire from pool")
  43           (vector-push-extend conn (all-connections pool))
  44           (setf (conn-pool conn) pool))
  45         conn)))
  46
  47 (defun release-to-conn-pool (conn)
  48   (let ((pool (conn-pool conn)))
  49     (with-process-lock ((conn-pool-lock pool) "Release to pool")
  50       (vector-push-extend conn (free-connections pool)))))
  51
  52 (defun clear-conn-pool (pool)
  53   (with-process-lock ((conn-pool-lock pool) "Clear pool")
  54     (loop for conn across (all-connections pool)
  55           do (setf (conn-pool conn) nil)
  56           ;; disconnect may error if remote side closed connection
  57           (ignore-errors (disconnect :database conn)))
  58     (setf (fill-pointer (free-connections pool)) 0)
  59     (setf (fill-pointer (all-connections pool)) 0))
  60   nil)
  61
  62 (defun find-or-create-connection-pool (connection-spec database-type)
  63   "Find connection pool in hash table, creates a new connection pool
  64 if not found"
  65   (with-process-lock (*db-pool-lock* "Find-or-create connection")
  66     (let* ((key (list connection-spec database-type))
  67            (conn-pool (gethash key *db-pool*)))
  68       (unless conn-pool
  69         (setq conn-pool (make-instance 'conn-pool
  70                                        :connection-spec connection-spec
  71                                        :pool-database-type database-type))
  72         (setf (gethash key *db-pool*) conn-pool))
  73       conn-pool)))
  74
  75 (defun acquire-from-pool (connection-spec database-type &optional pool)
  76   (unless (typep pool 'conn-pool)
  77     (setf pool (find-or-create-connection-pool connection-spec database-type)))
  78   (acquire-from-conn-pool pool))
  79
  80 (defun release-to-pool (database)
  81   (release-to-conn-pool database))
  82
  83 (defun disconnect-pooled (&optional clear)
  84   "Disconnects all connections in the pool."
  85   (with-process-lock (*db-pool-lock* "Disconnect pooled")
  86     (maphash
  87      #'(lambda (key conn-pool)
  88          (declare (ignore key))
  89          (clear-conn-pool conn-pool))
  90      *db-pool*)
  91     (when clear (clrhash *db-pool*)))
  92   t)
  93
  94 ;(defun pool-start-sql-recording (pool &key (types :command))
  95 ;  "Start all stream in the pool recording actions of TYPES"
  96 ;  (dolist (con (pool-connections pool))
  97 ;    (start-sql-recording :type types
  98 ;                        :database (connection-database con))))
  99
 100 ;(defun pool-stop-sql-recording (pool &key (types :command))
 101 ;  "Start all stream in the pool recording actions of TYPES"
 102 ;  (dolist (con (pool-connections pool))
 103 ;    (stop-sql-recording :type types
 104 ;                         :database (connection-database con))))
 105
 106 ;(defmacro with-database-connection (pool &body body)
 107 ;  `(let ((connection (obtain-connection ,pool))
 108 ;         (results nil))
 109 ;    (unwind-protect
 110 ;         (with-database ((connection-database connection))
 111 ;           (setq results (multiple-value-list (progn ,@body))))
 112 ;      (release-connection connection))
 113 ;    (values-list results)))