1 ;;;; -*- Mode: LISP; Syntax: ANSI-Common-Lisp; Base: 10 -*-
2 ;;;; *************************************************************************
3 ;;;; FILE IDENTIFICATION
6 ;;;; Purpose: Support function for connection pool
7 ;;;; Programmers: Kevin M. Rosenberg, Marc Battyani
8 ;;;; Date Started: Apr 2002
10 ;;;; This file, part of CLSQL, is Copyright (c) 2002-2010 by Kevin M. Rosenberg
12 ;;;; CLSQL users are granted the rights to distribute and use this software
13 ;;;; as governed by the terms of the Lisp Lesser GNU Public License
14 ;;;; (http://opensource.franz.com/preamble.html), also known as the LLGPL.
15 ;;;; *************************************************************************
17 (in-package #:clsql-sys)
19 (defvar *db-pool* (make-hash-table :test #'equal))
20 (defvar *db-pool-lock* (make-process-lock "DB Pool lock"))
22 (defclass conn-pool ()
23 ((connection-spec :accessor connection-spec :initarg :connection-spec)
24 (database-type :accessor pool-database-type :initarg :pool-database-type)
25 (free-connections :accessor free-connections
26 :initform (make-array 5 :fill-pointer 0 :adjustable t))
27 (all-connections :accessor all-connections
28 :initform (make-array 5 :fill-pointer 0 :adjustable t))
29 (lock :accessor conn-pool-lock
30 :initform (make-process-lock "Connection pool"))))
32 (defun acquire-from-conn-pool (pool)
33 (or (with-process-lock ((conn-pool-lock pool) "Acquire from pool")
34 (when (plusp (length (free-connections pool)))
35 (let ((pconn (vector-pop (free-connections pool))))
36 ;; test if connection still valid.
37 ;; Currently, on supported on MySQL
39 ((eq :mysql (database-type pconn))
41 (database-query "SHOW ERRORS LIMIT 1" pconn nil nil)
43 ;; we could check for error type 2006 for "SERVER GONE AWAY",
44 ;; but, it's safer just to disconnect the pooled conn for any error
45 (warn "Database connection ~S had an error when attempted to be acquired from the pool:
49 (ignore-errors (database-disconnect pconn))
51 (:no-error (res fields)
52 (declare (ignore res fields))
56 (let ((conn (connect (connection-spec pool)
57 :database-type (pool-database-type pool)
60 (with-process-lock ((conn-pool-lock pool) "Acquire from pool")
61 (vector-push-extend conn (all-connections pool))
62 (setf (conn-pool conn) pool))
65 (defun release-to-conn-pool (conn)
66 (let ((pool (conn-pool conn)))
67 (with-process-lock ((conn-pool-lock pool) "Release to pool")
68 (vector-push-extend conn (free-connections pool)))))
70 (defun clear-conn-pool (pool)
71 (with-process-lock ((conn-pool-lock pool) "Clear pool")
72 (loop for conn across (all-connections pool)
73 do (setf (conn-pool conn) nil)
74 ;; disconnect may error if remote side closed connection
75 (ignore-errors (disconnect :database conn)))
76 (setf (fill-pointer (free-connections pool)) 0)
77 (setf (fill-pointer (all-connections pool)) 0))
80 (defun find-or-create-connection-pool (connection-spec database-type)
81 "Find connection pool in hash table, creates a new connection pool
83 (with-process-lock (*db-pool-lock* "Find-or-create connection")
84 (let* ((key (list connection-spec database-type))
85 (conn-pool (gethash key *db-pool*)))
87 (setq conn-pool (make-instance 'conn-pool
88 :connection-spec connection-spec
89 :pool-database-type database-type))
90 (setf (gethash key *db-pool*) conn-pool))
93 (defun acquire-from-pool (connection-spec database-type &optional pool)
94 (unless (typep pool 'conn-pool)
95 (setf pool (find-or-create-connection-pool connection-spec database-type)))
96 (acquire-from-conn-pool pool))
98 (defun release-to-pool (database)
99 (release-to-conn-pool database))
101 (defun disconnect-pooled (&optional clear)
102 "Disconnects all connections in the pool."
103 (with-process-lock (*db-pool-lock* "Disconnect pooled")
105 #'(lambda (key conn-pool)
106 (declare (ignore key))
107 (clear-conn-pool conn-pool))
109 (when clear (clrhash *db-pool*)))
112 ;(defun pool-start-sql-recording (pool &key (types :command))
113 ; "Start all stream in the pool recording actions of TYPES"
114 ; (dolist (con (pool-connections pool))
115 ; (start-sql-recording :type types
116 ; :database (connection-database con))))
118 ;(defun pool-stop-sql-recording (pool &key (types :command))
119 ; "Start all stream in the pool recording actions of TYPES"
120 ; (dolist (con (pool-connections pool))
121 ; (stop-sql-recording :type types
122 ; :database (connection-database con))))
124 ;(defmacro with-database-connection (pool &body body)
125 ; `(let ((connection (obtain-connection ,pool))
128 ; (with-database ((connection-database connection))
129 ; (setq results (multiple-value-list (progn ,@body))))
130 ; (release-connection connection))
131 ; (values-list results)))